id
stringlengths 24
24
| doi
stringlengths 28
32
| title
stringlengths 8
495
| abstract
stringlengths 17
5.7k
| authors
stringlengths 5
2.65k
| categories
stringlengths 4
700
| license
stringclasses 3
values | origin
stringclasses 1
value | date
stringdate 1970-01-01 00:00:00
2025-03-24 00:00:00
| url
stringlengths 119
367
⌀ |
|---|---|---|---|---|---|---|---|---|---|
621a3f7e97f210479ff57b6c | 10.26434/chemrxiv-2022-vnh52 | Regioselective Fluoroalkylphosphorylation of Unactivated Alkenes via Radical–Mediated Alkoxylphosphane Rearrangement | A regioselective radical fluoroalkylphosphorylation of unactivated alkenes has been developed by a one-pot twosteps reaction of (bis)homoallylic alcohols, organophosphine chlorides (R2PCl), and fluoroalkyl iodides (RFI) under visible light irradiation. This protocol employs the radical rearrangement of the in situ formed alkoxyphosphane for the first time to regiospecific installing a phosphonyl group onto the inner carbon of terminal olefins in alkene difunctionalization via C-P bond formation and C-O bond homolytic cleavage. Consequently, a series of high value-added fluoroalkylphosphorylated alkyl iodides and alcohols are easily and efficiently synthesized by subsequent iodination and hydroxylation of the generated carbon-centered radicals. | Dong-Tai Xie; Hong-Lei Chen; Dian Wei; Bang-Yi Wei; Zheng-Hu Li ; Jian-Wu Zhang; Wei Yu; Bing Han | Organic Chemistry; Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2022-03-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/621a3f7e97f210479ff57b6c/original/regioselective-fluoroalkylphosphorylation-of-unactivated-alkenes-via-radical-mediated-alkoxylphosphane-rearrangement.pdf |
66bcbdc3f3f4b05290dcf8bc | 10.26434/chemrxiv-2024-f6qmr | Evaluation of TOCSY mixing for sensitivity-enhancement in solid-state NMR and application of 4D experiments for side-chain assignments of the full-length 30 kDa membrane protein GlpG | Chemical shift assignments of large membrane proteins by solid-state NMR experiments are challenging. Recent advancements in sensitivity-enhanced pulse sequences, have made it feasible to acquire 1H-detected 4D spectra of these challenging protein samples within reasonable timeframes. However, obtaining unambiguous assignments remains difficult without access to side-chain chemical shifts. Drawing inspiration from sensitivity-enhanced TOCSY experiments in solution NMR, we have explored the potential of 13C-13C TOCSY mixing as a viable option for triple sensitivity-enhanced 4D experiments aimed at side-chain assignments in solid-state NMR. Through simulations and experimental trials, we have identified optimal conditions to achieve uniform transfer efficiency for both transverse components and to minimize undesired cross-transfers. Our experiments, conducted on the 30 kDa membrane protein GlpG embedded in E. coli liposomes, have demonstrated enhanced sensitivity compared to the most effective dipolar and J-coupling-based 13C-13C mixing sequences. Notably, a non-uniformly sampled 4D hCXCANH spectrum with exceptionally high sensitivity was obtained in just a few days using a 600 MHz spectrometer equipped with a 1.3 mm probe operating at a magic angle spinning rate of 55 kHz. | Carl Öster; Veniamin Chevelkov; Adam Lange | Physical Chemistry; Biological and Medicinal Chemistry; Analytical Chemistry; Biophysics; Biophysical Chemistry; Spectroscopy (Physical Chem.) | CC BY 4.0 | CHEMRXIV | 2024-08-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66bcbdc3f3f4b05290dcf8bc/original/evaluation-of-tocsy-mixing-for-sensitivity-enhancement-in-solid-state-nmr-and-application-of-4d-experiments-for-side-chain-assignments-of-the-full-length-30-k-da-membrane-protein-glp-g.pdf |
650f737d60c37f4f7653afa4 | 10.26434/chemrxiv-2023-bt10w | Fabrication of Large Area Metal-on-Carbon Catalytic Condensers for Programmable Catalysis | Catalytic condensers stabilize charge on either side of a high-k dielectric film to modulate the electronic states of a catalytic layer for electronic control of surface reactions. Here, carbon sputtering provided for fast, large-scale fabrication of metal-carbon catalytic condensers required for industrial application. Carbon films were sputtered on HfO2 dielectric/p-type Si with different thickness (1, 3, 6, 10 nm), and the enhancement of conductance and capacitance of carbon films was observed upon increasing carbon thickness following thermal treatment at 400 °C. After Pt deposition on the carbon films, the Pt catalytic condenser exhibited high capacitance of ~210 nF/cm^2 that was maintained at a frequency ~1,000 Hz, satisfying the requirement for a dynamic catalyst to implement catalytic resonance. Temperature programmed desorption of carbon monoxide yielded CO desorption peaks which shifted in temperature with varying potential applied to the condenser (−6 V or 6 +V) indicating a shift in the binding energy of carbon monoxide on the Pt condenser surface. A substantial increase of capacitance (~2,000 nF/cm^2) of the Pt-on-carbon devices was observed at elevated temperatures of 400 °C that can modulate ~10% of charge per metal atom when 10 V potential was applied. A large catalytic condenser of 42 cm^2 area Pt/C/HfO2/Si exhibited high capacitance of 9,393 nF with low leakage current/capacitive current ratio (<0.1), demonstrating the practicality and versatility of the facile, large-scale fabrication method for metal-carbon catalytic condensers. | Kyung-Ryul Oh; Tzia Ming Onn; Amber Walton; Michael L. Odlyzko; C. Daniel Frisbie; Paul Dauenhauer | Catalysis; Electrocatalysis; Heterogeneous Catalysis; Nanocatalysis - Reactions & Mechanisms | CC BY NC ND 4.0 | CHEMRXIV | 2023-09-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/650f737d60c37f4f7653afa4/original/fabrication-of-large-area-metal-on-carbon-catalytic-condensers-for-programmable-catalysis.pdf |
60c7449b842e656db3db24b7 | 10.26434/chemrxiv.8014715.v2 | Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes | <p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p> | Georg Dewald; Saneyuki Ohno; Marvin Kraft; Raimund Koerver; Paul Till; Nella Vargas; Juergen Janek; Wolfgang Zeier | Polyelectrolytes - Materials; Solid State Chemistry; Energy Storage; Electrochemistry - Mechanisms, Theory & Study; Interfaces | CC BY NC ND 4.0 | CHEMRXIV | 2019-09-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7449b842e656db3db24b7/original/experimental-assessment-of-the-practical-oxidative-stability-of-lithium-thiophosphate-solid-electrolytes.pdf |
6310868bf07ee126dcf9ba79 | 10.26434/chemrxiv-2022-6g260 | Towards Complementary Characterization of the Chemical Bond | A precise discussion of a single bond requires consideration of two-particle wave function for the particles involved. Here we define and determine rigorously the intrinsic covalency and connected characteristics on the canonical example of H2 molecule. This is achieved by starting from analytic form for the two-particle wave function for electrons forming the bond, in which we single out the atomic contribution (\textit{atomicity}) in an unequivocal manner. The presence the of atomicity and ionicity factors complements the existing attributes of the bond. In this way, a gradual evolution of the molecular state to its two-atomic correspondant is traced systematically with increasing interatomic distance. In effect, a direct relation to the onset of incipient
Mott-Hubbard atomicity (Mottness) to the intrinsic covalency and ionicity is established. This goal is achieved by combining the single--particle wave function readjustment with a simultaneous determination of two-particle states in the particle (second--quantization) representation | Maciej Hendzel; Maciej Fidrysiak; Józef Spałek | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Theory - Computational; Physical and Chemical Properties | CC BY 4.0 | CHEMRXIV | 2022-09-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6310868bf07ee126dcf9ba79/original/towards-complementary-characterization-of-the-chemical-bond.pdf |
678baed0fa469535b984f021 | 10.26434/chemrxiv-2025-1rklr | Difluoroenol Phosphinates as Versatile Difluoroenolate Surrogates: Synthesis and Applications in Defluorination and Deoxygenative Coupling | We report defluorinative and deoxygenative functionalization reactions of trifluoromethyl ketones mediated by the phospha-Brook rearrangement, offering a streamlined approach to selectively modifying fluorinated compounds. Trifluoromethyl ke-tones react with phosphine oxides to undergo a phospha-Brook rearrangement followed by β-fluoride elimination, providing difluoromethyl ketones in good yields. By tuning the reaction conditions, we achieved the selective one-pot synthesis of monofluoromethyl ketones and methyl ketones, demonstrating the method’s versatility across a range of fluorine-containing derivatives. Furthermore, we successfully demonstrated a range of deoxygenative transformations of key intermediates, such as difluoroenol phosphinates, showcasing their potential as versatile building blocks for diverse functionalizations. These findings not only expand the synthetic toolbox for fluorine-containing molecules but also highlight the utility of phospho-nate intermediates in developing novel reaction pathways. | Miki B. Kurosawa; Shuhei Shimoyama; Hiroki Tanaka; Kenta Kato; Junichiro Yamaguchi | Organic Chemistry; Organic Synthesis and Reactions | CC BY NC 4.0 | CHEMRXIV | 2025-01-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/678baed0fa469535b984f021/original/difluoroenol-phosphinates-as-versatile-difluoroenolate-surrogates-synthesis-and-applications-in-defluorination-and-deoxygenative-coupling.pdf |
6169c06f2aca537fab64e509 | 10.26434/chemrxiv-2021-gw0h4 | Thermal aging of heteroatom substituted Keggin type aluminum oxo polycation solutions: Aggregation behavior and impacts on dissolved organic carbon and turbidity removal | Coagulation processes within water treatment plays an important role in contaminant removal and aluminum-oxo Keggin polycations are proved to be an effective coagulating agents. Previous work demonstrated that heteroatom substitution within the Keggin-type polycation ε-Al13 to form ε-GaAl12 and ε-GeAl12 can enhance removal of bacteria, DOC, and turbidity from wastewater. Additional hydrolysis of the ε-Al13 species to form larger Al30 species has also been shown to improve coagulation, but this aspect has not been evaluated for the ε-GaAl12 and ε-GeAl12 systems. In the current study, hydrolysis of ε-Al13, ε-GaAl12 and ε-GeAl12 was promoted through hydrothermal aging to evaluate the overall solution stability/behavior and water treatment efficiency. Turbidity measurement of aged solution indicated that Ga substituted aluminum-oxo Keggin polycations remain stable in solution and DLS studies demonstrated greater diversity in particle sizes within the system. Additional thermogravimetric analyses of metal hydroxide precipitates formed from the aging studies indicate that the GaAl12 system behaves more like an amorphous Al(OH)3 phase, which has higher solubility than other aluminum hydroxide phases. Hydrothermal aging did not significantly change %DOC removal as all solution showed high efficiency for removal across a range of pH values. GaAl12 solutions demonstrated good turbidity removal efficiency in all pH range, with enhanced performance at pH 5. The study suggests that larger, relatively stable oligomers do exist within the aged GaAl12 solutions that may contribute to enhanced contaminant removal in a similar manner to what is observed within the PACl-Al30 coagulant. | Mohammad Shohel; Jack A. Smith; Margaret A. Carolan; Tori Z. Forbes | Chemical Engineering and Industrial Chemistry; Water Purification | CC BY NC ND 4.0 | CHEMRXIV | 2021-10-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6169c06f2aca537fab64e509/original/thermal-aging-of-heteroatom-substituted-keggin-type-aluminum-oxo-polycation-solutions-aggregation-behavior-and-impacts-on-dissolved-organic-carbon-and-turbidity-removal.pdf |
611abebd18911ded48e1ec50 | 10.26434/chemrxiv-2021-5j78t | Molecular docking and ADMET based study to identify potential phytochemical inhibitors for papain-like protease of SARS-CoV-2 | The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative pathogen for the novel COVID-19 disease. SARS-CoV-2 papain-like protease (PLpro) is responsible for viral replication and host innate immunity suppression. Thus, this study aimed to explore potential phytochemical inhibitors against this dual therapeutic target using virtual screening methods. Thirty-one phytochemicals with reported anti-SARS-CoV-1 PLpro activity were used to construct the phytochemical library along with two positive controls. Molecular docking using AutoDock 4.2 was employed to calculate binding affinity and inhibition constant of each compound within the S3/S4 binding pocket of SARS-CoV-2 PLpro. Based on the docking results, twelve compounds were subjected to non-covalent interaction analysis utilizing the Discovery Studio Visualizer software. Further, their physicochemical, pharmacokinetics and toxicity descriptors were evaluated using molinspiration and pkCSM web servers, respectively. Hirsutenone from Alnus japonica and broussoflavan A from Broussonetia papyrifera, displayed the strongest binding affinity (-8.23 kcal/mol and -8.13 kcal/mol), lowest inhibition constant (920.39 nM and 1.1 μM) and highest ligand efficiency (0.34 and 0.26) among all phytochemicals towards the binding pocket of SARS-CoV-2 PLpro, demonstrating superiority to PLpro inhibitors, 3k and GRL0617 which were used as positive controls. Additionally, hirsutenone, broussoflavan A and broussochalcone A (from Broussonetia papyrifera) possessed favorable physicochemical properties for oral drug development, satisfying Lipinski’s and Veber’s rules. Furthermore, in silico pharmacokinetics and toxicity predictions revealed that the three aforementioned phytochemicals are water soluble, non-mutagenic, non-hepatotoxic and biologically safe. Hence these lead compounds might be exploited to accelerate the drug discovery process against the ongoing COVID-19 infection. | Padmika Wadanambi; Uthpali Mannapperuma; Nimanthi Jayathilaka | Theoretical and Computational Chemistry; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2021-08-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/611abebd18911ded48e1ec50/original/molecular-docking-and-admet-based-study-to-identify-potential-phytochemical-inhibitors-for-papain-like-protease-of-sars-co-v-2.pdf |
6273cd02809e3265ed84013e | 10.26434/chemrxiv-2022-js6j0 | Cyclooctatetraenide-Based Single-Ion Magnets
Featuring Bulky Cyclopentadienyl Ligand | We report a family of organometallic rare-earth complexes with the general formula (COT)M(Cpttt) (where (COT)2– = cyclooctatetraenide, (Cpttt)– = 1,2,4-tri(tert-butyl)cyclopentadienide, M = Y(III), Nd(III), Dy(III) and Er(III)). Similarly to the prototypical Er(III) analog featuring pentamethylcyclopentadienyl ligand (Cp*)–, (COT)Er(Cpttt) behaves as a single-ion magnet. However, the introduction of the sterically demanding (Cpttt)– imposes geometric constraints that lead to a streamlined magnetic relaxation behavior compared to the (Cp*)– containing complexes. Consequently, (COT)Er(Cpttt) can be viewed as a model representative of this organometallic single-ion magnet architecture. In addition, we demonstrate that the increased steric profile associated with the (Cpttt)– ligand permits preparation, structural characterization and interrogation of magnetic properties of the early-lanthanide complex, (COT)Nd(Cpttt). Such a mononuclear derivative could not be obtained when a (Cp*)– ligand was employed, a testament to larger ionic radius of this early lanthanide ion. | Maciej Damian Korzyński; Moritz Bernhardt; Vladyslav Romankov; Jan Dreiser; Guy Matmon; Fabrice Pointillart; Boris Le Guennic; Olivier Cador; Christophe Copéret | Inorganic Chemistry; Organometallic Chemistry; Lanthanides and Actinides; Magnetism; Organometallic Compounds | CC BY NC ND 4.0 | CHEMRXIV | 2022-05-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6273cd02809e3265ed84013e/original/cyclooctatetraenide-based-single-ion-magnets-featuring-bulky-cyclopentadienyl-ligand.pdf |
60c74171337d6c4f84e268e2 | 10.26434/chemrxiv.8055728.v1 | Like Dissolves Like? A Comprehensive Evaluation of Partial Solubility Parameters to Predict Polymer-Drug Compatibility in Ultra-High Drug Loaded Polymer Micelles | <p></p><p>Despite decades of research, our
understanding of the molecular interactions between drugs and polymers in drug
loaded polymer micelles does not extend much beyond concepts such as
“like-dissolves-like“ or hydrophilic/hydrophobic. However, polymer-drug
compatibility strongly affects formulation properties and therefore the
translation of a formulation into the clinics. Specific interactions such as
hydrogen-bonding, π-π stacking or coordination interactions can be utilized to
increase drug-loading. This is commonly based on trial-and-error and eventually
leads to an optimized drug carrier. Unfortunately, due to the unique
characteristics of each drug, the deduction of advanced general concepts
remains challenging. Furthermore, the introduction of complex moieties or
specifically modified polymers hampers systematic investigations regarding
polymer drug-compatibility as well as clinical translation. In this study, we
reduced the complexity in order to isolate crucial factors determining
drug-loading. Therefore, the compatibility of 18 different amphiphilic polymers
for 5 different hydrophobic drugs was determined empirically. Subsequently, the
obtained specificities were compared to theoretical compatibilities derived
from either the Flory-Huggins interaction parameter or Hansen solubility
parameters. In general, Flory-Huggins interaction parameters were less suited
to correctly estimate the experimental drug solubilization compared to the
Hansen solubility parameters. The latter were able to correctly predict some
trend regarding good and poor solubilizers, yet the overall predicitive
strength of Hansen Solubility parameters is clearly unsatisfactory.</p><br /><p></p> | Michael M Lübtow; Malik Salman Haider; Marius Kirsch; Stefanie Klisch; Robert Luxenhofer | Drug delivery systems; Polymerization (Polymers) | CC BY NC ND 4.0 | CHEMRXIV | 2019-04-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74171337d6c4f84e268e2/original/like-dissolves-like-a-comprehensive-evaluation-of-partial-solubility-parameters-to-predict-polymer-drug-compatibility-in-ultra-high-drug-loaded-polymer-micelles.pdf |
65d31d419138d23161712db5 | 10.26434/chemrxiv-2024-f9dlj | Speciation of the proton in water-in-salt electrolytes | Water-in-salt (WiS) electrolytes are promising systems for a variety of energy storage devices. Indeed, they represent a great alternative to conventional organic electrolytes thanks to their environmental friendliness, non-flammability, and good electrochemical stability. Understanding the behaviour of such systems and their local organisation is a key direction for their rational design and successful implementation at the industrial scale. In the present paper, we focus our investigation on the 21 m bis(trifluoromethanesulfonyl)imide (LiTFSI) WiS electrolyte, recently reported to have acidic pH values. We explore the speciation of an excess proton in this system and its dependence on the initial local environment using ab initio molecular dynamics simulations. In particular, we observe the formation of HTFSI acid in WiS system, known to act as a superacid in water. This acid is stabilised in the WiS solution for several picoseconds thanks to the formation of a complex with water molecules and a neighboring TFSI– anion. We further investigate how the excess proton affects the microstructure of WiS, in particular, the oligomerisation of lithium cations, and report possible notable perturbations of lithium nanochain organisation in some cases. These two phenomena are particularly important when considering WiS as electrolytes in batteries and supercapacitors, and our results contribute to the comprehension of these systems on the molecular level. | Kateryna Goloviznina; Alessandra Serva; Mathieu Salanne | Theoretical and Computational Chemistry; Physical Chemistry; Energy; Computational Chemistry and Modeling; Physical and Chemical Properties; Structure | CC BY NC ND 4.0 | CHEMRXIV | 2024-02-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65d31d419138d23161712db5/original/speciation-of-the-proton-in-water-in-salt-electrolytes.pdf |
66fbbbb5cec5d6c142c540d2 | 10.26434/chemrxiv-2024-sqf2v | Accelerating Molecular Dynamics Simulations Using Socket-Based Inter-Process Communication | Molecular Dynamics (MD) simulations are essential for studying the time evolution of molecular systems. Still, their efficiency is often bottlenecked by file-based Inter-Process Communication (IPC) between MD and Electronic Structure (ES) programs. We present a socket-based IPC implementation that dramatically accelerates MD simulations, reducing computational time by over tenfold compared to traditional file-based methods. Our approach, applied to nonadiabatic molecular dynamics with the Newton-X program, eliminates disk read/write overhead, allowing for faster simulations over longer timescales. This method opens the door to more efficient high-throughput simulations, providing new opportunities for exploring complex molecular processes in real-time. | Matheus O. Bispo; Mario Barbatti | Theoretical and Computational Chemistry | CC BY 4.0 | CHEMRXIV | 2024-10-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66fbbbb5cec5d6c142c540d2/original/accelerating-molecular-dynamics-simulations-using-socket-based-inter-process-communication.pdf |
657cbbea66c138172946233f | 10.26434/chemrxiv-2023-5tjnc | Catalytic performance of supported Ni in the hydrodesulfurization of dibenzothiophene | To reduce pollution, sulfur, nitrogen, and other heteroatoms are removed from fuels by hydrotreatment (HDT). Conventional HDT catalysts are based on Ni-MoS2 phases dispersed over -Al2O3. Despite the myriad of papers studying these catalysts, it is somehow surprising to learn that the role of Ni in these catalysts is not yet fully understood. Most literature considers that Ni is either converted to some form of catalytically inactive nickel sulfide or that it mixes with MoS2 to act as a strong catalytic promoter. In this work, we focused on analyzing whether well-dispersed supported nickel nanoparticles can be active in the hydrodesulfurization of dibenzothiophene; one of the most refractory molecules composing diesel and marine fuels. We dispersed nickel using the principles of the strong electrostatic adsorption (SEA) method over silica (~neutral acidity), Al2O3 (Lewis acidity), H+-Y zeolite (Brönsted-Lewis acidity), and microporous-mesoporous H+-Y zeolite (similar Brönsted-Lewis acidity than its microporous counterpart). The results showed that Ni nanoparticles are catalytically active in the hydrodesulfurization of DBT and that zeolites provide them with long-term stability. In addition, using SEA impregnation and providing mesoporosity to the zeolite improved the catalytic performance. Overall, we demonstrate that Ni nanoparticles may behave in the same manner as noble metals such as Pt, Pd, and Ir behave in hydrodesulfurization. We discuss some of the probable reasons for such behavior and remark on the role of Ni in hydrotreatment. | Rodrigo Valderrama-Zapata; Julieth T. García-Sánchez; Omar J. Vargas-Montañez; Sergio A. Rincón-Ortiz; Iván D. Mora-Vergara; David Pérez-Martínez; Edgar M. Morales-Valencia; Víctor Gabriel Baldovino Medrano | Materials Science; Catalysis; Chemical Engineering and Industrial Chemistry; Catalysts; Fuels - Materials; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-12-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/657cbbea66c138172946233f/original/catalytic-performance-of-supported-ni-in-the-hydrodesulfurization-of-dibenzothiophene.pdf |
60c740cb9abda29b84f8bd4b | 10.26434/chemrxiv.7841177.v1 | Beyond the Gouy-Chapman Model with Heterodyne-Detected Second Harmonic Generation | <p>We report ionic strength-dependent phase shifts in second harmonic generation (SHG) signals from charged interfaces that verify a recent model in which dispersion between the fundamental and second harmonic beams modulates observed signal intensities. We show how phase information can be used to unambiguously separate the chi(2) and interfacial potential-dependent chi(3) terms that contribute to the total signal and provide a path to test primitive ion models and mean field theories for the electrical double layer with experiments to which theory must conform. Finally, we demonstrate the new method on supported lipid bilayers and comment on the ability of our new instrument to identify hyper-Rayleigh scattering contributions to common homodyne SHG measurements in reflection geometries.</p> | Franz Geiger; Paul E. Ohno; HanByul Chang; Austin
P. Spencer; Mavis
D. Boamah; Liu, Yangdongliu; Wang, Hong-fei | Interfaces; Optics; Spectroscopy (Physical Chem.); Surface; Thermodynamics (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 1970-01-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c740cb9abda29b84f8bd4b/original/beyond-the-gouy-chapman-model-with-heterodyne-detected-second-harmonic-generation.pdf |
6751c1ba5a82cea2fa17595f | 10.26434/chemrxiv-2024-mf7f8 | The Role of Counterion Size in Defining Star-Shaped Polyelectrolytes Thermodynamics, Conformations, and Ion Dynamics | In this work, we systematically investigate the impact of counterion size on the behavior of star-shaped strong polyelectrolytes in dilute aqueous solutions using Langevin simulations and a primitive model of electrolytes. Varying both the counterion diameter and the number of arms of the polyelectrolyte, we demonstrated that both characteristics significantly impact polyelectrolyte conformations and counterions absorption. Counterions dynamics is also affected, the most interesting aspect being the presence of a fraction of mobile ions slowly diffusing, compared to the average behavior, which increases with polyelectrolyte branching and their size. Informed by the results on systems with single-size counterions, we also investigate possible changes in behavior of these polyelectrolytes when neutralized by a binary mixture of bulky and small counterions at different relative concentration. Our results show that small counterions demonstrate a greater tendency for remaining located within the inner regions of the polyelectrolyte, particularly when their molar fraction is low and the polyelectrolyte is highly branched. This results in the spatial separation of the two species into core-shell-like structures, which dramatically decreases the diffusivity of the smaller counterions. By investigating the partitioning of counterions between the solution and the regions internal to the polyelectrolytes, it is shown that the selectivity toward the smaller species can be significantly enhanced by increasing the number of arms and operating under conditions of counterion scarcity. | Andrea Tagliabue; Massimo Mella | Theoretical and Computational Chemistry; Physical Chemistry; Polymer Science; Polyelectrolytes - Polymers; Computational Chemistry and Modeling; Theory - Computational | CC BY NC 4.0 | CHEMRXIV | 2024-12-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6751c1ba5a82cea2fa17595f/original/the-role-of-counterion-size-in-defining-star-shaped-polyelectrolytes-thermodynamics-conformations-and-ion-dynamics.pdf |
645abd0bfb40f6b3ee4f0133 | 10.26434/chemrxiv-2023-rcbx6 | GiFE: A Molecular-Size Agnostic and Understandable Gibbs Free Energy Function | A fully defined and molecular-size agnostic Gibb’s free energy function that uses strictly structural parameters as input would permit real-time energetics determination and optimization of molecules heretofore intractable at ab initio levels. Here we present, the first part of a linear function for Gibbs free energy (GiFE Function) that covers the elements {H,N,O,C,F} and is molecular-size agnostic, using only atomic structure to generate the input variables. Critically, the GiFE function is capable not only of producing the value of Gibbs free energy for a given complex in constant time, but also may serve as a function over which molecules may be optimized in O(sqrt{n}) time. The prediction of individual and reaction free energies are demonstrated, as well as explanations of chemical understanding generated from the function and an outlining of how the rest of this function may be constructed, with examples covering {H,B,C,N,O,F,S,Si,Cl,Br,I}. | Jessica Freeze; Victor Batista | Theoretical and Computational Chemistry; Computational Chemistry and Modeling; Theory - Computational; Machine Learning | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/645abd0bfb40f6b3ee4f0133/original/gi-fe-a-molecular-size-agnostic-and-understandable-gibbs-free-energy-function.pdf |
64dddbcc4a3f7d0c0d4e934c | 10.26434/chemrxiv-2023-zblrz-v5 | Predicting nearest neighbor free energies of modified RNA with LIE: Results for pseudouridine and N1-methylpseudouridine within RNA duplexes | Pseudouridine and N1-methylpseudouridine are the key
modifications in the field of mRNA therapeutics and vaccine research. The accuracy of the design and development of therapeutic RNAs containing such modifications requires the accuracy of the secondary structure prediction, that depends on the nearest neighbor (NN) thermodynamic parameters for the standard and modified residues. The development of such NN thermodynamic parameters requires expensive and time-consuming experimental studies. There were some earlier attempts to predict the NN
free energies of modified RNA using computational methods but those are either computationally expensive or not accurate enough. Here, we propose a new protocol based on MD simulations, which is able to predict the NN free energy parameters (ΔG◦37) for U-A, Ψ-A and m1Ψ-A pairs in general agreement with the recent experimental reports. We report the NN thermodynamic parameters for different U, Ψ and m1Ψ base pairs, which might be helpful for a deeper understanding of the effect of these modifications in RNA. The presence of m1Ψ resulted
in more stable NN pairs compared to those containing U or Ψ. The predicted NN free energy parameters in this study are able to closely reproduce the folding free energies of duplexes containing internal Ψ for which the thermodynamic data were available. Additionally, we report
the predicted folding free energies for the duplexes containing internal m1Ψ. | Nivedita Dutta; Joanna Sarzynska; Indrajit Deb; Ansuman Lahiri | Theoretical and Computational Chemistry; Biological and Medicinal Chemistry; Computational Chemistry and Modeling; Theory - Computational; Chemoinformatics - Computational Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-08-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64dddbcc4a3f7d0c0d4e934c/original/predicting-nearest-neighbor-free-energies-of-modified-rna-with-lie-results-for-pseudouridine-and-n1-methylpseudouridine-within-rna-duplexes.pdf |
62fffa440c5277910cbb3b9e | 10.26434/chemrxiv-2022-1v9v6-v2 | Molecular Engineering of Fluoroether Electrolytes for Lithium Metal Batteries | Fluoroether solvents are promising electrolyte candidates for high-energy-density lithium metal bat- teries, where high ionic conductivity and oxidative stability are important metrics for design of new systems. Recent experiments have shown that these performance metrics, particularly stability, can be tuned by changing the fraction of ether and fluorine content. However, little is known about how different molecular architectures influence the underlying ion transport mechanisms and conductivity. Here, we use all-atom molecular dynamics simulations to elucidate the ion transport and solvation characteristics of fluoroether chains of varying length, and having different ether segment and flu- orine terminal group contents. The design rules that emerge from this effort are that solvent size determines lithium-ion transport kinetics, solvation structure, and solvation energy. In particular, the mechanism for lithium-ion transport is found to shift from ion hopping between solvation sites located in different fluoroether chains in short-chain solvents, to ion-solvent co-diffusion in long-chain solvents, indicating that an optimum exists for molecules of intermediate length, where hopping is possible but solvent diffusion is fast. Consistent with these findings, our experimental measurements reveal a non-monotonic behavior of the effects of solvent size on lithium-ion conductivity, with a maximum occurring for medium-length solvent chains. A key design principle for achieving high ionic conductivity is that a trade-off is required between relying on shorter fluoroether chains having high self-diffusivity, and relying on longer chains that increase the stability of local solvation shells. | Yuxi Chen; Elizabeth Lee; Phwey Gil; Peiyuan Ma; Chibueze Amanchukwu; Juan de Pablo | Materials Science; Energy; Chemical Engineering and Industrial Chemistry; Energy Storage | CC BY NC ND 4.0 | CHEMRXIV | 2022-08-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62fffa440c5277910cbb3b9e/original/molecular-engineering-of-fluoroether-electrolytes-for-lithium-metal-batteries.pdf |
6274253e44bdd574bd581c6a | 10.26434/chemrxiv-2022-1gjxb | Polymer-Bound Halogen Bonding Organocatalysis | Noncovalent organocatalysts utilizing halogen bonding have emerged in the last decade as efficient alternatives to more established hydrogen bonding donors. However, currently they often cannot be recycled and, in some cases, even stoichiometric amounts need to be used. Herein, we present the first generation of recyclable, polymer-bound halogen bonding catalysts which are able to catalyze a halide abstraction reaction. To this end, bis(benzimidazolium)-based halogen bonding units were attached to a polystyrene polymer, yielding insoluble catalysts. These could be recycled up to three times with little loss in catalytic activity. The overall performance of the catalysts is comparable to that of a free (non-polymer-bound) halogen bond donor. Interestingly, catalysts featuring a preorganized and a non-preorganized halogen bond donating unit showed comparable activity, in contrast to the situation of the free donors. This proof-of-principle study provides the basis for further steps towards more sustainable halogen bonding organocatalysts. | Raffaella Papagna; Dana Kutzinski; Stefan Huber | Organic Chemistry; Organic Synthesis and Reactions; Supramolecular Chemistry (Org.) | CC BY NC 4.0 | CHEMRXIV | 2022-05-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6274253e44bdd574bd581c6a/original/polymer-bound-halogen-bonding-organocatalysis.pdf |
63da9dfc01ecc690f91c39db | 10.26434/chemrxiv-2024-l39zx | Simulating Metal-Imidazole Complexes | One commonly observed binding motif in metalloproteins involves the interaction between a metal ion and histidine's imidazole sidechains. Although previous imidazole-M(II) parameters established the flexibility and reliability of the 12-6-4 Lennard-Jones (LJ)-type nonbonded model by simply tuning the ligating atom’s polarizability, they have not been applied to multiple-imidazole complexes. To fill this gap, we systematically simulate multiple-imidazole complexes (ranging from one to six) for five metal ions (Co(II), Cu(II), Mn(II), Ni(II), and Zn(II)) which commonly appear in metalloproteins. Using extensive (40ns per PMF window) sampling to assemble free energy association profiles (using OPC water and standard HID imidazole charge models from AMBER) and comparing them to DFT calculations, a new set of parameters was developed to focus on energetic and geometric features of multiple-imidazole complexes. The obtained free energy profiles agree with the experimental binding free energy and DFT calculated distances. Further investigation of the simulations revealed the existence of ligand-ligand hydrogen bonds and partial π-stacking while one ligand dissociates from the complex. To validate our model, we show that we can close the thermodynamic cycle for metal-imidazole complexes with up to six imidazole molecules in the first solvation shell. Given the success in closing the thermodynamic cycles, we then used the same extended sampling method for six other metal ions (Ag(I), Ca(II), Cd(II), Cu(I), Fe(II), and Mg(II)) to obtain new parameters. Since these new parameters can reproduce the one-imidazole geometry and energy accurately, we hypothesize that they will reasonably predict the binding free energy of higher-level coordination numbers. Hence, we did not extend the analysis of these ions up to six imidazole complexes. Overall, the results shed light on metal-protein interactions by emphasizing the importance of ligand-ligand interaction and metal-π-stacking within metalloproteins. | Zhen Li; Subhamoy Bhowmik; Luca Sagresti; Guiseppe Brancato; Madelyn Smith; David Benson; Pengfei Li; Kenneth Merz | Physical Chemistry; Physical and Chemical Properties | CC BY NC ND 4.0 | CHEMRXIV | 2024-05-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63da9dfc01ecc690f91c39db/original/simulating-metal-imidazole-complexes.pdf |
628fe9219a0ad58dc41576b2 | 10.26434/chemrxiv-2022-q01tz | Iodine–Iodine Cooperation Enables Metal-Free C–N Bond-Forming Electrocatalysis via Isolable Iodanyl Radicals | Small molecule redox mediators convey interfacial electron transfer events into bulk solution and can enable diverse substrate activation mechanisms in synthetic electrocatalysis. Here we report that 1,2-diiodo-4,5-dimethoxybenzene (1a) is an efficient electrocatalyst for C-H/E-H coupling that operates at as low as 0.5 mol% catalyst loading. Spectroscopic, crystallographic, and computational results indicate a critical role for a three-electron I-I bonding interaction in stabilizing an iodanyl radical intermediate (i.e., formally I(II) species). As a result, 1a operates at more than 100 mV lower potential than related monoiodide catalysts, which results in improved product yield, higher Faradaic efficiency, and expanded substrate scope. The isolated iodanyl radical is chemically competent in C-N bond formation. These results represent the first examples of substrate functionalization at a well-defined I(II) derivative and bona fide iodanyl radical ca-talysis and demonstrate one-electron pathways as a mechanistic alternative to canonical two-electron hypervalent iodine mechanisms. The observation establishes I-I redox cooperation as a new design concept for the development of metal-free redox mediators. | Brandon Frey; Matthew Figgins; Gerard Van Trieste; Raanan Carmieli; David Powers | Organic Chemistry; Catalysis; Electrocatalysis; Homogeneous Catalysis; Redox Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2022-05-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/628fe9219a0ad58dc41576b2/original/iodine-iodine-cooperation-enables-metal-free-c-n-bond-forming-electrocatalysis-via-isolable-iodanyl-radicals.pdf |
651cce308bab5d20559a3f0e | 10.26434/chemrxiv-2023-30dtw | 14N to 15N Isotopic Exchange of Nitrogen Heteroaromatics through Skeletal Editing | The selective modification of nitrogen heteroaromatics enables the development of new chemical tools and accelerates drug discovery. While methods that focus on expanding or contracting the skeletal structures of heteroaromatics are emerging, methods for the direct exchange of single core atoms remain limited. Here, we present a method for 14N → 15N isotopic exchange for several aromatic nitrogen heterocycles. This nitrogen isotope transmutation occurs through activation of the heteroaromatic substrate by triflylation of a nitrogen atom, followed by a ring-opening/ring-closure sequence mediated by 15N-aspartate to effect isotopic exchange of the nitrogen atom. Key to the success of this transformation is the formation of an isolable 15N-succinyl intermediate, which undergoes elimination to give the isotopically labeled heterocycle. These transformations occur under mild conditions in high chemical and isotopic yields. | G. Logan Bartholomew; Samantha L. Kraus; Lucas J. Karas; Filippo Carpaneto; Raffeal Bennett; Matthew S. Sigman; Charles S. Yeung; Richmond Sarpong | Organic Chemistry; Organic Synthesis and Reactions | CC BY 4.0 | CHEMRXIV | 2023-10-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/651cce308bab5d20559a3f0e/original/14n-to-15n-isotopic-exchange-of-nitrogen-heteroaromatics-through-skeletal-editing.pdf |
63868ba86b4e81060e845710 | 10.26434/chemrxiv-2022-x1z2l | QM/MM Simulations on NVIDIA and AMD GPUs | We have ported and optimized the GPU accelerated QUICK and AMBER based ab initio QM/MM implementation on AMD GPUs. This encompasses the entire Fock matrix build and force calculation in QUICK including one-electron integrals, two-electron repulsion integrals, exchange-correlation quadrature, and linear algebra operations. General performance improvements to the QUICK GPU code are also presented. Benchmarks carried out on NVIDIA V100 and AMD MI100 cards display similar performance on both hardware for standalone HF/DFT calculations with QUICK and QM/MM molecular dynamics simulations with QUICK/AMBER. Furthermore, with respect to the QUICK/AMBER release version 21, significant speedups are observed for QM/MM molecular dynamics simulations. This significantly increases the range of scientific problems that can be addressed with open-source QM/MM software on state-of-the-art computer hardware. | Madushanka Manathunga ; Hasan Metin Aktulga; Andreas W. Goetz; Kenneth M. Merz, Jr | Theoretical and Computational Chemistry; Theory - Computational | CC BY 4.0 | CHEMRXIV | 2022-11-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63868ba86b4e81060e845710/original/qm-mm-simulations-on-nvidia-and-amd-gp-us.pdf |
60c74413567dfe84e3ec420b | 10.26434/chemrxiv.9736385.v1 | Mechanism of Dissociation Kinetics in Polyelectrolyte Complex Micelles | <div>
<div>
<p>Polyelectrolyte-based nanoscale self-assemblies, such as micelles, possess diverse desirable attributes such as capability for sequestering and protecting biomacromolecules against inhospitable environments, responsiveness to external stimuli, and tunability of physical behavior. However, little is known on the mechanisms of dissociation when micelles encounter and respond to environmental changes. Using salt-jump, time-dependent, light scattering, the pathway of dissociation is observed in polyelectrolyte complex micelles that have complex cores and neutral coronas. The micelle dissociation kinetics appear to be a three-staged process, in good agreement with the scattering data. Using kinetic models of amphiphilic block copolymer micelles in polyelectrolyte complexation-driven micelles, we derive an analytical expression for dissociation relaxation rates as a function of solvent temperature, salt concentration, and the length of the charged polymer blocks. The theoretical predictions are compatible with the experimental data from light scattering experiments. This study demonstrates experimentally the relaxation kinetics of polyelectrolyte complex micelle dissociation and illustrates the underlying mechanism governing the dissociation kinetics. It is anticipated that these findings can be generalized to other electrostatic interaction-driven self-assemblies to better understand the relationship among the kinetics of dissociation, constituent polymer properties, and environmental parameters.<br /></p>
</div>
</div> | Hao Wu; Jeffrey Ting; Matthew Tirrell | Polyelectrolytes - Polymers; Polymer chains; Polymerization kinetics; Polymer morphology | CC BY NC ND 4.0 | CHEMRXIV | 2019-08-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74413567dfe84e3ec420b/original/mechanism-of-dissociation-kinetics-in-polyelectrolyte-complex-micelles.pdf |
64ce4ccbdfabaf06ffc2c719 | 10.26434/chemrxiv-2023-zrcgd | Development of an Efficient Thionolactone for Radical Ring-Opening Polymerization by a Combined Theoretical/Experimental Approach | The environmental impact of plastic waste has been a real problem for the past decades. The incorporation of cleavable bonds in the polymer backbone is a solution to make a commodity polymer degradable. When radical polymerization is used, this approach is made possible by the radical ring-opening polymerization (rROP) of a cyclic monomer that allows the introduction of a weak bond into the polymer backbone. Among the various cyclic monomers that could be used in rROP, thionolactones are promising structures due to the efficiency of the C=S bond to act as radical acceptor. Nevertheless, only few structures were reported to be efficient. In this work, we used DFT calculations to gain better understanding of the radical reactivity of thionolactones and in particular we focused on the transfer rate constant ktr value and its ratio with the propagation rate constant kp of the vinyl monomer. The closer to 1, the better the statistical incorporation of the two comonomers into the backbone. With this approach, we identified and prepared the 7-phenyloxepane-2-thione (POT) thionolactone. The copolymerization of styrene and various acrylate derivatives with POT led to statistical copolymers that were efficiently degraded under accelerated conditions (KOH in THF/MeOH, TBD in THF or mCPBA in THF), confirming the theoretical approach. The compatibility with RAFT polymerization was established as well as the homopolymerization behavior of POT. This theoretical approach paves the way to the in-silico design of new efficient thionolactones for rROP | Bastien Luzel; Noémie Gil; Patrick Désirée; Julien Monot; Didier Bourissou; Didier Siri; Didier Gigmes; Blanca Martin-Vaca; Catherine Lefay; Yohann Guillaneuf | Polymer Science; Organic Polymers; Polymerization (Polymers); Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2023-08-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64ce4ccbdfabaf06ffc2c719/original/development-of-an-efficient-thionolactone-for-radical-ring-opening-polymerization-by-a-combined-theoretical-experimental-approach.pdf |
65f635fde9ebbb4db9da8a04 | 10.26434/chemrxiv-2024-2l83x | Organo-Photoredox Catalyzed gem-Difluoroallylation of Ketones via C(sp3)-C Bond and C(sp3)-F bond Cleavage | An organo-photoredox catalyzed gem-difluoroallylation of both acyclic and cyclic ketone derivatives with α-trifluoromethyl alkenes has been demonstrated, thus giving access to a diverse set of gem-difluoroalkenes in moderate to high yields. Pro-aromatic dihy-droquinazolinones can be either pre-formed or in situ generated for ketone activation. This reaction is characterized by readily available starting materials, mild reaction conditions, and broad substrate scope. The feasibility of this reaction has been highlighted by the late-stage modification of several natural products and drug-like molecules as well as the antifungal activity. | Yue Zhang; Tianshuai Zhu; Xian Wei; Yuqian Lin; Ruofan Lin; Zhijie Zhang; Weiwei Fang; Jing-Jing Zhang; Yue Zhang; Meng-Yang Hu; Zhen Chen | Organic Chemistry | CC BY 4.0 | CHEMRXIV | 2024-03-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65f635fde9ebbb4db9da8a04/original/organo-photoredox-catalyzed-gem-difluoroallylation-of-ketones-via-c-sp3-c-bond-and-c-sp3-f-bond-cleavage.pdf |
6668689e409abc034528c5bd | 10.26434/chemrxiv-2024-1csjw | Electrolytic Conversion of Nitro Compounds into Amines in a Membrane Reactor | Aromatic and aliphatic amines are key intermediates in the synthesis of pharmaceuticals, dyes, and agrochemicals. These amines are often sourced from nitro compounds. The hydrogenation of nitro compounds into amines requires harsh reaction conditions (e.g., high pressures and/or high temperatures) or additives that are usually toxic. Here we demonstrate hydrogenation of nitro compounds into amines in the hydrogenation compartment of a membrane reactor. The hydrogen is sourced from water in an adjacent electrolysis compartment, separated by a hydrogen-permeable palladium membrane. Modifications of the palladium membrane with catalysts enabled a wide range of commercially relevant nitro compounds to be hydrogenated into amines without any additives at ambient pressure and room temperature. This membrane reactor also enables nitro hydrogenation to occur at high concentrations and with high functional group tolerance. | Arijit Singha Hazari; Marvin Frisch; Yunzhou Wen; Mia Stankovic; Curtis Berlinguette | Organic Chemistry; Inorganic Chemistry; Catalysis; Electrochemistry; Electrocatalysis; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-06-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6668689e409abc034528c5bd/original/electrolytic-conversion-of-nitro-compounds-into-amines-in-a-membrane-reactor.pdf |
60c752c20f50dba240397a24 | 10.26434/chemrxiv.13342208.v1 | Thermal Conductivity of PDMS Filled with Hollow Glass Microspheres | Polydimethylsiloxane (PDMS) is the most widely used
silicon-based polymer due to its versatility and the range of attractive properties.
Fabrication
of PDMS involves liquid phase cross-linking to obtain hydrophobic and
mechanically flexible material in the final solid form. This gives opportunity
to add various fillers to affect the properties of resulting material. In the
present work, we describe simple and
reliable method of making a PDMS-based composite material with significantly
improved thermal insulation properties by adding hollow glass microspheres
(HGMs) to the mixture of liquid base and cross-linker (10:1 ratio) followed by
degassing and heat-assisted crosslinking. We obtained 31% reduction of thermal
conductivity for samples with HGMs content of 20% by mass. At the same time, sound insulation capacity
slightly decreased as a result of lower density of PDMS-HGMs composite in
comparison to pure PDMS. The wettability of the samples had no dependence on
HGMs content. | Sergei Vlassov; Sven Oras; Martin Timusk; Vahur Zadin; Ilja Sosnin; Rünno Lõhmus; Leonid
M. Dorogin | Composites; Thermal Conductors and Insulators | CC BY NC ND 4.0 | CHEMRXIV | 2020-12-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c752c20f50dba240397a24/original/thermal-conductivity-of-pdms-filled-with-hollow-glass-microspheres.pdf |
6506afdbb6ab98a41c98a71d | 10.26434/chemrxiv-2023-214k8 | Unfolding Potential of Click Chemistry in
Bioconjugation: A Review | The application of click chemistry, specifically Copper-Catalyzed Azide-Alkyne Cycloaddition (CuAAC)
and Strain-Promoted Azide-Alkyne Cycloaddition (SPAAC), in bioconjugation has shown tremendous
promise in various biomedical fields. This comprehensive review aims to dissect and explore the
significant potential of these click chemistry techniques in bioconjugation. We begin by discussing the
fundamental principles and advantages of CuAAC and SPAAC in bioconjugation, emphasizing their
unique kinetics, biocompatibility, and selectivity. The paper then navigates the landscape of current
research, identifying emerging trends and proposing prospective paths for the application of click
chemistry in bioconjugation. We focus on the broad applicability of these techniques in diagnostics,
imaging, and therapeutic strategies, including the construction of antibody-drug conjugates, the creation
of prodrugs, and the design of targeted drug delivery systems. The review concludes by projecting an
optimistic future for click chemistry in bioconjugation, indicating its potential to revolutionize
personalized medicine, tissue engineering, and even branches of environmental science and
sustainability. We weave our analysis with the latest scholarly research, providing substantial backing to
our findings and potential directions for future exploration. | Fathima Shadin P | Biological and Medicinal Chemistry; Nanoscience; Nanodevices; Nanostructured Materials - Nanoscience; Drug Discovery and Drug Delivery Systems; Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2023-09-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6506afdbb6ab98a41c98a71d/original/unfolding-potential-of-click-chemistry-in-bioconjugation-a-review.pdf |
60c74f23f96a00287d287bd5 | 10.26434/chemrxiv.12818174.v1 | The Catalytic Mechanics of Dynamic Surfaces: Stimulating Methods for Promoting Catalytic Resonance | Transformational catalytic performance in rate and selectivity is obtainable through catalysts that change on the time scale of catalytic turnover frequency. In this work, dynamic catalysts are defined in the context and history of forced and passive dynamic chemical systems, with classification of unique catalyst behaviors based on temporally-relevant linear scaling parameters. The conditions leading to catalytic rate and selectivity enhancement are described as modifying the local electronic or steric environment of the active site to independently accelerate sequential elementary steps of an overall catalytic cycle. These concepts are related to physical systems and devices that stimulate a catalyst using light, vibrations, strain, and electronic manipulations including electrocatalysis, back-gating of catalyst surfaces, and introduction of surface electric fields via solid electrolytes and ferroelectrics. These catalytic stimuli are then compared for capability to improve catalysis across some of the most important chemical challenges for energy, materials, and sustainability. | Manish Shetty; Amber Walton; Sallye R. Gathmann; M. Alexander Ardagh; Joshua Gopeesingh; Joaquin Resasco; Turan Birol; Qi Zhang; Michael Tsapatsis; Dionisios Vlachos; Phillip Christopher; C. Daniel Frisbie; Omar Abdelrahman; Paul Dauenhauer | Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2020-08-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74f23f96a00287d287bd5/original/the-catalytic-mechanics-of-dynamic-surfaces-stimulating-methods-for-promoting-catalytic-resonance.pdf |
665b7f8b91aefa6ce18f6048 | 10.26434/chemrxiv-2024-nkbbj | Unique structure type and antiferromagnetic ordering in semiconducting Eu2InSnP3 | The multitude of bonding motifs that can arise from the main group elements in pnictides leads to ternary compounds with rare earths that span insulating and metallic behavior, layered and channeled compounds, and ferrimagnetic and antiferromagnetic ordering. Here we present the quaternary pnictide Eu2InSnP3, which forms in the orthorhombic space group Pnma. The Eu2+ ions in Eu2InSnP3 form a hollandite-like channeled matrix of edge-sharing EuP6 octahedra, while the interior of the channels are filled with ethane-like InSnP6 units. Despite the challenges in differentiating In and Sn by X-ray diffraction, their equimolar concentration and ordering in this compound is enforced by the need for charge balance, which leads to semiconducting behavior. First-principles simulations confirm the stability of the experimentally found crystal structure and show that the smallest gap to be indirect of about 0.5 eV, but close in energy to a direct gap. The magnetic behavior of Eu2InSnP3 is complex, with a low-field antiferromagnetic ordering at TN = 12 K and a spin-flop transition around 0.8 T at 2 K. The progression of magnetic states is complex, driven by the two inequivalent Eu sites in the compound and the low anisotropy of the 4f7 Eu ion. | Mebatsion Gebre; Zhihao Jiang; Zachary Riedel; Emma Pappas; Honghui Zhou; Andre Schleife; Daniel Shoemaker | Materials Science; Magnetic Materials; Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2024-06-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/665b7f8b91aefa6ce18f6048/original/unique-structure-type-and-antiferromagnetic-ordering-in-semiconducting-eu2in-sn-p3.pdf |
660172529138d231613f9a5b | 10.26434/chemrxiv-2024-kq54d | Light-induced quantum reconfiguration of oxyhydroxides
for photoanodes with 4.24% efficiency and stability beyond 250 hours | Photoelectrochemical (PEC) water splitting is attracting significant research interest in addressing sustainable development goals in renewable energy for the future. Current state-of-the-art, however, cannot provide photoanodes with simultaneously high efficiency and long-lasting device lifetime. Here, we report a large-scale NiFe oxyhydroxides-alloy hybridized cocatalyst layer on photoanodes that exhibit a record value of applied bias photon-to-current efficiency (ABPE) of 4.24% in buried homojunction-free photoanodes and stability over 250 hours with above 88% retention of the initial current density. These performances represent an increase over the present highest-performing technology by 408% in stability and the
most stable competitor by over 330% in efficiency in alkaline media. These results originate from a previously unexplored mechanism of light-induced atomic reconfiguration and surface amorphization in NiFe-based materials. This process self-generates at low biases and, in short times, a catalytic-protective amorphous/crystalline heterostructure that provides abundant highly catalytic active sites for reaction and insulates the photoanode from performance degradation. NiFe oxyhydroxides generated by photons are more than 200% higher than the quantity that pure electrocatalysis would otherwise induce, overcoming the threshold for an efficient oxygen reduction reaction in the device. While of immediate interest in the industry of water splitting, the light-induced NiFe oxyhydroxides-alloy co-catalyst developed in this work provides a general strategy to enhance further the performances and stability of PEC devices for a vast panorama of chemical reactions, ranging from biomass valorization to organic waste degradation, and CO2-to-fuel conversion. | Fei Xiang; Ning Li; Arturo Burguete-Lopez; Zhao He; Maxim Elizarov; Andrea Fratalocchi | Catalysis; Nanoscience; Energy; Nanocatalysis - Catalysts & Materials; Nanostructured Materials - Nanoscience; Photocatalysis | CC BY 4.0 | CHEMRXIV | 2024-03-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/660172529138d231613f9a5b/original/light-induced-quantum-reconfiguration-of-oxyhydroxides-for-photoanodes-with-4-24-efficiency-and-stability-beyond-250-hours.pdf |
64f11da63fdae147fa38f7b5 | 10.26434/chemrxiv-2023-347gr-v2 | Modular solar-to-fuels electrolysis at low cell potentials enabled by glycerol electrooxidation and a bipolar membrane separator | Solar fuel generation through water electrolysis or electrochemical CO2 reduction is thermodynamically limited when paired with the oxygen evolution reaction (OER). The glycerol electrooxidation reaction (GEOR) is an alternative anodic reaction with lower anodic electrochemical potential that utilizes a renewable coproduct produced during biodiesel synthesis. We show that GEOR on a Au-Pt-Bi ternary metal electrocatalyst in a model alkaline crude glycerol solution can provide significant cell potential reductions even when paired to reduction reactions in seawater and acidic catholytes via a bipolar membrane (BPM). We showed that the combination of GEOR electrooxidation and a BPM separator lowers the total cell potential by 1 V at an electrolysis current of 10.0 mA cm-2 versus to an anode performing OER when paired with hydrogen evolution and CO2 reduction cathodes. The observed voltage reduction was steady for periods of up to 80 hours, with minimal glycerol crossover observed through the membrane. These results motivate new, high-performance cell designs for photoelectrochemical solar fuels integrated systems based on glycerol electrooxidation. | Hamed Mehrabi; Zebulon Schichtl; Samuel Conlin; Robert Coridan | Materials Science; Catalysis; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2023-09-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64f11da63fdae147fa38f7b5/original/modular-solar-to-fuels-electrolysis-at-low-cell-potentials-enabled-by-glycerol-electrooxidation-and-a-bipolar-membrane-separator.pdf |
67a121d981d2151a02124caf | 10.26434/chemrxiv-2025-m3085 | Evolution of Dirac Nodal Arc Surface States as the Electronic Engine of Alkaline HER on Oxide-Free PtSn4 Surface | Dirac nodal arc semimetal PtSn4 has been experimentally shown to be a promising catalyst for the hydrogen evolution reaction (HER) owing to its reduced consumption of the precious metal and low overpotential. The catalytic activity of PtSn4 has been hypothetically attributed to the topologically protected surface states when the surface remains unoxidized. However, the specific involvement of its topological surface states in the HER process remains to be fully elucidated, and it is indeed in question if the topological nature of this alloy is catalytically consequential. This study stands upon the viewpoint of topological catalysis and reveals the evolution of the PtSn4 surface states within an alkaline HER cycle from first principles. We show that Sn vacancies on the pristine Sn-terminated (010) surface result in a reconstructed surface exposing both the Pt and Sn atoms. Such a reconstruction is supported by the excellent agreement between the simulated and the experimental scanning tunneling microscopy images. Hydrides then form on this surface as the resting state of the catalyst. As hydrogen atoms bind to the surface, the topologically protected Dirac node surface
states respond to further reconstructions, splitting into two surface bands near the Fermi level. Through band structure and wavefunction analysis, we highlight three key surface states: initial bonding state, reserved bonding state, and antibonding state. They are responsible for driving the HER cycle through interacting with the incoming hydrogen in various stages. Despite the major perturbation created by the reaction conditions, the surface bands form a stable configuration, serving consistently as the frontier states. Thus, the topological protection allows the Dirac node surface states to be an active and evolving driver of HER catalysis on PtSn4. Our findings provide detailed evidences for the direct participation of nontrivial surface states in HER on PtSn4 when utilized as a topological catalyst. | Guorong Weng; Anastassia N. Alexandrova | Theoretical and Computational Chemistry; Catalysis; Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2025-02-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67a121d981d2151a02124caf/original/evolution-of-dirac-nodal-arc-surface-states-as-the-electronic-engine-of-alkaline-her-on-oxide-free-pt-sn4-surface.pdf |
60c73d76842e657d1edb1795 | 10.26434/chemrxiv.5826435.v1 | Influence of intramolecular interactions on carbon dioxide gas adsorption capacity in Mesoporous Imine polymers | <p>Covalent
organic Imine polymers with intrinsic meso-porosity were synthesized by
condensation reaction between 4,4-diamino diphenyl methane and (para/meta/ortho)-phthaladehyde.
Even though these polymers were synthesized from precursors of bis-bis covalent
link mode, the bulk materials were micrometer size particles with intrinsic
mesoporous enables nitrogen as well as carbon dioxide adsorption in the void
spaces. These polymers were showed stability up to 260<sup>o</sup> centigrade.
Nitrogen gas adsorption capacity up to 250 cc/g in the ambient pressure was observed
with type III adsorption characteristic nature. Carbon dioxide adsorption
experiments reveal the possible terminal amine functional group to carbamate with
CO<sub>2</sub> gas molecule to the polymers. One of the imine polymers, COP-3
showed more carbon dioxide sorption capacity and isosteric heat of adsorption
(Q<sub>st</sub>) than COP-1 and COP-2 at 273 K even though COP-3 had lower
porosity for nitrogen gas than COP-1 and COP-2. We explained the trends in gas
adsorption capacities and Qst values as a consequence of the intra molecular
interactions confirmed by Density Functional Theory computational experiments
on small molecular fragments.</p> | Jaya Prakash Madda; Pilli Govindaiah; Sushant Kumar Jena; Sabbhavat Krishna; Rupak Kishor | Physical and Chemical Properties | CC BY NC ND 4.0 | CHEMRXIV | 2018-01-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73d76842e657d1edb1795/original/influence-of-intramolecular-interactions-on-carbon-dioxide-gas-adsorption-capacity-in-mesoporous-imine-polymers.pdf |
642ef0600784a63aeea6b1ae | 10.26434/chemrxiv-2023-qg7zx | Curing-Induced Residual Stress and Strain in Thermoset
Composites | Uncontrolled curing-induced residual stress and strain are significant limitations to the efficient design of thermoset composites that compromise their structural durability and geometrical tolerance. Experimentally validated
process modeling for the evaluation of processing parameter contributions to the residual stress build-up is crucial to identify residual stress mitigation strategies and enhance structural performance. This work presents an
experimentally validated novel numerical approach based on higher-order finite elements for the process modeling of fiber-reinforced thermoset polymers across two composite characteristic length scales, the micro and
macro-scale levels. The cure kinetics is described using an auto-catalytic phenomenological model. An instantaneous linear-elastic constitutive law, informed by time-dependent material characterization, is used to evaluate
the stress state evolution as a function of the degree of cure and time. Micromechanical modeling is based on
Representative Volume Elements (RVEs) that account for random fiber distribution verified against traditional
3D FE analysis. 0/90 laminate testing at the macroscale validates the proposed approach with an accuracy of
9%. | Manish Nagaraj; Marianna Maiaru | Materials Science; Polymer Science; Composites; Materials Processing; Polymerization (Polymers) | CC BY NC ND 4.0 | CHEMRXIV | 2023-04-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/642ef0600784a63aeea6b1ae/original/curing-induced-residual-stress-and-strain-in-thermoset-composites.pdf |
60c7455e4c8919cc8cad2990 | 10.26434/chemrxiv.10007291.v1 | Chiral Tetrahydropyridines via FeCl3-Catalyzed Carbonyl-Olefin Metathesis | <div>
<div>
<p>Herein, we describe the application of Lewis acid-catalyzed
carbonyl-olefin metathesis towards the synthesis of chiral, substituted
tetrahydropyridines from commercially available amino acids as chiral pool
reagents. This strategy relies on FeCl<sub>3</sub> as an inexpensive and
environmentally benign catalyst and enables access to a variety of substituted
tetrahydropyridines under mild reaction conditions. The reaction proceeds with
complete stereoretention and is viable for a variety of natural and unnatural
amino acids to provide the corresponding tetrahydropyridines in up to 99% yield.</p>
</div>
</div>
<br /> | Katie Rykaczewski; Emilia
J. Groso; Hannah L. Vonesh; Mario Gaviria; Alistair D. Richardson; Troy E. Zehnder; Corinna Schindler | Acid Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2019-10-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7455e4c8919cc8cad2990/original/chiral-tetrahydropyridines-via-fe-cl3-catalyzed-carbonyl-olefin-metathesis.pdf |
645e1451fb40f6b3ee759825 | 10.26434/chemrxiv-2023-6crbr | Quantitative Assays for Catalytic Photo-Oxygenation of Alzheimer Disease-Related Tau Proteins | Catalytic photo-oxygenation of tau amyloid is a potential therapeutic approach to tauopathies, including Alzheimer dis-ease (AD). However, tau is a complex target containing great molecular size and heterogeneous isoforms/proteoforms. Although catalytic photo-oxygenation has been confirmed when using catalyst 1 and recombinant tau pretreated with heparin, its effects on tau from human patients have not yet been clarified. In this study, focusing on the histidine resi-dues being oxygenated, we have constructed two assay systems capable of quantitatively evaluating the catalytic activity when used on human patient tau: (1) fluorescence labeling at oxygenated histidine sites and (2) LC-MS/MS analysis of histidine-containing fragments. Using these assays, we identified 2 as a promising catalyst for oxygenation of human tau. In addition, our results suggest that aggregated tau induced by heparin is different from actual AD patient tau in develop-ing effective photo-oxygenation catalysts. | Hiroki Umeda; Taka Sawazaki; Masahiro Furuta; Takanobu Suzuki; Shigehiro Kawashima; Harunobu Mitsunuma; Yukiko Hori; Taisuke Tomita; Youhei Sohma; Motomu Kanai | Biological and Medicinal Chemistry; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/645e1451fb40f6b3ee759825/original/quantitative-assays-for-catalytic-photo-oxygenation-of-alzheimer-disease-related-tau-proteins.pdf |
65e0d0f066c1381729de3b54 | 10.26434/chemrxiv-2024-x6hxn | Development of an automated platform for monitoring microfluidic reactors through multi-reactor integration and online (chip-)LC/MS-detection | This work presents a novel microfluidic screening setup with real-time analytics for investigating reactions with immobilised biocatalysts. The setup combines microreactor technology, multi-reactor integration, and online (chip-)LC/MS analysis in a sequential automated workflow. We utilized in-house manufactured fused-silica glass chips as reusable packed-bed microreactors interconnected as individual tube reactors. The potential of this setup was showcased by conducting and optimising a biocatalytic aromatic bromination reaction as the first proof of concept using immobilised vanadium-dependent haloperoxidase from Curvularia inaequalis (CiVHPO). The fusion of a HaloTagTM to CiVHPO was used for efficient and mild covalent linkage of the enzyme onto chloroalkane-functionalized particles. Then, the biotransformation was continuously monitored with automated LC/MS data acquisition in a data-rich manner. By further developing the automation principle, it was possible to sequentially screen multiple different connected packed-bed microreactors for reaction optimization while using only miniature amounts of reactants and biocatalyst. Finally, we present a fast and modular chipHPLC solution for online analysis to reduce the overall solvent consumption by over 80%. We established a modern microfluidic platform for real-time reaction monitoring and evaluation of biocatalytic reactions through automation of the reactant feed integration, flexible microreactor selection, and online LC/MS analysis. | Hannes Westphal; Simon Schmidt; Sanjay Lama; Matthias Polack; Chris Weise; Toni Oestereich; Rico Warias; Tanja Gulder; Detlev Belder | Organic Chemistry; Analytical Chemistry; Bioorganic Chemistry; Organic Synthesis and Reactions; High-throughput Screening | CC BY 4.0 | CHEMRXIV | 2024-03-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65e0d0f066c1381729de3b54/original/development-of-an-automated-platform-for-monitoring-microfluidic-reactors-through-multi-reactor-integration-and-online-chip-lc-ms-detection.pdf |
624570a63b5f9902abca84e9 | 10.26434/chemrxiv-2021-ghnkr-v7 | Enzyvitands: versatile evolvable colorimetric chembioreceptors | Designing the perfect sensor is the dream of any chemist. Since decades, a wide variety of synthetic receptors that targets analytes have been explored in chemistry. Their chemical optimisation is hard and does not guarantee success. In this context, we propose a fast and self-assembling colorimetric bio-chemical receptor coined Enzyvitand. It consists of only commercial chemicals and relies on the reunification of combinatorial chemistry, interactions of first and second coordination spheres interactions and indicators displacement assays that are harboured within a protein cavity. The sensor is highly modular, cheap and evolvable. Owing to it's solved X-ray structure and docking studies, we rationally designed it for the selective naked-eye recognition of dopamine over other neurotransmitters through the second coordination sphere. The supramolecular-anchored boronic acid into the protein allows also discrimination between (D)-Fructose versus dopamine relying on second coordination sphere. Hence, our sensor imitates a biological receptor for the recognition of neurotransmitters. Finally, it works in complex samples such as urine. Its immediate high versatility and evolvability are valuable for the selective detection of a wide assortment of analytes, ranging from small molecules up to micro-organisms. Regarding future applications, we anticipate new biotechnological or immunotherapeutic applications of our synthetic oligomer. | Thibaud Rossel; zhang Bing; Raphael Gobat | Biological and Medicinal Chemistry; Bioengineering and Biotechnology; Chemical Biology; Drug Discovery and Drug Delivery Systems | CC BY NC ND 4.0 | CHEMRXIV | 2022-03-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/624570a63b5f9902abca84e9/original/enzyvitands-versatile-evolvable-colorimetric-chembioreceptors.pdf |
6512c5b1ade1178b2425a0eb | 10.26434/chemrxiv-2023-rlmhl | Chemical Analysis and Flavour Distribution of Electronic Cigarettes in Australian Schools | Introduction: Adolescent usage of electronic cigarettes has increased globally. Inconsistent, or absent, labelling of nicotine and other ingredients requires chemical analysis to accurately determine the chemical composition of these products.
Methods: Electronic cigarettes confiscated from public and private high school students (N=598) were provided for analysis from three regions in New South Wales, Australia. The products were examined for brand, model and flavour and a subset were further analysed for chemical composition (n=410) quantifying nicotine, synthetic cooling agents, flavouring chemicals and prohibited ingredients by gas chromatography-mass spectrometry (GC-MS).
Results: The majority of samples provided were fruity-flavoured disposable e-cigarettes across three main brands (IGET, HQD and Gunnpod). Nicotine was quantified in 97.3% of disposable samples with an average concentration of 40.0 mg/mL while one refill e-liquid was found to contain nicotine at a low concentration. Almost all samples contained the coolant WS-23 in relatively high concentrations compared to other flavouring chemicals present. Chemicals prohibited under the TGO110 (Australian e-cigarette product standard) were identified in 3.4% of the samples which were chemically analysed. This included the presence of ethylene glycol in moderately high concentrations (up to 13.2 mg/mL).
Conclusions: Australian students’ preferences for fruity, disposable e-cigarettes were identified regardless of region with the vast majority containing high concentrations of nicotine. WS-23 was found in most disposable e-cigarettes, potentially to reduce the throat irritation from nicotine and other flavouring chemicals. The inhalational safety of the samples is of concern due to health risks associated with detected prohibited compounds, particularly ethylene glycol.
| Caitlin Jenkins; Fraser Powrie; Celine Kelso; Jody Morgan | Analytical Chemistry; Analytical Chemistry - General; Mass Spectrometry; Separation Science | CC BY NC ND 4.0 | CHEMRXIV | 2023-09-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6512c5b1ade1178b2425a0eb/original/chemical-analysis-and-flavour-distribution-of-electronic-cigarettes-in-australian-schools.pdf |
60c74feb842e65295fdb3910 | 10.26434/chemrxiv.12959885.v1 | Polyvinylidene Difluoride: A Universal Binder for Preparation of Solid Phase Microextraction Devices | <p>The communication describes the application of a fluorocarbon-based polymer as a high performance binder component for coatings suitable for a variety of solid phase microextraction (SPME) configurations. SPME devices are characterized by their ability to perform physicochemical extraction of chemical compounds from a given sample, rending said chemical compounds suitable for instrumental determinations; fundamentally speaking, physiochemical extraction is accomplished by thermodynamic equilibrium driven by diffusion and partitioning of chemical compounds. A polyvinylidene difluoride (PVDF) polymer was used to immobilize various sorbent particles on different supports to create different formats of SPME, namely fiber, thin-film membrane, and CBS devices. In this report, PVDF-based coatings are introduced as universal SPME coatings that are amenable to both gas chromatography (GC) and liquid chromatography (LC) while also improving the physical stability of the resulting device, in addition to eliminating the need for highly toxic reagents associated with the preparation of fully fluorinated based coatings previously reported in the literature. Additional incorporation of other polymers to increase coating porosity as well as the adhesion of PVDF on metal surfaces is also described.</p> | Varoon Singh; Chiranjit Ghosh; Avneet Kaur; Janusz Pawliszyn | Coating Materials; Thin Films; Analytical Apparatus | CC BY NC ND 4.0 | CHEMRXIV | 2020-09-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74feb842e65295fdb3910/original/polyvinylidene-difluoride-a-universal-binder-for-preparation-of-solid-phase-microextraction-devices.pdf |
6449a1efe4bbbe4bbf4dc26d | 10.26434/chemrxiv-2023-t4swt-v2 | Unraveling the Phase Behavior, Mechanical Stability, and Protein Reconstitution Properties of Polymer-Lipid Hybrid Vesicles | Hybrid vesicles consisting of natural phospholipids and synthetic amphiphilic copoly- mers have shown remarkable material properties and potential for biotechnology, com- bining the robustness of polymers with the biocompatibility of phospholipid mem- branes. To predict and optimize the mixing behavior of lipids and copolymers, as well as understand the interaction between the hybrid membrane and macromolecules like membrane proteins, a comprehensive understanding at the molecular level is essen- tial. This can be achieved by a combination of molecular dynamics simulations and experiments. Here, simulations of POPC and PBd22-b-PEO14 hybrid membranes are shown, uncovering different copolymer configurations depending on the polymer-to- lipid ratio. High polymer concentrations created thicker membranes with an extended polymer conformation, while high lipid content led to the collapse of the polymer chain. High concentration of polymer further correlated with a decreased area com- pression modulus and altered lateral pressure profiles, hypothesized to result in the experimentally-observed improvement in membrane protein reconstitution and resis- tance towards destabilization by detergents. Finally, simulations of a WALP peptide embedded in the bilayer showed that only membranes with up to 50% polymer con- tent favored a transmembrane configuration. These simulations correlate with previous and new experimental results and provide a deeper understanding of the properties of lipid-copolymer hybrid membranes. | Wagner Muller; Paul Beales; André Muniz; Lars Jeuken | Theoretical and Computational Chemistry; Polymer Science; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-04-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6449a1efe4bbbe4bbf4dc26d/original/unraveling-the-phase-behavior-mechanical-stability-and-protein-reconstitution-properties-of-polymer-lipid-hybrid-vesicles.pdf |
6687aa33c9c6a5c07a59a394 | 10.26434/chemrxiv-2024-hn8ld | Mobile Intrinsic Point Defects for Conductive Neutral
Domain Walls in LiNbO3 | Conductive ferroelectric domain walls (DWs) hold great promise for neuromorphic nanoelectronics as they can contribute to realize multi-level diodes and nanoscale memristors. Point defects accumulating at DWs will change the local electrical transport properties. Hence, local, inter-switchable n- and p-type conductivity at DWs can be achieved through point defect population control. Here,
we study the impact of point defects on the electronic structure at neutral domain walls in LiNbO3 by density functional theory (DFT). Segregation of Li and O vacancies was found to be energetically favourable neutral DWs, implying that charge-compensating electrons or holes can give rise to n- or p-type conductivity. Changes in the electronic band gap and defect transition levels are discussed with respect to local property engineering, opening the pathway for reversible tuning between n- and
p-type conduction at neutral ferroelectric DWs. Specifically, the high Curie temperature of LiNbO3 and the significant calculated mobility of O and Li vacancies suggest that thermal annealing and applied electric fields can be used experimentally to control point defect populations, and thus enable rewritable pn-junctions. | Kristoffer Eggestad; Benjamin A. D. Williamson; Dennis Meier; Sverre M. Selbach | Materials Science; Nanoscience; Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2024-07-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6687aa33c9c6a5c07a59a394/original/mobile-intrinsic-point-defects-for-conductive-neutral-domain-walls-in-li-nb-o3.pdf |
6798c56bfa469535b92af0d3 | 10.26434/chemrxiv-2024-lthtv-v2 | Alloy Reorganization and Dynamics in Group-10-metal-Gallium Nanoparticles under Reactive Atmospheres: Impact on Local Environment and Reactivity. | Bimetallic nanoparticles are catalysts for reactions as COx hydrogenation or propane dehydrogenation. Recently, gallium has been identified as a promoter which enables dispersion of transition metal sites, raising their activity and selectivity. However, quantitative information on alloying dynamics under reaction conditions are not readily available and a gen-eral computational method to access such information is lacking. Here, an ab initio molecular dynamics workflow with enhanced sampling methods is used to probe the alloying behavior of Ni-, Pd-, and Pt-Ga nanoparticles under operating conditions (T = 600°C) in presence of H2 or CO. The three metals display different alloying behaviors with Ga: Ni forms a core surrounded by gallium, while Pd and Pt form different alloyed structures. Both H2 and CO shift the alloying state to different extents. A set of three descriptors is then proposed to compare and quantify the alloying behavior of these catalyst models: (i) the position αmin of the most stable alloying state; (ii) the curvature ηα of the free energy at αmin, re-ferred to as the alloying hardness; (iii) the skew κα of the free energy at αmin, which relates to its propensity to alloy or segregate. The cost of alloy reorganization, which correlates with alloy hardness, is a major part of the free energy barri-ers of propane dehydrogenation. Seeing as the alloying behavior of a catalyst is a critical parameter that is overlooked in catalyst design, quantitative descriptors are a first step in designing alloys with set catalytic properties. | Quentin Pessemesse; Alexandre Perochon; Christophe Copéret; Marie-Eve L. Perrin; Pierre-Adrien Payard | Theoretical and Computational Chemistry; Catalysis; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2025-02-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6798c56bfa469535b92af0d3/original/alloy-reorganization-and-dynamics-in-group-10-metal-gallium-nanoparticles-under-reactive-atmospheres-impact-on-local-environment-and-reactivity.pdf |
60c7529d9abda26405f8de4f | 10.26434/chemrxiv.12315455.v2 | Mitochondria-Targeted Inhibitors of the Human SIRT3 Lysine Deacetylase | <p>Sirtuin 3 (SIRT3) is the major protein lysine deacetylase in the mitochondria. This hydrolase regulates a wide range of metabolically involved enzymes and has been considered as a potential drug target in certain cancers. Investigation of pharmacological intervention has been challenging due to a lack of potent and selective inhibitors of SIRT3. Here, we developed a strategy for selective inhibition of SIRT3 in cells, over its structurally similar isozymes that localize primarily to nucleus (SIRT1) and cytoplasm (SIRT2). This was achieved by directing the inhibitors straight to the mitochondria through incorporation of sequences inspired by previously described mitochondria-targeting peptides. Our inhibitors exhibited excellent mitochondrial localization in HeLa cells as indicated by fluorophore-conjugated versions and target engagement was demonstrated by a thermal shift assay of SIRT3 using western blotting. The acetylation state of documented SIRT3 target MnSOD was shown to be perturbed in cells with little effect on known targets of SIRT1 and SIRT2, showing that our lead compound exhibits selectivity for SIRT3 in cells. We expect that the developed inhibitor will now enable a more detailed investigation of SIRT3 as a potential drug target and help shed further light on the diverse biology regulated by this enzyme. </p> | Kathrin Sten Troelsen; Michael Bæk,; Alexander Lund Nielsen; Andreas Stahl Madasen; Nima Rajabi; Christian Adam Olsen | Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2020-11-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7529d9abda26405f8de4f/original/mitochondria-targeted-inhibitors-of-the-human-sirt3-lysine-deacetylase.pdf |
66562d3f418a5379b080c1d0 | 10.26434/chemrxiv-2024-jp63v-v2 | Total Synthesis of (–)-Rauvomine B via a Strain-Promoted Intramolecular Cyclopropanation | We describe the first total synthesis of the unusual cyclopropane-containing indole alkaloid (–)-rauvomine B via a strategy centered upon intramolecular cyclopropanation of a tetracyclic N-sulfonyl triazole. Preparation of this precursor evolved through two generations of synthesis, with the ultimately successful route involving a palladium-catalyzed stereospecific allylic amination, a cis-selective Pictet–Spengler reaction, and ring-closing metathesis as important bond-forming reactions. The key cyclopropanation step was found to be highly dependent on the structure and conformational strain of the indoloquinolizidine N-sulfonyl triazole precursor, the origins of which are explored computationally through DFT studies. Overall, our synthesis proceeds in 11 total steps and 2.4% yield from commercial materials. | Jake Aquilina; Ankush Banerjee; Gabriel Morais; Shuming Chen; Myles Smith | Theoretical and Computational Chemistry; Organic Chemistry; Catalysis; Natural Products; Organic Synthesis and Reactions; Computational Chemistry and Modeling | CC BY NC 4.0 | CHEMRXIV | 2024-05-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66562d3f418a5379b080c1d0/original/total-synthesis-of-rauvomine-b-via-a-strain-promoted-intramolecular-cyclopropanation.pdf |
62e7cd1a04c85f08c47fc6ce | 10.26434/chemrxiv-2021-qjzbj-v2 | Modelling amorphous materials via a joint solid-state NMR and X-ray absorption spectroscopy and DFT approach: application to alumina | Understanding electronic structure is a crucial component in the development of many functional materials including semiconductors, transparent-conducting oxides, and batteries, and is necessarily directly dependent on their underlying atomistic structure. The elucidation of atomistic structure is impeded, both experimentally and computationally, by structural disorder, presenting a huge challenge for designing functional amorphous materials. Amorphous materials may be characterised through their local atomic arrangements using, for example, solid-state NMR and X-Ray Absorption Spectroscopy (XAS). By using these two spectroscopy methods to inform the sampling of configurations from ab initio molecular dynamics we devise and validate an amorphous model, choosing amorphous alumina to illustrate the approach due to its wide range of technological uses. Our model predicts two distinct geometric arrangements of AlO5 coordination polyhedra and determines the origin of the pre-edge features in the Al K-edge XAS. We finally construct an average electronic density of states for amorphous alumina, and identify localized states at the conduction band minimum (CBM). We show that the CBM is comprised of Al 3s states and connect this localization and the presence of the pre-edge in the XAS. Deconvoluting this XAS by coordination geometry reveals contributions from both AlO4 and AlO5 geometries at the CBM give rise to the pre-edge, which provides insight into the role of AlO5 in the electronic structure of alumina. This work represents an important advance within the field of solid-state amorphous modelling, providing a method for developing amorphous models through comparison of experimental and computationally derived spectra, which may then be used to determine the electronic structure of amorphous materials. | Angela F Harper; Steffen P Emge; Pieter C M M Magusin; Clare P Grey; Andrew J Morris | Theoretical and Computational Chemistry; Physical Chemistry; Inorganic Chemistry; Computational Chemistry and Modeling; Theory - Computational; Spectroscopy (Physical Chem.) | CC BY 4.0 | CHEMRXIV | 2022-08-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62e7cd1a04c85f08c47fc6ce/original/modelling-amorphous-materials-via-a-joint-solid-state-nmr-and-x-ray-absorption-spectroscopy-and-dft-approach-application-to-alumina.pdf |
60c741a19abda217b5f8beaa | 10.26434/chemrxiv.8068334.v1 | Towards Understanding the Different Influences of Grain Boundaries on Ion Transport in Sulfide and Oxide Solid Electrolytes | Solid electrolytes provide a route to the development of all-solid-state batteries that can potentially surpass the safety and performance of conventional liquid electrolyte-based devices. Sulfide solid electrolytes have received particular attention as a result of their high ionic conductivities. One of the main reasons for such high ionic conductivity is the apparently reduced grain boundary resistance of sulfide solid electrolytes compared to their oxide counterparts, but this is not fully established. Using two model electrolyte systems, Na3PS4 and Na3PO4, we apply a novel microscale simulation approach to analyze ionic transport in polycrystalline materials with various grain volumes. For Na3PO4, high grain boundary resistance is found, with the Na-ion conductivity decreasing with decreasing grain volume. For Na3PS4, the overall influence of grain boundaries is significantly reduced compared to the oxide. Detailed analysis reveals a minimal change in the local structures and Na-ion conduction mechanism between bulk and polycrystalline Na3PS4, whereas the change is far more substantial for Na3PO4, with evidence of over-coordination of Na ions at the grain boundaries. Our microscale approach helps to explain the fundamentally different influences of grain boundaries on ion transport in phosphate and thiophosphate solid electrolytes. | James Dawson; Pieremanuele Canepa; Matthew Clarke; Theodosios Famprikis; Dibyajyoti Ghosh; Saiful Islam | Nanostructured Materials - Nanoscience; Electrochemistry; Solid State Chemistry; Computational Chemistry and Modeling; Energy Storage | CC BY NC ND 4.0 | CHEMRXIV | 2019-05-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c741a19abda217b5f8beaa/original/towards-understanding-the-different-influences-of-grain-boundaries-on-ion-transport-in-sulfide-and-oxide-solid-electrolytes.pdf |
64520f9027fccdb3ea6a7fce | 10.26434/chemrxiv-2023-n0dxz | q-pac: A Python Package for Machine Learned Charge Equilibration Models | Many state-of-the art machine learning (ML) interatomic potentials are based on a local or semi-local (message-passing) representation of chemical environments. They therefore lack a description of long-range electrostatic interactions and non-local charge transfer. In this context, there has been much interest in developing ML-based charge equilibration models, which allow the rigorous calculation of long-range electrostatic interactions and the energetic response of molecules and materials to external fields. The recently reported kQEq method achieves this by predicting local atomic electronegativities using Kernel ML. This paper describes the q-pac Python package, which implements several algorithmic and methodological advances to kQEq and provides an extendable framework for the development of ML charge equilibration models. | Martin Vondrák; Karsten Reuter; Johannes T. Margraf | Theoretical and Computational Chemistry; Machine Learning | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64520f9027fccdb3ea6a7fce/original/q-pac-a-python-package-for-machine-learned-charge-equilibration-models.pdf |
60c74c8abdbb89cf7da397ee | 10.26434/chemrxiv.12496736.v1 | Amino-Functionalization of Vinyl-Substituted Aromatic Diimides by Quantitative and Catalyst-Free Hydroamination | Development of facile and versatile synthetic tools for decorating π-conjugated
molecules has attracted considerable interest because of their potential application in
creating novel π-electron materials. Reported herein are quantitative catalyst-free
hydroamination reactions of a series of aromatic diimide compounds having vinyl
groups at the π-core, which have been confirmed by NMR, UV–vis absorption
spectroscopy, mass analysis, and single crystal X-ray structural analysis. Kinetic studies
revealed that the hydroamination reaction of a vinyl-substituted naphthalenediimide
with an aliphatic amine proceeded rapidly under benign conditions. Similary, the two
vinyl groups attached to aromatic diimides reacted with amines simultaneously,
resulting in the formation of amine bisadducts and macromolecules. | Haruki SANEMATSU; Yoshitaka Matsushita; Masayuki TAKEUCHI; Atsuro TAKAI | Dyes and Chromophores | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74c8abdbb89cf7da397ee/original/amino-functionalization-of-vinyl-substituted-aromatic-diimides-by-quantitative-and-catalyst-free-hydroamination.pdf |
67d02fd081d2151a02fe2575 | 10.26434/chemrxiv-2025-8s16m | Catalyst-free Dynamic Covalent Knoevenagel/Hydrazide Condensa-tion for Polyacylhydrazones and Covalent Adaptable Networks | The rapid advancement of dynamic covalent chemistry (DCvC) has significantly impacted both chemistry and materials science. There is an increasing need for exploring catalyst-free dynamic covalent reactions with large equilibrium con-stant (Keq) ranges to provide new avenues for the tailored design of dynamers. Here, we report a catalyst-free dynamic covalent condensation reaction between Knoevenagel derivatives and hydrazides to generate acylhydrazones. Systematic small-molecule studies validate a significant substituent effect on the Kn reactant, resulting in a wide Keq range covering nearly four orders of magnitude (0.1 ~ 719). The high Keq values (> 500) achieved in polar aprotic solvents enable the catalyst-free synthesis of high-molar-mass (~ 180 kDa) polyacylhydrazones. The retention of by-products during poly-condensation leads to concentration-dependent topology switching between polymeric and macrocyclic acylhydrazones. By leveraging this reaction, we developed a novel covalent adaptable network (CAN) that exhibits remarkable stress re-laxation properties (38 s at 160 °C), facilitating efficient thermal reprocessing while maintaining high mechanical perfor-mance. This condensation reaction enriches the dynamic covalent toolbox and offers a versatile approach for the design and fabrication of dynamers with tailored mechanical and dynamic behavior. | Pengyun Li; Jingwen Zhang; Zhiqiang Wang; Chong Li; Huiping Wu; Mengying Lei; Ge Yan; He Tian; Ruirui Gu; Da-Hui Qu | Polymer Science; Polymerization (Polymers) | CC BY NC ND 4.0 | CHEMRXIV | 2025-03-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67d02fd081d2151a02fe2575/original/catalyst-free-dynamic-covalent-knoevenagel-hydrazide-condensa-tion-for-polyacylhydrazones-and-covalent-adaptable-networks.pdf |
6707b77f51558a15efb0a261 | 10.26434/chemrxiv-2024-swrbm | A Triangular Frustrated Eu(II)–Organic Framework for Sub-Kelvin Magnetic Refrigeration | Attaining very-low temperatures remains technologically challenging and often relies on the scarce resource 3He, unless employing adiabatic demagnetisation refrigeration. Herein, the active coolant typically consists of weakly coupled paramagnetic ions, whose magnetic interaction strengths are comparable in energy to the relevant temperature regime of cooling. Such interactions depend strongly on inter-ion distances, fundamentally hindering the realisation of dense coolants for sub-Kelvin refrigeration. We present a magnetically concentrated triangular coordination network, Eu0.9Ba0.1I2(pyrazine)3, featuring the large s = 7/2 moment of Eu(II). Electron paramagnetic resonance, magnetization, and heat capacity measurements reflect antiferromagnetic correlations between the Eu(II) ions and a dominant easy-plane magnetic anisotropy. The ensuing geometric frustration prevents entropy-annihilating magnetic order down to at least 0.17 K, that is, a remarkably low working temperature for a relatively dense magnetic refrigerant. | Anna Manvell; Maja Dunstan; David Gracia; Jakub Hrubý; Mariusz Kubus; James McPherson; Elias Palacios; Hogni Weihe; Stephen Hill; Jürgen Schnack; Marco Evangelisti; Kasper Steen Pedersen | Physical Chemistry; Inorganic Chemistry; Coordination Chemistry (Inorg.); Physical and Chemical Properties; Materials Chemistry; Crystallography | CC BY NC ND 4.0 | CHEMRXIV | 2024-10-14 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6707b77f51558a15efb0a261/original/a-triangular-frustrated-eu-ii-organic-framework-for-sub-kelvin-magnetic-refrigeration.pdf |
6685cead5101a2ffa84f9936 | 10.26434/chemrxiv-2024-9ks60 | Biocatalytic C–H Oxidation Meets Radical Cross-Coupling: Simplifying Complex Piperidine Synthesis | Medicinal chemists in the modern era are targeting molecules with greater complexity to address increasingly challenging biological targets, a drive to enhance on-target specificity as well as physiochemical properties. As such, structures with greater fraction sp3 (Fsp3) character, reminiscent to those found in nature, are being synthesized. Many decades of synthetic methodology development have democratized access to flat, high sp2 (for example biaryl linkages) which has led to the commercialization of innumerable medicines. Those approaches rely heavily on electrophilic aromatic substitution (such as halogenation) followed by Pd-based cross coupling. In contrast, methods and strategies that allow for similarly modular and rapid construction of three-dimensional saturated molecules are less well developed. Here we exemplify a new approach for the rapid, modular, enantioselective construction of piperidine frameworks (the saturated analog of pyridine) that combines robust, tunable, and scalable biocatalytic methods with the logic of radical cross coupling. Thus, a set of reliable enzymatic systems (analogous to site-selective aromatic functionalization) provides scalable access to enantiopure hydroxyacid- containing piperidine derivatives that can be utilized to dramatically simplify routes to medicinally important molecules and natural products by employing recently developed electrocatalytic couplings (analogous to Pd-based cross couplings in aromatic systems). This study points to a different approach to rapidly access complex architectures that may appeal to both medicinal and process chemists alike. | Jiayan He; Kenta Yokoi; Breanna Wixted; Benxiang Zhang; Yu Kawamata; Hans Renata; phil baran | Organic Chemistry; Organic Synthesis and Reactions | CC BY 4.0 | CHEMRXIV | 2024-07-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6685cead5101a2ffa84f9936/original/biocatalytic-c-h-oxidation-meets-radical-cross-coupling-simplifying-complex-piperidine-synthesis.pdf |
60c73dd4337d6c522be26243 | 10.26434/chemrxiv.6167930.v1 | Gene Set Enrichment Analysis (GSEA) of Upregulated Genes in Cocaine Addiction Reveals miRNAs as Potential Therapeutic Agents | <p>Cocaine
addiction is a global health problem that causes substantial damage to the
health of addicted individuals around the world. Dopamine synthesizing neurons
in the brain play a vital role in the addiction to cocaine. But the underlying
molecular mechanisms that help cocaine exert its addictive effect have not been
very well understood. Bioinformatics can be a useful tool in the attempt to
broaden our understanding in this area. In the present study, Gene Set
Enrichment Analysis (GSEA) was carried out on the upregulated genes from a
dataset of Dopamine synthesizing neurons of post-mortem human brain of cocaine
addicts. As a result of this analysis, 3 miRNAs have been identified as having
significant influence on transcription of the upregulated genes. These 3 miRNAs
hold therapeutic potential for the treatment of cocaine addiction. </p> | Ishtiaque Ahammad | Bioinformatics and Computational Biology | CC BY NC ND 4.0 | CHEMRXIV | 2018-04-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73dd4337d6c522be26243/original/gene-set-enrichment-analysis-gsea-of-upregulated-genes-in-cocaine-addiction-reveals-mi-rn-as-as-potential-therapeutic-agents.pdf |
651f24b845aaa5fdbb5ff5e2 | 10.26434/chemrxiv-2023-bqj91 | Effect of Water On Deep Eutectic Solvents: Structural Properties and Interactions with CO2 | One of the biggest research challenges of the current time is developing technologies for removing CO2 from air. Deep eutectic solvents (DESs), specifically comprised of ionic liquids along with hydrogen bond donors, are promising for direct air capture (DAC) due to their low volatilities, high thermal stabilities, tuneable properties, and high sustainabilities. As water is inevitable in DAC, DESs designed for DAC must be able to function in the presence of water. Addition of water to DESs is believed to have a strong impact on DES properties, including hydrogen bond networks, molecular transport, and interactions with CO2. This study employs classical molecular dynamics (MD) simulations to explore the impact of water addition on the structural and intermolecular properties of DESs composed of 1-ethyl-3-methylimidazolium cations ([EMIM]) and 2-cyanopyrrolide anions ([2CNPyr]) along with three different hydrogen bond donors - ethylene glycol (EG), propylene glycol (PG), and monoethanolamide (MEA). Results show significant structural changes in the DESs due to addition of water, including enhanced interactions between CO2 and [EMIM], [2CNpyr], and MEA. | Sanchari Bhattacharjee; Rachel Getman | Theoretical and Computational Chemistry; Computational Chemistry and Modeling | CC BY NC 4.0 | CHEMRXIV | 2023-10-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/651f24b845aaa5fdbb5ff5e2/original/effect-of-water-on-deep-eutectic-solvents-structural-properties-and-interactions-with-co2.pdf |
66fb91cb12ff75c3a10579c9 | 10.26434/chemrxiv-2024-d1grv | Benchtop 19F NMR Spectroscopy optimized Knorr pyrazole synthesis of Celecoxib and Mavacoxib, 3-(trifluoromethyl) pyrazolyl benzenesulfonamides Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) | Fluorinated organic compounds have demonstrated remarkable utility in medicinal chemistry due to their enhanced metabolic stability and potent therapeutic efficacy. Several examples exist of fluorinated non-steroidal anti-inflammatory drugs (NSAIDs) including diflunisal, flurbiprofen, and trifluoromethylated pyrazoles celecoxib and mavacoxib. These trifluoromethylated pyrazoles, which are most commonly constructed through cyclocondensation of a trifluorinated 1,3-dicarbonyl and an aryl hydrazine, are also found in numerous other drug candidates. Here, we interrogate the effects of solvent and the presence of Brønsted or Lewis acid catalysts on catalyzing this process. We highlight the utility of benchtop 19F NMR spectroscopy in enabling real-time quantification of reaction progress and identification of fluorinated species present in crude reaction mixtures without the need for cost-prohibitive deuterated solvents. Ultimately, we find that the reaction solvent has the greatest impact on rate and product yield, and also found that the relationship between keto-enol equilibrium of the dicarbonyl starting material pyrazole formation rate is highly solvent dependent. More broadly, we describe the optimization of the yield and kinetics of trifluoromethylpyrazole formation in the synthesis of celecoxib and mavacoxib, which is made possible through high-throughput reaction screening on benchtop NMR. | Andrew Chyu; Selina Xi; Joshua Kim; Galen Liu; Indalina Chan; Seoyeon Hong; Allen Ke; Thomas Lavery; Anushree Marimuthu; Arjun Akula; Edward Njoo | Organic Chemistry; Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-10-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66fb91cb12ff75c3a10579c9/original/benchtop-19f-nmr-spectroscopy-optimized-knorr-pyrazole-synthesis-of-celecoxib-and-mavacoxib-3-trifluoromethyl-pyrazolyl-benzenesulfonamides-non-steroidal-anti-inflammatory-drugs-nsai-ds.pdf |
60c74c7b702a9b65f218b6aa | 10.26434/chemrxiv.12493031.v1 | Effect of Composition and Surface Type on Activity of Transition Metal Oxides and Sulfides for CO2 Electrochemical Reduction | Transition metal oxides (TMO) and transition metal sulfides (TMS) are proven to be promising electrocatalysts for CO2RR but there is no clear understanding on catalyst activity or
product selectivity based on trends in binding free energies. Therefore, a broader array of
TMO and TMS are studied as electrocatalysts for CO2RR thus addressing the gap in this
field. This work shows how different types of surface facets with same catalyst composition can fine-tune the binding free energies of intermediate species by modifying the active
binding site. Here, catalyst activity for CO2RR towards formation of 4 different products
is computed and compared for different materials with (100), (110) and (111) crystal facets
and based on this, product selectivity is determined. Optimal catalyst design strategies for
this family of materials are developed using the binding free energies of 4 key intermediate
species COOH*, CO*, HCO* and H*. In this study, among the materials studied, ZnO
zincblende (100) is the material that showed highest catalyst activity towards CO2RR to
CH3OH and CH4 while minimizing HER<br /> | Sahithi Ananthaneni; Rees Rankin | Catalysts; Computational Chemistry and Modeling; Theory - Computational; Electrocatalysis; Heterogeneous Catalysis; Fuels - Energy Science | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74c7b702a9b65f218b6aa/original/effect-of-composition-and-surface-type-on-activity-of-transition-metal-oxides-and-sulfides-for-co2-electrochemical-reduction.pdf |
65fc699a9138d23161f55145 | 10.26434/chemrxiv-2024-rx6gk | Effect of Cations on Monolayer-protected Nanoclusters Aggregation | We studied the effect of metal and molecular cations in the aggregation of atomically precise monolayer-protected nanoclusters (MPCs) in explicit solvent using atomistic molecular dynamics simulations. While divalent cations such as Zn$^{2+}$ and Cd$^{2+}$ promote aggregation by forming ligand-cation-ligand bridges between the MPCs, the molecular cations such as tetraethylammonium and cholinium inhibit their aggregation by getting adsorbed into the MPC's ligand shell and reducing the ligands motion. Here we studied the aggregation of Au$_{25}$(SR)$_{18}$ nanoclusters with two types of ligands - para-amino benzoic Acid and d-penicillamine as prototypical examples. | Vikas Tiwari; Anushna Bhattacharyya; Tarak Karmakar | Physical Chemistry; Physical and Chemical Properties; Self-Assembly; Statistical Mechanics | CC BY NC ND 4.0 | CHEMRXIV | 2024-03-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65fc699a9138d23161f55145/original/effect-of-cations-on-monolayer-protected-nanoclusters-aggregation.pdf |
64f6560579853bbd781bcef6 | 10.26434/chemrxiv-2023-8nrxx | Atlas: A Brain for Self-driving Laboratories | Self-driving laboratories (SDLs) are next-generation research and development platforms for closed-loop, autonomous experimentation that combine ideas from artificial intelligence, robotics, and high-performance computing. A critical component of SDLs is the decision-making algorithm used to prioritize experiments to be performed. This SDL “brain” often relies on optimization strategies that are guided by machine learning models, such as Bayesian optimization. However, the diversity of hardware constraints and scientific questions being tackled by SDLs require the availability of a set of flexible algorithms that have yet to be implemented in a single software tool. Here, we report Atlas, an application-agnostic Python library for Bayesian optimization that is specifically tailored to the needs of SDLs. Atlas provides facile access to state-of-the-art, model-based optimization algorithms—including mixed-parameter, multi-objective, constrained, robust, multi-fidelity, meta-learning, and molecular optimization—as an all-in-one tool that is expected to suit the majority of specialized SDL needs. After a brief description of its core capabilities, we demonstrate Atlas’ utility by optimizing the oxidation potential of metal complexes with an autonomous electrochemical experimentation platform. We expect Atlas to expand the breadth of design and discovery problems in the natural sciences that are immediately addressable with SDLs. | Riley Hickman; Malcolm Sim; Sergio Pablo-García; Ivan Woolhouse; Han Hao; Zeqing Bao; Pauric Bannigan; Christine Allen; Matteo Aldeghi; Alán Aspuru-Guzik | Theoretical and Computational Chemistry; Organic Chemistry; Materials Science; Machine Learning; Artificial Intelligence; Chemoinformatics - Computational Chemistry | CC BY 4.0 | CHEMRXIV | 2023-09-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64f6560579853bbd781bcef6/original/atlas-a-brain-for-self-driving-laboratories.pdf |
60c73d0c0f50db334c3953f4 | 10.26434/chemrxiv.5336401.v1 | Liquid Marble Interaction Gate for Collision-Based Computing | <div>Liquid marbles are microlitre droplets of liquid, encapsulated by self-organised hydrophobic particles at the liquid/air interface. They offer an efficient approach for manipulating liquid droplets and compartmentalising reactions in droplets. Digital fluidic devices employing liquid marbles might benefit from having embedded computing circuits without electronics and moving mechanical parts (apart from the marbles). We present an experimental implementation of a collision gate with liquid marbles. Mechanics of the gate follows principles of Margolus' soft-sphere collision gate. Boolean values of the inputs are given by the absence (False) or presence (True) of a liquid marble. There are three outputs: two outputs are trajectories of undisturbed marbles (they only report True when just one marble is present at one of the inputs), one output is represented by trajectories of colliding marbles (when two marbles collide they lose their horizontal momentum and fall), this output reports True only when two marbles are present at inputs. Thus the gate implements AND and AND-NOT logical functions. We speculate that by merging trajectories representing AND-NOT output into a single channel one can produce a one-bit half-adder. Potential design of a one-bit full-adder is discussed, and the synthesis of both a pure nickel metal and hybrid nickel/polymer liquid marble is reported.</div> | Thomas C. Draper; Claire Fullarton; Neil Phillips; Ben P. J. De Lacy Costello; Andrew Adamatzky | Core-Shell Materials; Magnetic Materials | CC BY 4.0 | CHEMRXIV | 2017-08-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73d0c0f50db334c3953f4/original/liquid-marble-interaction-gate-for-collision-based-computing.pdf |
60c744ba337d6cb4dae26e80 | 10.26434/chemrxiv.9896873.v1 | A Pressure Swing Approach to Selective CO2 Sequestration Using Functionalised Hypercrosslinked Polymers | <div>
<p>Functionalised hypercrosslinked polymers (HCPs) with
surface areas between 213 – 1124 m<sup>2</sup>/g based on a range of monomers
containing different chemical moieties are evaluated for CO<sub>2</sub> capture
using a pressure swing adsorption (PSA) methodology under humid conditions and
elevated temperatures. The networks demonstrated rapid CO<sub>2</sub> uptake
reaching maximum uptakes in under 60 seconds. The most promising networks demonstrating the
best selectivity and highest uptakes were applied to a pressure swing setup
using simulated flue gas streams. The carbazole, triphenylmethanol and
triphenylamine networks were found to be capable of converting a dilute CO<sub>2</sub>
stream (> 20 %) into a concentrated stream (> 85 %) after only two
pressure swing cycles from 20 bar (adsorption) to 1 bar (desorption). This work
demonstrates the ease by which readily synthesised functional porous materials
can be successfully applied to a pressure swing methodology and used to
separate CO<sub>2</sub> from N<sub>2</sub> from industrially applicable simulated
gas streams under more realistic conditions.</p>
</div>
<br /> | Alex James; Jake Reynolds; Dan Reed; Peter Styring; Robert Dawson | Organic Polymers; Separation Science; Polymers; Solid State Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2019-09-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c744ba337d6cb4dae26e80/original/a-pressure-swing-approach-to-selective-co2-sequestration-using-functionalised-hypercrosslinked-polymers.pdf |
60c752b89abda217bff8de77 | 10.26434/chemrxiv.10058444.v10 | Effects of ABS-g-MAH on morphologies, compatibilities and properties of polycarbonate ternary blends | In this work, ABS-g-MAH was used as the compatibilizer in poly carbonate/acrylonitrile styrene acrylate/poly(methyl methacrylate) blends. The polymer blends were prepared via a two-step method: first, raw PC, ASA, PMMA resins and ABS-g-MAH additives were completely mixed and granulated by extrusion molding, and then the standard PC/ASA/PMMA blends samples were obtained by injection molding. A comprehensive characterizations were performed on the PC/ASA/PMMA blends of their morphologies, mechanical properties and thermal properties. The results showed that the addition of ABS-g-MAH could promote the compatibilities among PC, ASA and PMMA, and ABS-g-MAH would significantly alter the mechanical and thermal properties of blends. In addition, the modified PC/ASA/PMMA was well compatible with natural rubber and cause less cytotoxicity when interacting with cells. | Ruogu Tang; Wenfa Dong; Dingfang Chen | Polymer blends | CC BY NC ND 4.0 | CHEMRXIV | 2020-10-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c752b89abda217bff8de77/original/effects-of-abs-g-mah-on-morphologies-compatibilities-and-properties-of-polycarbonate-ternary-blends.pdf |
6481e3a14f8b1884b704a250 | 10.26434/chemrxiv-2023-l6kt4 | Unveiling the Synthesis Patterns of Nanomaterials: A Text Mining and Meta-Analysis Approach with ZIF-8 as a Case Study | With the continuously growing number of scientific articles on synthesis of nanomaterials, it becomes impossible for researchers to grasp and comprehend the landscape of synthetic protocols available for a particular material. The aim of this study is to explore the feasibility of extracting the collective knowledge on synthesis of a particular material accumulated over the years from the published corpus of articles and organizing it in a systematic manner. Accordingly, we developed methods to perform detailed text mining on a single nanomaterial target for the purposes of methodology optimisation. Taking the common material ZIF-8 as a case study, we analysed 1600 synthesis protocols to identify trends in parameters, such as reagents, concentrations, and reaction time/temperature. We used this information to find the distribution of synthesis parameters and their relationships to one another, identifying the limits of common reaction parameters and revealing subtle details, such as insolubility of metal acetate reagents in alcoholic solvents, or the occurrence of amorphous oxides at low stoichiometric ratios. We then clustered similar synthesis protocols together, using their relative popularity to identify promising regions of the synthesis phase space for optimisation, reducing the need for brute force synthesis optimisation. The techniques developed here are a general tool accelerating the synthesis development of a wide range of nanomaterials by aggregating existing research trends, averting the need for laborious manual comparison of existing synthesis protocols or repetition of previously-developed techniques. | Joseph Manning; Lev Sarkisov | Theoretical and Computational Chemistry; Materials Science; Hybrid Organic-Inorganic Materials; Nanostructured Materials - Materials; Chemoinformatics - Computational Chemistry | CC BY 4.0 | CHEMRXIV | 2023-06-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6481e3a14f8b1884b704a250/original/unveiling-the-synthesis-patterns-of-nanomaterials-a-text-mining-and-meta-analysis-approach-with-zif-8-as-a-case-study.pdf |
60c744fb702a9b443d18a932 | 10.26434/chemrxiv.9933236.v1 | Use of compound specific δ¹³C stable isotope analysis for intact triacylglycerides using high temperature gas chromatography up to 430°C | Preliminary results from compound specific 13C isotope ratio mass spectrometry measurements of intact triacylglycerides in olive oil achieved by coupling high temperature gas chromatography with oven cycling up to 430C with IRMS | Paul Sutton; Mario Tuthorn; Jason Newton | Food | CC BY 4.0 | CHEMRXIV | 2019-10-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c744fb702a9b443d18a932/original/use-of-compound-specific-13c-stable-isotope-analysis-for-intact-triacylglycerides-using-high-temperature-gas-chromatography-up-to-430-c.pdf |
6555d7042c3c11ed717fd2b0 | 10.26434/chemrxiv-2023-jmslr | Charge Transfer Mechanism in Guanine-based Self-Assembled Monolayers on a Gold Surface | In this work, we have theoretically determined the one-electron oxidation potentials and charge transfer mechanisms in complex systems based on a self-assembled monolayer of guanine molecules adsorbed on a gold surface through different organic linkers. Simulations were carried out in the framework of the Marcus theory and in combination with an additive scheme previously developed. The conformational sampling, description of the environment and effects caused by the linker have been considered. We unravel the phenomena of electric current transport by evaluating the different stages in which charge transfer could occur. The results revealed that the positive charge migrates from the organic layer to the gold surface through a single ligand and driven with the help of the electrostatic interactions of the surrounding molecules. The established computational protocol sheds light on the mechanism behind charge transport in electrochemical DNA-based biosensor nanodevices. | Jesús Lucia-Tamudo; Juan Jose Nogueira; Sergio Díaz-Tendero | Theoretical and Computational Chemistry; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2023-11-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6555d7042c3c11ed717fd2b0/original/charge-transfer-mechanism-in-guanine-based-self-assembled-monolayers-on-a-gold-surface.pdf |
677304966dde43c908d21e87 | 10.26434/chemrxiv-2024-t6pcq | Energy-Activated and Diversifiable Aryne Precursors from Carboxylic Acids | Densely substituted arene rings are ubiquitous in pharmaceuticals and agrochemicals which support human health and wellbeing. Arynes–a triple bond in a benzene ring–are an intriguing solution to the problem of generating decorated arenes. State-of-the-art aryne precursors are plagued by two issues: 1) the additives required for activation are incompatible with many desirable functional groups intrinsic to the aryne itself as well as the coupling partners which limits the scope, and 2) derivatization of the precursors requires lengthy linear sequences often using harsh conditions rendering them impractical for discovery chemists. Here, we show the design of an aryne precursor made in a single step from a commercially available carboxylic acid and then derivatized in a single SNAr step. Unprecedented aryne activation proceeds using blue light or mild heat, avoiding the use of additives. The model system for this precursor incorporates an ortho-amino group in the final stage because anilines are found in 40% of medicinal chemistry patents and are highly underrepresented in aryne methodology. These precursors have the potential to supersede existing precursors and enable broad access to this desirable synthon. | Chris Seong; Sallu Kargbo; Chia-Ling Yu; Daniel Gibney; Jan-Niklas Boyn; Courtney Roberts | Organic Chemistry; Photochemistry (Org.) | CC BY NC ND 4.0 | CHEMRXIV | 2024-12-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/677304966dde43c908d21e87/original/energy-activated-and-diversifiable-aryne-precursors-from-carboxylic-acids.pdf |
619bf7fae0ea847d81a37104 | 10.26434/chemrxiv-2021-l0lrr | Should India move towards vehicle electrification? Assessing life-cycle greenhouse gas and criteria air pollutant emissions of alternative and conventional fuel vehicles in India. | India is the third largest contributor of greenhouse gases and its transportation emissions account for nearly one-fifth of all greenhouse gas (GHG) emissions. Furthermore, the transportation sector accounts a significant part of other air pollutant emissions that have damaging consequences to human health. Up until now, it was unclear what the greenhouse gas and air pollutant emissions consequences of electrifying vehicles in India would be, as replacing traditional vehicles with electrified ones reduces tailpipe emissions, but it will increase the emissions from the power sector when vehicles are charging. We mitigate that gap in the literature by performing a state specific life-cycle assessment of GHGs and criteria air pollutant emissions for representative passenger vehicles (four-wheelers, three-wheelers, two-wheelers and buses) driven in Indian states/union territories. We consider several vehicle technologies (internal combustion engine (ICE) vehicles, battery electric vehicles (BEVs), hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs)). We find that in most states, four-wheeler BEVs have higher greenhouse gases and criteria air pollutant emissions than other conventional or alternative vehicles and thus electrification of that vehicle class would not lead to emissions reductions. In contrast, in most states, electrified buses and three-wheelers are the best strategy to reduce greenhouse gases, but these are also the worst solution in terms of criteria air pollutant emissions. Electrified two-wheelers have lower criteria air pollutant emissions than gasoline only in five states. The striking conclusion is that unless the Indian grid becomes less polluting, the case for widespread electrification of vehicles for sustainability purposes is simply not there. Moving towards a sustainable, low carbon and low pollution electricity grid is a requirement to make a widespread transportation electrification case for India. | Tapas Peshin; Shayak Sengupta; Inês Azevedo | Energy; Earth, Space, and Environmental Chemistry; Environmental Science | CC BY NC ND 4.0 | CHEMRXIV | 2021-11-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/619bf7fae0ea847d81a37104/original/should-india-move-towards-vehicle-electrification-assessing-life-cycle-greenhouse-gas-and-criteria-air-pollutant-emissions-of-alternative-and-conventional-fuel-vehicles-in-india.pdf |
626a97f2bdc9c2d817e5f698 | 10.26434/chemrxiv-2022-sl1mp | Improving education in electrochemistry via a modeling approach and focusing on green chemistry applications | Chemistry is understood and practiced by research chemists by models and visualization. Electrochemistry is no exception. This study shows how a modeling approach focusing on green chemistry applications holds great potential in improving electrochemistry education. Green electrosynthesis, for instance, is ideally suited to understand electrochemical phenomena and to foster the student’s interest and learning in this cross-disciplinary field of chemical knowledge, reinforcing also laboratory education. | Rosaria Ciriminna; Mina Ghahremani; Fahimeh Varmaghani; Babak Karimi; Mario Pagliaro | Chemical Education; Chemical Education - General | CC BY NC ND 4.0 | CHEMRXIV | 2022-05-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/626a97f2bdc9c2d817e5f698/original/improving-education-in-electrochemistry-via-a-modeling-approach-and-focusing-on-green-chemistry-applications.pdf |
60c747e99abda23387f8c9dc | 10.26434/chemrxiv.11816841.v1 | Mass Spectral Similarity Mapping Applied to Fentanyl Analogs | <b>: </b>This manuscript outlines a straight-forward procedure
for generating a <i>map</i> of similarity between spectra of a set. When
applied to a reference set of spectra for Type I fentanyl analogs (molecules differing
from fentanyl by a single modification), the map illuminates clustering that is
applicable to automated structure assignment of unidentified molecules. An
open-source software implementation that generates mass spectral similarity
mappings of unknowns against a library of Type I fentanyl analog spectra is
available at <a href="http://github.com/asm3-nist/FentanylClassifier">http://github.com/asm3-nist/FentanylClassifier</a>. | Arun Moorthy; Anthony J. Kearsley; W. Gary Mallard; William E. Wallace | Mass Spectrometry | CC BY NC ND 4.0 | CHEMRXIV | 2020-02-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c747e99abda23387f8c9dc/original/mass-spectral-similarity-mapping-applied-to-fentanyl-analogs.pdf |
665db26191aefa6ce1afbb77 | 10.26434/chemrxiv-2024-64vxj | Overcoming the Pitfalls of Computing Reaction Selectivity from Ensembles of Transition States | The prediction of reaction selectivity is a challenging task for computational chemistry, not only because many molecules adopt multiple conformations, but also due to the exponential relationship between effective activation energies and rate constants. To account for molecular flexibility, an increasing number of methods exist that generate conformational ensembles of transition state (TS) structures. Typically, these TS ensembles are Boltzmann weighted and used to compute selectivity assuming Curtin-Hammett conditions. This strategy, however, can lead to erroneous predictions if appropriate filtering of the conformer ensembles is not conducted. Here, we demonstrate how any possible selectivity can be obtained by processing the same sets of TS ensembles for a model reaction. To address the burdensome filtering task in a consistent and automated way, we introduce marc, a tool for the modular analysis of representative conformers that aids in avoiding human errors while minimizing the number of reoptimization computations needed to obtain correct reaction selectivity. | Ruben Laplaza; Matthew D. Wodrich; Clemence Corminboeuf | Theoretical and Computational Chemistry; Physical Chemistry; Organic Chemistry; Physical Organic Chemistry; Computational Chemistry and Modeling; Chemical Kinetics | CC BY NC ND 4.0 | CHEMRXIV | 2024-06-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/665db26191aefa6ce1afbb77/original/overcoming-the-pitfalls-of-computing-reaction-selectivity-from-ensembles-of-transition-states.pdf |
669c5f16c9c6a5c07a037a7a | 10.26434/chemrxiv-2024-pnhwf | Greener Conditions for Asymmetric Coupling of Terminal Alkynes | Asymmetric 1,3-diynes are a common structure motif but remain challenging to prepare from terminal alkynes using Glaser-Hay reactions. Alternative approaches rely on halogenated alkynes, expensive catalysts, or large excess of one reagent to overcome these challenges. We report greener options to prepare asymmetric diynes using a Glaser-Hay type reaction with mixed copper catalysts. Oxygen is employed as a sustainable oxidant to avoid the need for stoichiometric copper. We also show halogenated and toxic solvents can be completely replaced with the sustainable solvent ethyl acetate. The choice of base plays an important role in the reaction as it serves to both deprotonate alkynes and as a ligand for copper. | Crystal Mendoza; Larkin Anderson; Blakely W. Tresca | Organic Chemistry; Catalysis; Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2024-08-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/669c5f16c9c6a5c07a037a7a/original/greener-conditions-for-asymmetric-coupling-of-terminal-alkynes.pdf |
60c752b4567dfee241ec5cfb | 10.26434/chemrxiv.13338320.v1 | Development of Lock-in Based Overtone Modulated MARY Spectroscopy for Detection of Weak Magnetic Field Effects | Modulated magnetically altered reaction yield (ModMARY) spectroscopy is a derivative variant of fluorescence detected magnetic field effect measurement, where the applied magnetic field has both a constant and a modulated component. As in many derivative spectroscopy techniques, the signal to noise ratio scales with the magnitude of the modulation. High modulation amplitudes, however, distort the signal and can obscure small features of the measured spectrum. In order to detect weak magnetic field effects (including the low field effect) a balance of the two has to be found. In this work we look in depth at the origin of the distortion of the MARY signal by field modulation. We then present an overtone detection scheme, as well as a data analysis method which allows for correct fitting of both harmonic and overtone signals of the modulation broadened MARY data. This allows us to robustly reconstruct the underlying MARY curve at different modulation depths. To illustrate the usefulness of the technique, we show measurements and analysis of a well known magnetosensitive system of pyrene / 1,3-dicyanobenzene (Py/DCB). The measurements of first (h1) and second (h2) harmonic spectra are performed at different modulation depths for both natural isotopic abundance, and perdeuterated pyrene samples.<br /> | Marcin Konowalczyk; Olivia Foster Vander Elst; Jonathan Storey | Computational Chemistry and Modeling; Photochemistry (Physical Chem.); Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2020-12-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c752b4567dfee241ec5cfb/original/development-of-lock-in-based-overtone-modulated-mary-spectroscopy-for-detection-of-weak-magnetic-field-effects.pdf |
659b244b9138d2316168f439 | 10.26434/chemrxiv-2024-5p7lv | 1-Cyano-1,2-benziodoxol-3(1H)-one | This comprehensive review discusses the properties, synthesis, and applications of 1-cyano-1,2-benziodoxol-3(1H)-one, a versatile cyanating agent. Various preparative methods are detailed, highlighting its synthesis through different reactions. The review emphasizes its stability and safe handling, making it a preferred choice over other cyanating agents due to its lower toxicity and ease of use. It plays a crucial role in electrophilic cyanation reactions, contributing to the synthesis of diverse organic molecules, including biologically active compounds and pharmaceuticals. The article also explores its application in metal-free, photoredox, and electrochemical methods, underscoring its broad utility in synthetic chemistry. The versatility of 1-cyano-1,2-benziodoxol-3(1H)-one is further demonstrated in its application in the synthesis of metal complexes and its potential in lignin degradation and heterocycle formation. The review concludes by comparing it with other hypervalent iodine reagents, highlighting its superior performance in various cyanation reactions. | Olexandr Pashenko; Serhiy Ryabukhin; Dmytro Volochnyuk | Organic Chemistry; Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2024-01-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/659b244b9138d2316168f439/original/1-cyano-1-2-benziodoxol-3-1h-one.pdf |
655dc2b0cf8b3c3cd7d58c3b | 10.26434/chemrxiv-2023-4hlgd | Application of the RDF framework to integrate heterogenous experimental data of a large chemo- and biodiverse collection from a research collaborative project | Plants have a complex chemo-diversity and represent a reservoir of potential new therapeutic agents. Within a Swiss research project, six scientific research groups from different disciplines are collaborating to investigate a collection of more than 17’000 unique dried plant extracts. It aims to find new bioactive molecules and their modes of action, with for example anti-infective or pro-metabolic activities.
One of the main challenges of this enterprise is the management, integration and sharing of the highly heterogeneous data that are produced by the different research groups. Among these we find (i) massive high-resolution mass spectrometry data, (ii) the numerical results of innovative chemo-informatics methods, (iii) bioassay results from experimental models of tuberculosis and obesity, and (iv) organic synthetic chemistry. Additionally, requirements for data management plan and open-source science with the FAIR principles must be met.
We have established an agile pipeline to capture and structure this heterogeneous data into an RDF graph. The data content's gradual expansion and evolution throughout the project presented considerable challenges, particularly in terms of data modeling. Additionally, despite many collaborators not being RDF experts, most were technically adept at producing RDF triples relevant to their contributions.
We have deployed multiple instances of a triplestore and developed an in-house custom tool (i.e. KGSteward) to synchronize their content, based on a configuration file, which is centrally managed and version-controlled using Git. This strategy gave us the flexibility required to address global project challenges in common data management effectively.
| Frédéric Burdet; Pierre-Marie Allard; Louis-Felix Nothias; Olivier Kirchhoffer; Arnaud Gaudry; Sebastien Moretti; Robin Engler; Luis-Manuel Quiros-Guerrero; Emerson Ferreira Queiroz ; Jahn Nitschke; Nabil Hanna; Chunyan Wu; Antonio Grondin; Bruno David; Thierry Soldati; Christian Wolfrum; Erick Carreira; Jean-Luc Wolfender; Marco Pagni; Florence Mehl | Biological and Medicinal Chemistry | CC BY 4.0 | CHEMRXIV | 2023-11-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/655dc2b0cf8b3c3cd7d58c3b/original/application-of-the-rdf-framework-to-integrate-heterogenous-experimental-data-of-a-large-chemo-and-biodiverse-collection-from-a-research-collaborative-project.pdf |
63efa9309da0bc6b3316827b | 10.26434/chemrxiv-2023-fmf8r-v2 | Strategies on Designing Thiamine Analogues for Inhibition of Thiamine Diphosphate (ThDP)-dependent Enzymes: Systematic Investigation through Scaffold Switching and C2-Functionalisation | Thiamine diphosphate (ThDP), the bioactive form of vitamin B1, is an essential coenzyme needed for processes of cellular metabolism in all organisms. ThDP-dependent enzymes all require ThDP as a coenzyme for catalytic activity, although individual enzymes vary significantly in substrate preferences and biochemical reactions. A popular way to study the role of these enzymes through chemical inhibition is to use thiamine/ThDP analogues, which typically feature a neutral aromatic ring in place of the positive thiazolium ring of ThDP. While ThDP analogues have aided work in understanding the structural and mechanistic aspects of the enzyme family, at least two key questions regarding the ligand design strategy remain unresolved: 1) among the reported aromatic rings, which is the best? and 2) how can we achieve selectivity towards a given ThDP-dependent enzyme? In this work, we synthesise derivatives of these analogues covering all central aromatic rings used in the past decade and make a head-to-head comparison of all the compounds as inhibitors of several ThDP-dependent enzymes. Thus, we establish the relationship between the nature of the central ring and the inhibitory profile of these ThDP-competitive enzyme inhibitors. We also demonstrate that introducing a C2-substituent onto the central ring to explore the unique substrate-binding pocket can improve selectivity. | Alex H. Y. Chan; Terence C. S. Ho; Rimsha Irfan; Rawia A. A. Hamid; Emma S. Rudge; Amjid Iqbal; Alex Turner; Anna K. H. Hirsch; Finian James Leeper | Biological and Medicinal Chemistry; Chemical Biology | CC BY NC 4.0 | CHEMRXIV | 2023-02-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63efa9309da0bc6b3316827b/original/strategies-on-designing-thiamine-analogues-for-inhibition-of-thiamine-diphosphate-th-dp-dependent-enzymes-systematic-investigation-through-scaffold-switching-and-c2-functionalisation.pdf |
60c746b3ee301c0a85c79574 | 10.26434/chemrxiv.9757862.v2 | Computational Discovery of Molecular C60 Encapsulants with an Evolutionary Algorithm | <p>A function-led computational discovery using an evolutionary algorithm was used to find potential fullerene (C60) encapsulants within the chemical space of porous organic cages. This makes use of a tailored fitness function that includes consideration of the interaction energy between the cage and the C60 molecule, the shape persistence of the cage, and the symmetry of the assemblies. We find that the promising host cages for C60 evolve over the simulations towards systems that share features such as the correct cavity size to host C60, planar tri-topic aldehyde building blocks with a small number of rotational bonds, di-topic amine linkers with functionality on adjacent carbon atoms, high structural symmetry, and strong complex binding affinity towards C60. The proposed cages are chemically feasible and similar to cages already present in the literature, helping to increase the likelihood of the future synthetic realisation of these predictions. The presented approach is highly generalisable and can be tailored to target a wide range of properties in molecular encapsulants or other molecular material systems.</p> | Marcin Miklitz; Lukas Turcani; Rebecca L. Greenaway; Kim Jelfs | Supramolecular Chemistry (Org.); Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2019-12-13 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c746b3ee301c0a85c79574/original/computational-discovery-of-molecular-c60-encapsulants-with-an-evolutionary-algorithm.pdf |
633280f10847002e2e8ad2ce | 10.26434/chemrxiv-2022-mgbnq | Direct observation of a new aluminum Lewis acid site in a zeolite | We report the formation of a new Lewis acid Al site in H-FAU zeolite upon 650 ⁰C thermal treatment, unknown for any zeolite. Spectroscopy and DFT calculations reveal this site is a naked Al+3 ion which is charge balanced by a triplet of adjacent framework oxygens with net charge of -1 for each Si-O-Al moiety. This is the first reported observation of a +3 cation stabilized in a zeolite and the first confirmation of existence of aluminum triplets (as opposed to Al pairs) in that can stabilize such cations in siliceous zeolites. This site forms a thermally stable carbonyl O3Al-CO complex with the highest known frequency at 2252 cm-1 for a carbonyl complex on any solid material. These findings open new horizons in zeolite chemistry and expand our understanding of polyvalent metals’ interactions with zeolites. | Konstantin Khivantsev; Stoyan P. Gramatikov; Nicholas R. Jaegers; Miroslaw A. Derewinski; Georgi N. Vayssilov; Janos Szanyi; Hristiyan A. Aleksandrov | Physical Chemistry; Catalysis; Surface; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-09-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/633280f10847002e2e8ad2ce/original/direct-observation-of-a-new-aluminum-lewis-acid-site-in-a-zeolite.pdf |
60c7432f702a9b596118a573 | 10.26434/chemrxiv.8846108.v2 | Simple and Efficient Truncation of Virtual Spaces in Embedded Wave Functions via Concentric Localization | <p>We present a strategy to
generate “concentrically local orbitals” for the purpose of decreasing the
computational cost of wave function-in-density functional theory (WF-in-DFT)
embedding. The concentric localization is performed for the virtual orbitals by
first projecting the virtual space onto atomic orbitals centered on the
embedded atoms. Using a one-particle operator, these projected orbitals are
then used as starting point to iteratively span the virtual space, recursively
creating virtual orbital “shells” with consecutively decreasing correlation
energy recovery at each iteration. This process can be repeated to convergence,
allowing for tunable accuracy. Assessment of the proposed scheme is performed
by application to the potential energy diagram of the Menshutkin reaction of
chloromethane and ammonia inside a segment of a carbon nanotube and the
torsional potential of a simplified version of the retinal chromophore.</p> | Daniel Claudino; Nicholas Mayhall | Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2019-07-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7432f702a9b596118a573/original/simple-and-efficient-truncation-of-virtual-spaces-in-embedded-wave-functions-via-concentric-localization.pdf |
678733acfa469535b9113075 | 10.26434/chemrxiv-2025-j3lq0 | Radical Sorting as a General Framework for Deaminative C(sp3)–C(sp2) Cross-Coupling | Radical-based transition-metal-catalyzed cross-couplings are invaluable tools in synthetic medicinal chemistry. Although carboxylic acids are now routinely used as radical precursors, an equally abundant class of building blocks—aliphatic primary amines—are not typically considered a starting point for radical coupling. We present a general method for deaminative cross-coupling relying on a dual-catalytic system that generates geminate pairs of non-identical alkyl radicals via photosensitization of unsymmetrical 1,2-dialkyldiazenes, then selectively engages the desired radical species in C(sp3)–C(sp2) bond formation. This Ni-mediated ‘radical sorting’ of geminate radical pairs is key in obtaining high yields and avoiding sideproducts. 1,2-dialkyldiazenes are prepared from diverse primary amines, including peptides and pharmaceutical intermediates, using a Sulfur(VI) Fluoride Exchange click linchpin. Mechanistic insights from this work open unique avenues for radical-based synthetic methodologies. | Deepta Chattapadhyay; En-Chih Liu; Mark Jeffrey Diaz; Arunava Maity; Benjamin A. Bratten; Quentin Michaudel | Organic Chemistry; Catalysis; Organometallic Chemistry; Organic Synthesis and Reactions; Homogeneous Catalysis; Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/678733acfa469535b9113075/original/radical-sorting-as-a-general-framework-for-deaminative-c-sp3-c-sp2-cross-coupling.pdf |
63ea1d1e1d2d1840636acb42 | 10.26434/chemrxiv-2023-cgtdn | Three cycles in the dioxomolybdenum-catalyzed reduction
of nitrobenzenes to anilines with pinacol. A computational study towards the valorization of biomass subproducts. | In this work, we use density functional theory to unravel the mechanism of the nitrobenzene to aniline reduction, catalyzed by dioxomolybdenum (VI) dichloride. The use of pinacol as an oxoaccepting reagent and the production of only acetone and water as byproducts, signals a novel and environmentally friendly way to add value to the oxygen-rich biomass-derived polyols. The reaction proceeds through three consecutive cycles, each one responsible for one of the three reductive steps needed to yield nitroaniline from nitrobenzene, with nitrosobenzene and benzylnitrene as intermediates. Each cycle regenerates the Mo(VI) catalyst and releases two acetone molecules. The mechanism involves singlet/triplet state crossings, a feature that has been found to be key in related polyoxomolibdate catalyzed processes. The role of the Mo-coordinated water, product of the reduction of pinacol, as the provider of the mysterious protons needed to reduce the nitro group, was revealed. The disclosure of this challenging mechanism and its rate limiting step can contribute to the design of more effective
Mo(VI) catalysts. | Sofia Kiriakidi; Carlos Silva López; Olalla Nieto Faza | Theoretical and Computational Chemistry; Inorganic Chemistry; Catalysis; Kinetics and Mechanism - Inorganic Reactions; Theory - Computational; Redox Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2023-02-14 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63ea1d1e1d2d1840636acb42/original/three-cycles-in-the-dioxomolybdenum-catalyzed-reduction-of-nitrobenzenes-to-anilines-with-pinacol-a-computational-study-towards-the-valorization-of-biomass-subproducts.pdf |
67c8a34e81d2151a02356862 | 10.26434/chemrxiv-2024-5058z-v3 | Thiophosphate Bioisosteres of Inositol Hexakisphosphate Enhances Binding Affinity and Residence Time to Bacterial Virulence Factors. | Inositol phosphates are essential for mammalian cell signalling with critical roles in cellular processes. The fully phosphorylated inositol phosphate, myo-inositol hexakisphosphate (IP6), modulates numerous eukaryotic proteins and bacterial virulence factors. It has been suggested that the high charge density of IP6 causes restructuring of virulence factors in mammalian cells, activating their enzymatic activity. IP6 is challenging to study due to its phytase instability and propensity to precipitate. Here we suggest that the thiophosphate bioisostere, myo-inositol hexakisthiophosphate (IT6), will mitigate these issues, as thiophosphate substitution has been found to be phytase resistant and improve solubility. Assessment of the chemical properties of IT6 has indeed validated these characteristics. In addition, we performed biophysical characterization of IT6 binding to the virulence factors Salmonella enterica serovar Typhimurium AvrA, Vibrio parahaemolyticus VopA, and Clostridioides difficile TcdB. Our data show that the higher charge density of IT6 increased its binding affinity and residence time to the proteins, which improved stabilization of the bound-state. IT6 is a valuable tool for structural biology research and the described biophysical characteristics of thiophosphate substitution is of value in medicinal chemistry. | Rebecca Cummer; Garvit Bhatt; Lauren M. Finn; Bettina G. Keller; Bhushan Nagar; Bastien Castagner | Biological and Medicinal Chemistry; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2025-03-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67c8a34e81d2151a02356862/original/thiophosphate-bioisosteres-of-inositol-hexakisphosphate-enhances-binding-affinity-and-residence-time-to-bacterial-virulence-factors.pdf |
65151859a69febde9ed3d9ef | 10.26434/chemrxiv-2023-8xt9p | Aptamer-based monitoring of drug uptake into cells and vertebrates | Sensing small molecules, including drugs and their metabolites inside cells, is critical for drug discovery and development, diagnostics, and precision medicine. To facilitate sensitive, long-term studies of drug uptake in cultured cells and animals, we developed a genetically-encoded aptamer biosensor platform for non-invasive real-time measurements of drug distribution. We combined the high specificity of aptamer molecular recognition with the easy-to-detect properties of fluorescent proteins. We tested six different aptamer biosensors, showcasing the platform versatility. The biosensors display high sensitivity and specificity for detecting their specific drug target over related analogs. Furthermore, the biosensor responses were dose dependent and could be detected in individual live cells. We designed our platform for easy integration into animal genomes; thus, we incorporated one aptamer biosensor into zebrafish, an important model vertebrate. The biosensor was stably expressed and enabled non-invasive drug biodistribution imaging in whole animals across different timepoints. To our knowledge, this is the first example of an integrated aptamer biosensor encoded by a vertebrate animal. As such, our aptamer encoded biosensors address the need for non-invasive whole animal biosensing ideal for pharmacokinetic-pharmacodynamic analyses that can be expanded to detect diverse molecules of interest. Furthermore, due to the lack of species-specific machinery, our biosensors can be potentially adapted for any model organism of interest. | Eiman A. Osman; Thomas P. Rynes; Lucia Wang; Karen Mruk; Maureen McKeague | Biological and Medicinal Chemistry; Analytical Chemistry; Imaging; Bioengineering and Biotechnology; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2023-09-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65151859a69febde9ed3d9ef/original/aptamer-based-monitoring-of-drug-uptake-into-cells-and-vertebrates.pdf |
67d493aa81d2151a026636c2 | 10.26434/chemrxiv-2025-ql6hv | dTAT1: An Unnatural Nucleoside Exhibiting Low Photocytotoxicity for Genetic Code Expansion | Synthetic biology's central goal is to create new forms and functions of genetic material by increasing the
information a cell can store and retrieve. Wang and co-workers reached a significant milestone by
engineering the dTAT1-dNaM unnatural base pair that is significantly more photo- and thermostable than
dTPT3-dNaM while exhibiting nearly equal high efficiency and fidelity both in vitro and in vivo. Despite
this breakthrough, the photophysical properties and cell viability of dTAT1 upon exposure to ultraviolet
light, essential for cellular DNA integrity, have remained unexplored. This information is crucial to
understanding the chemical and physical properties that set dTAT1 apart from other unnatural nucleosides
in developing live semisynthetic organisms and therapeutic applications. Herein, we demonstrate that
dTAT1 efficiently populates the reactive triplet state under near-visible light excitation. Surprisingly,
however, cell viability assays indicate no significant cytotoxicity of dTAT1 in human epidermoid carcinoma
cells upon 370 ± 9 nm irradiation or under dark conditions. Reactive Oxygen Species (ROS) analysis reveals
that dTAT1 generates singlet oxygen with a relatively low quantum yield of 17% in aqueous phosphate
buffer, while simultaneously generating superoxide, a significantly less toxic ROS. It is concluded that the
2.7-fold shorter triplet decay lifetime of dTAT1 compared to dTPT3, together with the generation of
superoxide, holds the key to its superior reduction in photocytotoxicity. These findings rationalize the
superior photochemical properties of dTAT1 for its use in synthetic biology and therapeutic applications,
ensuring genetic expansion with minimal cellular disruption, and providing design principles to further
optimize the development of unnatural nucleosides for expanding the genetic code. | Chris Acquah; Sourav Seth; Chuang Feng; Steffen Jockusch; Liraz Levi; Nitza Falcón-Cruz; Lingjun Li; Carlos Crespo-Hernández | Physical Chemistry; Biological and Medicinal Chemistry; Bioengineering and Biotechnology; Cell and Molecular Biology; Photochemistry (Physical Chem.); Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2025-03-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67d493aa81d2151a026636c2/original/d-tat1-an-unnatural-nucleoside-exhibiting-low-photocytotoxicity-for-genetic-code-expansion.pdf |
60c74229842e65821bdb1fec | 10.26434/chemrxiv.8222456.v1 | Multiplexed Chemical Control of Signaling Pathways by Orthogonal, Plasma Membrane-Specific SLIPT Systems | Most cell behaviors are the outcome of processing information from multiple signals generated upon cell stimulation. A systematic understanding of cellular systems requires methods that activate multiple signaling molecules or pathways in single cells. However, the construction of tools for such multiplexed signal control is challenging. Here we present orthogonal chemogenetic systems that allow control of multiple signaling pathways in living mammalian cells based on self-localizing ligand-induced protein translocation (SLIPT). Two orthogonal SLIPT systems were constructed to enable chemically inducible, individual translocation of two proteins from the cytoplasm to the inner-leaflet of the plasma membrane in the same cell. The SLIPT systems combined with fluorescent reporters achieved simultaneous multiplexed activation and monitoring of endogenous Ras/ERK and PI3K/Akt pathways in single cells. Thus, orthogonal SLIPT systems provide a powerful platform for multiplexed chemical signal control in single cells, offering new opportunities for dissecting cell signaling networks and synthetic cell manipulation.<br /> | Akinobu Nakamura; Choji Oki; Kenya Kato; Satoko Fujinuma; Gembu Maryu; Keiko Kuwata; Tatsuyuki Yoshii; Michiyuki Matsuda; Kazuhiro Aoki; Shinya Tsukiji | Bioengineering and Biotechnology; Cell and Molecular Biology; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2019-06-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74229842e65821bdb1fec/original/multiplexed-chemical-control-of-signaling-pathways-by-orthogonal-plasma-membrane-specific-slipt-systems.pdf |
60c755949abda2e522f8e3af | 10.26434/chemrxiv.14130107.v1 | Pyrrole Hemithioindigo Antimitotics with Near-Quantitative Bidirectional Photoswitching Photocontrol Cellular Microtubule Dynamics with Single-Cell Precision | <div>
<div>
<div>
<p>Photoswitchably bioactive reagents, known as “photopharmaceuticals”, promise powerful applications in high-precision biological research. Yet most photoswitch scaffolds cannot be quantitatively bidirectionally photoisomerised, so they suffer from residual background
activity that can confound experiments. We rationally designed photopharmaceuticals using the emerging near-quantitative photoswitch pyrrole hemithioindigo (<b>PHTubs</b>), to isomer-specifically inhibit the cytoskeletal protein tubulin. These <b>PHTub</b> reagents allow simultaneous visible-light imaging and photoswitching in live cells, where they could be used for cell-precise photomodulation of microtubule dynamics, and
photocontrol over cell cycle progression and cell death. This is, as far as we know, the first use of a hemithioindigo photopharmaceutical for
high-spatiotemporal-resolution biological control in live cells. This work opens up new horizons for high-precision microtubule research using
<b>PHTubs</b>; and shows the cellular applicability of the near-quantitative photoswitch pyrrole hemithioindigo as a valuable scaffold for photocontrol of a range of other biological targets.
</p>
</div>
</div>
</div> | Alexander Sailer; Joyce Meiring; Constanze Heise; Linda Pettersson; Anna Akhmanova; Julia Thorn-Seshold; Oliver Thorn-Seshold | Organic Compounds and Functional Groups; Photochemistry (Org.); Cell and Molecular Biology; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2021-03-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c755949abda2e522f8e3af/original/pyrrole-hemithioindigo-antimitotics-with-near-quantitative-bidirectional-photoswitching-photocontrol-cellular-microtubule-dynamics-with-single-cell-precision.pdf |
679013956dde43c908a0440d | 10.26434/chemrxiv-2025-k5fc7 | Theoretical Analysis of Bivalent Binding Avidity and Kinetics: Implications for DNA-Encoded Libraries | This study presents a theoretical framework for understanding the binding behavior of bivalent molecules—entities with two linked ligands—to immobilized targets. Bivalent molecules demonstrate increased binding compared to monovalent counterparts due to an avidity effect arising from the enhanced local concentration of the second ligand upon the first ligand's attachment. Our findings indicate that a shorter tether between ligands increases equilibrium bivalent binding, provided the short tether can span adjacent binding sites without strain. However, shorter tethers may also prolong the search for closely spaced targets, delaying equilibrium to an impractical degree. We propose a theoretical model to evaluate the equilibrium and kinetic parameters of bivalent binding, to enable optimal design of bivalent DNA-Encoded Libraries, and to effect highly efficient DNA-Encoded library (DEL) selection processes. | Richard, R. Edward, Eray Watts; Boris Belotserkovskii | Biological and Medicinal Chemistry; Chemical Biology; Drug Discovery and Drug Delivery Systems | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/679013956dde43c908a0440d/original/theoretical-analysis-of-bivalent-binding-avidity-and-kinetics-implications-for-dna-encoded-libraries.pdf |
6576e76dfd283d7904bec035 | 10.26434/chemrxiv-2023-nhdh2-v2 | Attention towards chemistry agnostic and explainable battery lifetime prediction | Predicting and monitoring battery life early and across chemistries is a significant challenge due to the plethora of degradation paths, form factors, and electrochemical testing protocols. Existing models typically translate poorly across different electrode, electrolyte, and additive materials, mostly require a fixed number of cycles, and are limited to a single discharge protocol. Here, an attention based recurrent algorithm for neural analysis (ARCANA) architecture is developed and trained on a unique, ultra-large, proprietary dataset from BASF and a large Li-ion dataset gathered from literature across the globe. ARCANA generalizes well across this diverse set of chemistries, electrolyte formulations, battery designs, and cycling protocols and thus allows for universal extraction of data-driven knowledge of the degradation mechanisms. The model’s adaptability is further demonstrated through fine-tuning on Na-ion batteries. ARCANA advances the frontier of large-scale time series models in analytical chemistry beyond textual data and holds the potential to significantly accelerate discovery-oriented battery research endeavors. | Fuzhan Rahmanian; Robert M. Lee; Dominik Linzner; Kathrin Michel; Leon Merker; Balazs B. Berkes; Leah Nuss; Helge Sören Stein | Physical Chemistry; Materials Science; Energy; Energy Storage | CC BY 4.0 | CHEMRXIV | 2023-12-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6576e76dfd283d7904bec035/original/attention-towards-chemistry-agnostic-and-explainable-battery-lifetime-prediction.pdf |
644a6bca80f4b75b532fd5df | 10.26434/chemrxiv-2023-kbtbm | Synthesis of Stable Neutral Homoaromatic Hydrocarbons | We report the synthesis of a variety of stable neutral homoaromatic molecules. The homoaromatic character is supported by bond length analysis (from crystal structure analysis data) and spectroscopic characteristics in NMR experiments. The influence of substitution on these homoannulenes is investigated and their reactivity with electrophiles is shown. First approaches to further functionalization via cross-coupling are demonstrated. The present work lays out a general approach to stable neutral homoaromatic hydrocarbon molecules. | Trung Tran Ngoc; Jasper van der Welle; Tobias Rüffer; Teichert Johannes | Organic Chemistry; Physical Organic Chemistry; Crystallography – Organic | CC BY NC ND 4.0 | CHEMRXIV | 2023-04-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/644a6bca80f4b75b532fd5df/original/synthesis-of-stable-neutral-homoaromatic-hydrocarbons.pdf |
62de759a7f3aa66c87f6156d | 10.26434/chemrxiv-2022-m90n5 | Stability of magnesium binary and ternary compounds for batteries determined from first principles | Electrochemical stability is a critical performance parameter for the materials used as electrolytes and electrodes in batteries. Using first-principles electronic structure calculations, we have determined the electrochemical stability windows of magnesium binary and ternary spinel compounds. These materials are candidates for protective coating, solid electrolytes and cathodes in Mg-ion batteries, which represent a promising sustainable alternative to Li-ion batteries that still dominate the battery market. Furthermore, we have applied and assessed two different criteria for the chemical stability of compounds. For the spinel materials, we identify the critical role of the ionic radii of the transition metal for the stability of the compounds. In addition, we determine the ion mobility in these materials using a recently developed descriptor. We thus provide guidelines for the choice of promising solid materials for Mg-ion batteries with improved properties. | Mohsen Sotoudeh; Axel Gross | Theoretical and Computational Chemistry; Energy; Computational Chemistry and Modeling; Theory - Computational; Energy Storage | CC BY NC 4.0 | CHEMRXIV | 2022-07-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62de759a7f3aa66c87f6156d/original/stability-of-magnesium-binary-and-ternary-compounds-for-batteries-determined-from-first-principles.pdf |
60c73cc0469df433bef4260b | 10.26434/chemrxiv.14749170.v1 | Substituent Effects on Transient, Carbodiimide-Fueled Geometry Changes in Diphenic Acids | Nucleotide-fueled conformational changes in motor proteins are key to many important cell functions. Inspired by this biological behavior, we report a simple chemical system that exhibits carbodiimide-fueled geometry changes. Bridging via transient anhydride formation leads to a significant reduction of the twist about the biaryl bond of substituted diphenic acids, giving a simple molecular clamp. The kinetics are well-described by a simple mechanism, allowing structure–property effects to be determined. The kinetic parameters can be used to derive important characteristics of the system such as the efficiencies (anhydride yields), maximum anhydride concentrations, and overall lifetimes. Transient diphenic anhydrides tolerate steric hindrance ortho to the biaryl bond but are significantly affected by electronic effects, with electron-deficient substituents giving lower yields, peak conversions, and lifetimes. The results provide useful guidelines for the design of functional systems incorporating diphenic acid units | Isuru Jayalath; Madelyn Gerken; Georgia Mantel; Scott Hartley | Physical Organic Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2021-06-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73cc0469df433bef4260b/original/substituent-effects-on-transient-carbodiimide-fueled-geometry-changes-in-diphenic-acids.pdf |
6555ae9f6e0ec7777f0b30a9 | 10.26434/chemrxiv-2023-0x9fj | A Neutral PCNHCP Co(I)-Me Pincer Complex as a Universal Catalyst for N-Allylic Isomerization | Earth-abundant metal catalyzed double bond transposition offers a sustainable and atom economical route towards the synthesis of internal alkenes. With emphasis specifically on internal olefins and ethers, the isomerization of allylic amines has been particularly underrepresented in the literature. Herein, we report an efficient methodology for the selective isomerization of N-allylic organic compounds including, amines, amides, and imines. The reaction is catalyzed by a neutral PCNHCP Cobalt(I) pincer complex and proceeds via a π-allyl mechanism that includes an unusual 1,2-methyl migration. The isomerization occurs readily at 80 °C and it is compatible with a wide variety of functional groups. The in-situ formed enamines, could additionally be used for a one-pot inverse-electron-demand Diels-Alder reaction to furnish a series of diversely substituted hetero-biaryls, which is further discussed in this report. | Sakthi Raje; Tofayel Sheikh Mohammed; Graham de Ruiter | Catalysis; Organometallic Chemistry; Homogeneous Catalysis; Transition Metal Complexes (Organomet.) | CC BY NC ND 4.0 | CHEMRXIV | 2023-11-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6555ae9f6e0ec7777f0b30a9/original/a-neutral-pcnhcp-co-i-me-pincer-complex-as-a-universal-catalyst-for-n-allylic-isomerization.pdf |
60c751c6337d6c408fe285c2 | 10.26434/chemrxiv.12950270.v2 | Machine Learning Solvation Environments in Conductive Polymers: Application to ProDOT-2Hex with Solvent Swelling | <div>Automated identification and classification of ion solvation sites in diverse chemical systems will improve the understanding and design of polymer electrolytes for battery applications. We introduce a machine learning approach to classify and characterize ion solvation environments based on feature vectors extracted from all-atom simulations. This approach is demonstrated in poly(3,4-propylenedioxythiophene), which is a promising candidate polymer binder for Li-ion batteries. In the dry polymer, four</div><div>distinct Li+ solvation environments are identified close to the backbone of the polymer. Upon swelling of the polymer with propylene carbonate solvent, the nature of Li+ solvation changes dramatically, featuring a rapid diversification</div><div>of solvation environments. This application of machine learning can be generalized to other polymer condensed-phase systems to elucidate the molecular mechanisms underlying ion solvation.</div> | Ioan-Bogdan Magdau; Thomas Miller | Conducting polymers | CC BY NC ND 4.0 | CHEMRXIV | 2020-11-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c751c6337d6c408fe285c2/original/machine-learning-solvation-environments-in-conductive-polymers-application-to-pro-dot-2hex-with-solvent-swelling.pdf |
674daad35a82cea2fab61220 | 10.26434/chemrxiv-2024-vt63v | Synthesis of heterocyclic analogues of Mosher's acid | Mosher’s acid and its derivatives are widely used to determine the enantiomeric excess of chiral compounds through derivatization. Increasing the diversity of the structures of Mosher’s acid analogs will increase the applicability and robustness of the method. We have prepared the first representatives of Mosher’s acid bearing 1,3-azole cores. It was found that C-silylazoles react smoothly with methyl 3,3,3-trifluoropyruvate in presence of F- anion to give the desired Mosher’s acid esters. | Igor Pervak; Andrii Kyrylchuk; Aleksandr Yurchenko; Roman Rudenko; Pavlo Shynkarenko; Yevhenii Novodvorskyi; Evgenij Zarudnitskii | Organic Chemistry; Organic Compounds and Functional Groups; Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2024-12-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/674daad35a82cea2fab61220/original/synthesis-of-heterocyclic-analogues-of-mosher-s-acid.pdf |
60c74c1fbdbb89342aa396fb | 10.26434/chemrxiv.12431966.v1 | Repurposing of FDA-Approved Toremifene to Treat COVID-19 by Blocking the Spike Glycoprotein and NSP14 of SARS-CoV-2 | The global pandemic of Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to the death of more than 350,000 worldwide and over 100,000 in the United States alone. However, there are currently no proven effective pharmacotherapies for COVID-19. Here, we combine homology modeling, molecular docking, molecular dynamics simulation, and binding affinity calculations to determine potential targets for toremifene, a selective estrogen receptor modulator which we have previously identified as a SARS-CoV-2 inhibitor. Our results indicate the possibility of inhibition of the spike glycoprotein by toremifene, responsible for aiding in fusion of the viral membrane with the cell membrane, via a perturbation to the fusion core. An interaction between the dimethylamine end of toremifene and residues Q954 and N955 in heptad repeat 1 (HR1) perturbs the structure, causing a shift from what is normally a long, helical region to short helices connected by unstructured regions. Additionally, we found a strong interaction between toremifene and the methyltransferase non-structural protein (NSP) 14, which could be inhibitory to viral replication via its active site. These results suggest potential structural mechanisms for toremifene by blocking the spike protein and NSP14 of SARS-CoV-2, offering a drug candidate for COVID-19. | William R. Martin; Feixiong Cheng | Drug Discovery and Drug Delivery Systems | CC BY NC 4.0 | CHEMRXIV | 2020-06-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74c1fbdbb89342aa396fb/original/repurposing-of-fda-approved-toremifene-to-treat-covid-19-by-blocking-the-spike-glycoprotein-and-nsp14-of-sars-co-v-2.pdf |
673758147be152b1d02c5e89 | 10.26434/chemrxiv-2024-l9f24-v2 | Metabolic changes in living human lymphoma cells intervening NAD+ metabolism as revealed by NAD(P)H-fluorescence lifetime imaging and para-hydrogen induced polarization NMR. | Proliferating cells have a sustained high demand for regeneration of electron acceptors as NAD(P)+/NAD(P)H is involved in a number of critical redox-reactions within cells. However, their analysis in living cells is still challenging.
We propose that combining label-free NAD(P)H fluorescence lifetime imaging (NAD(P)H-FLIM) and signal-enhanced magnetic resonance (MR) spectroscopy allows new, deeper insights into changes of specific metabolic pathways in living cells.
For proof of principle NAD+-metabolism was perturbed by specific inhibiton of the rate-limiting enzyme of the NAD+ „Salvage pathway“ Nicotinamide phosphoribosyltransferase (NAMPT) by FK866 in RAMOS human lymphoma cells. FK866 treatment leads to NAD(H) reduction followed by reduced RAMOS cell proliferation. The NAD(P)H-FLIM analysis revealed increased general NAD(P)H-dependent metabolic activity indicated by increased ratios of enzyme-bound to total NAD(P)H concentration upon NAMPT-inhibition. More importantly, a marked reduced lactate dehydrogenase (LDH) activity accompanied by NADPH oxidase activity increase is observed. Using signal-enhanced MR spectroscopy a reduced flux of pyruvate to lactate catalyzed by LDH is detectable in real time in living cells. This strongly supports NAD(P)-FLIM analysis and demonstrates that intervening into the NAD+ „Salvage pathway“ can have specific and global consequences for cells.
Our principle study shows how spatially-resolved metabolic imaging techniques, i.e. NAD(P)H-FLIM, are complemented by real-time MR, paving the way towards a comprehensive spatio-temporal understanding of metabolic pathways in living cells. | Lea Marie Jeude; Ruth Leben; Yonghong Ding; Gabriele Stevanato; Stefan Glöggler; Raluca Niesner; Dieter Kube | Biological and Medicinal Chemistry; Biochemistry; Biophysics; Cell and Molecular Biology | CC BY NC 4.0 | CHEMRXIV | 2024-11-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/673758147be152b1d02c5e89/original/metabolic-changes-in-living-human-lymphoma-cells-intervening-nad-metabolism-as-revealed-by-nad-p-h-fluorescence-lifetime-imaging-and-para-hydrogen-induced-polarization-nmr.pdf |
63b2f4f4dadddc69cba32b96 | 10.26434/chemrxiv-2023-z6v6m | Design and Diagnosis of high-performance CO2-to-CO electrolyzer cells | This work reports the design of a highly efficient neutral-pH CO2-to-CO zero-gap electrolyzer incorporating a new family of 2D layered framework-derived mesoporous single atom NiNC catalysts. What sets its performance apart from previous reports is not only the ~100% CO faradaic efficiency at applied current densities of up to 300 mA cm-2 at just above 3 V cell voltage and 40% total energy efficiency, but the uniquely low stoichiometric CO2 excess, stoich, of 1.2 that yields a molar CO concentration of around 70%Vol in the electrolyzer exit stream at 40% single pass CO2 conversion. This CO-rich exit stream and the low cost catalyst makes this electrolyze design ideally suited for cost-effective and energy efficient tandem cell configurations for high C2+ product yields. We also propose and validate a new kinetic diagnostic tool to help resolve mechanisms of undesired CO2 loss. We introduce an experimentally accessible carbon crossover coefficient, CCC, that describes the ratio between non-catalytic acid-base CO2 consumption and catalytically generated alkalinity. It offers an intuitive insight into the nature of the prevalent ionic transport. Combined with the stoich and the faradaic CO efficiency data, the CCC analysis offers practical guidelines toward improved electrolyzer designs. Our CCC-based cell diagnosis can be applied more broadly to all CO2 electrolyzers | Sven Brückner; Quanchen Feng; Wen Ju; Daniela Galliani; Anna Testolin; Malte Klingenhof; Sebastian Ott; Peter Strasser | Materials Science; Catalysis; Energy; Carbon-based Materials; Electrocatalysis; Energy Storage | CC BY 4.0 | CHEMRXIV | 2023-01-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63b2f4f4dadddc69cba32b96/original/design-and-diagnosis-of-high-performance-co2-to-co-electrolyzer-cells.pdf |
61570a1bcc53d94e30b901bd | 10.26434/chemrxiv-2021-7gk5l-v2 | Protein pKa prediction with machine learning | Protein pKa prediction is essential for the investigation of pH-associated relationship between protein structure and function. In this work, we introduce a deep learning based protein pKa predictor DeepKa, which is trained and validated with the pKa values derived from continuous constant pH molecular dynamics (CpHMD) simulations of 279 soluble proteins. Here the CpHMD implemented in the Amber molecular dynamics package has been employed (Huang, Harris, and Shen J. Chem. Inf. Model. 2018, 58, 1372-1383). Notably, to avoid discontinuities at the boundary, grid charges are proposed to represent protein electrostatics. We show that the prediction accuracy by DeepKa is close to that by CpHMD benchmarking simulations, validating DeepKa as an efficient protein pKa predictor. In addition, the training and validation sets created in this study can be applied to the development of machine learning based protein pKa predictors in future. Finally, the grid charge representation is general and applicable to other topics, such as the protein-ligand binding affinity prediction. | Zhitao Cai; Fangfang Luo; Yongxian Wang; Enling Li; Yandong Huang | Theoretical and Computational Chemistry; Theory - Computational; Machine Learning | CC BY NC ND 4.0 | CHEMRXIV | 2021-10-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61570a1bcc53d94e30b901bd/original/protein-p-ka-prediction-with-machine-learning.pdf |
645e93a2a32ceeff2d8a379d | 10.26434/chemrxiv-2023-4ndh3-v2 | Long Range Electron Transport Rates Depend on Wire Dimensions in Cytochrome Nanowires | The ability to redirect electron transport to new reactions in living systems opens possibilities to store energy, generate new products, or probe physiological processes. Recent work by Huang et al. showed that 3D crystals of small tetraheme cytochromes (STC) could transport electrons over nanoscopic to mesoscopic distances by an electron hopping mechanism. Such protein-based structures with multiple localized electron carriers are promising materials for nanowires. A potential barrier to protein nanowire adoption for handling long-range electron transport is that fluctuations at room temperature may distort the nanostructure, hindering efficient electron transport. These fluctuations at the nano- and mesoscopic scales are quantified using classical molecular dynamics simulations for a small fragment of a STC nanowire and measure the effective distance distribution between electron carriers. From distance distributions, we develop a graph network representation for electron transport along nanowires with varying dimensions, and through stochastic methods determine the maximum electron flow that can be driven through these STC wires. Longer nanowires were capable of carrying fewer electrons than shorter nanowires with the same diameter, as long electron transfer distances that occasionally arise reduce the efficiency for electron transport. Thicker nanowires permit more alternative transport pathways, increasing electron transport beyond the increase in cross-section. Thus, this model implies that the design of protein-based nanowires that depend on electron hopping between charge carriers must consider control of the inherent protein flexibility, as more flexible protein-protein interfaces impose a limit on the required minimum diameter to carry currents commensurate with conventional electronics. | Martin Kulke; Dayna Olson; Jingcheng Huang; David Kramer; Josh Vermaas | Theoretical and Computational Chemistry; Nanoscience; Energy; Computational Chemistry and Modeling; Power | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/645e93a2a32ceeff2d8a379d/original/long-range-electron-transport-rates-depend-on-wire-dimensions-in-cytochrome-nanowires.pdf |
62d030cafe12e3dd51a17956 | 10.26434/chemrxiv-2022-41gpv | Effects of Electrochemical Conditioning
on Nickel-based Oxygen Evolution Electrocatalysts
| Electrochemical conditioning via chronopotentiometry (CP) and cyclic voltammetry (CV) is essential for the activation of oxygen evolution reaction (OER) electrocatalysts. While many reports have activated OER electrocatalysts using either CP or CV, the inherent differences between these two electrochemical conditioning methods for the activation of OER electrocatalytic materials have yet to be explored. Here, we investigate the effects of CP and CV electrochemical conditioning on a Ni-based OER precatalyst and substrate in Fe-purified and Fe-unpurified KOH electrolytes by employing (ⅰ) Ni foil, (ⅱ) NiSe precatalyst films with different thicknesses on the fluorine-doped tin oxide glass substrate, and (ⅲ) NiSe precatalyst films on Ni foil substrates. It was found that CV electrochemical conditioning can result in a higher degree of in situ oxidation and Fe incorporation for Ni-based precatalysts and substrates compared to CP electrochemical conditioning. In turn, this brought about different material properties (e.g., in situ oxidized layer thickness, composition, crystallinity, and morphology) and electrochemical characteristics (e.g., active surface area, electron transport limitation, and intrinsic activity) of Ni-based electrocatalysts, thereby not only affecting their OER activity but also complicating the interpretation of the origin of OER activity. This study identifies the distinct effects of CP and CV electrochemical conditioning on Ni-based OER electrocatalysts and provides insight into the choice of the electrochemical conditioning method to better investigate OER electrocatalysts. | Yoon Jun Son; Seonwoo Kim; Vanessa Leung; Kenta Kawashima; Jungchul Noh; Kihoon Kim; Raul A. Marquez; Omar A. Carrasco-Jaim; Lettie A. Smith; Hugo Celio; Delia J. Milliron; Brian Korgel; C. Buddie Mullins | Catalysis; Analytical Chemistry; Energy; Electrochemical Analysis; Electrocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2022-07-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62d030cafe12e3dd51a17956/original/effects-of-electrochemical-conditioning-on-nickel-based-oxygen-evolution-electrocatalysts.pdf |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.