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
⌀ |
|---|---|---|---|---|---|---|---|---|---|
6619a71f91aefa6ce17155c9 | 10.26434/chemrxiv-2024-n14xq | Direct C4- and C2 C–H Amination of Heteroarenes Using I(III) Reagents via a Cross Azine Coupling | Aminated nitrogen heterocycles are valuable motifs across numerous chemical industries, perhaps most notably small mole-cule pharmaceuticals. While numerous strategies exist to install nitrogen atoms onto azaarenes, most require pre-functionalization and methods for direct C–H amination are almost entirely limited to the C2-position. Herein, we report a method for the direct C2 and C4 C–H amination of fused azaarenes via in situ activation with a bispyridine-ligated I(III)-reagent, [(Py)2IPh]2OTf, or Py-HVI. Unlike commonly used N-oxide chemistry, the method requires no pre-oxidation of the azaarene and it provides unprecedented access to C4-amination products. The resulting N-heterocyclic pyridinium salts can be isolated via simple trituration, and the free amine can be liberated under mild Zincke aminolysis, or the amination and cleav-age can be telescoped to a one-pot process. The scope of the method is broad, the conditions are mild and operationally sim-ple, and the aminated products are produced in good to excellent yields. Computational studies provide insights into the mech-anism of activation, which involves an unusual direct nucleophilic functionalization of an I(III)-ligand, as well as a kinetic basis for the observed C2 and C4 amination products. | Bill J Motsch; Amelia H Quach; Jason L Dutton; David J D Wilson; Sarah E Wengryniuk | Organic Chemistry; Organic Compounds and Functional Groups; Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2024-04-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6619a71f91aefa6ce17155c9/original/direct-c4-and-c2-c-h-amination-of-heteroarenes-using-i-iii-reagents-via-a-cross-azine-coupling.pdf |
60c75811469df45a01f45588 | 10.26434/chemrxiv.12386081.v3 | Origin of Enantioselectivity Reversal in Lewis Acid-Catalysed Michael Additions Relying on the Same Chiral Source | Enantiodivergence is an important concept in asymmetric catalysis that enables access to both enantiomers of a product relying on the same chiral source as
reagent. This strategy is particularly appealing as an alternate approach when only one enantiomer of the required chiral ligand is readily accessible but both
enantiomers of the product are desired. Despite the potential significance, general catalytic methods to effectively reverse enantioselectivity by changing an
achiral reaction parameter remain underdeveloped. Herein we report our studies focused on elucidating the origin of metal-controlled enantioselectivity
reversal in Lewis acid-catalysed Michael additions. Rigorous experimental and computational investigations reveal that specific interactions between the
substrate and ligand depending on the choice of metal catalyst are a key factor responsible for the observed enantiodivergence. This holds potential to further
our understanding of and facilitate the design of future enantiodivergent transformations. | Paul S. Riehl; Alistair D. Richardson; Tatsuhiro Sakamoto; Jolene P. Reid; Corinna Schindler | Acid Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2021-04-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75811469df45a01f45588/original/origin-of-enantioselectivity-reversal-in-lewis-acid-catalysed-michael-additions-relying-on-the-same-chiral-source.pdf |
6134a5a827d9065bd77e2a2e | 10.26434/chemrxiv-2021-0cp1z | Simultaneous simulation and optimization of multiple dividing wall columns | In this work we present a new approach that we use to simulate and optimize multiple dividing wall columns at the same time. Instead of considering all model equations as constraints and all process variables as optimization variables in a large and highly nonlinear optimization problem we only incorporate a subset of the model equations as constraints and a subset of the process variables as optimization variables. The remaining process variables are calculated from this subset by a robust and fast calculation procedure. This calculation procedure also ensures that the remaining model equations are satisfied. A comparison with the commercial process simulator Aspen Plus shows that with the new approach multiple dividing wall columns can be optimized more stable and better solutions are found. Moreover the time needed to find an optimal design decreases significantly. | Tobias Seidel; Lena-Marie Ränger; Thomas Grützner; Michael Bortz | Chemical Engineering and Industrial Chemistry | CC BY 4.0 | CHEMRXIV | 2021-09-06 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6134a5a827d9065bd77e2a2e/original/simultaneous-simulation-and-optimization-of-multiple-dividing-wall-columns.pdf |
64d40c5669bfb8925aaa4e32 | 10.26434/chemrxiv-2023-6ml88 | Ultrafast Spectroscopy Reveals Slow Water Dynamics in Biocondensates | Cells achieve high spatiotemporal control over biochemical processes through compartmentalization to membrane-bound, as well as membraneless organelles that assemble by liquid-liquid phase separation. Characterizing the balance of forces within these environments is essential to understanding their stability and function, and water is an integral part of the condensate, playing a nontrivial role in mediating the electrostatic and hydrogen bonding interactions. Here we investigate the picosecond hydrogen-bond dynamics of a model biocondensate consisting of a peptide Poly-L-Arginine and the nucleic acid adenosine monophosphate (AMP) using ultrafast two-dimensional infrared (2D IR) spectroscopy. We investigate three vibrational modes, the arginine side chain C=N stretches, an AMP ring mode, and the amide backbone carbonyl stretches, to provide different perspectives. In general, dynamics slow down considerably between the dilute phase and the condensate phase for each vibrational probe. For example, the arginine side chain C=N modes slows from 0.38 ps to 2.26 ps due to strong electrostatic interactions. Hydrogen bond lifetime computed from all-atom molecular dynamics simulations provide an atomistic interpretation. Simulations predict that a significant fraction of water molecules are highly constrained within the condensate. We attribute this slowdown in dynamics to a highly disordered and extremely crowded water environment. | Keegan Lorenz-Ochoa; Carlos Baiz | Biological and Medicinal Chemistry; Biophysics | CC BY NC 4.0 | CHEMRXIV | 2023-08-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64d40c5669bfb8925aaa4e32/original/ultrafast-spectroscopy-reveals-slow-water-dynamics-in-biocondensates.pdf |
6789029a81d2151a0264327c | 10.26434/chemrxiv-2024-scjdm-v2 | Zinc(II) coordination polymers with 3-(1H-imidazol-1-yl)propanoate linkers | Coordination polymers of zinc(II) with three readily accessible 3-(1H-imidazol-1-yl)propanoate ligands are prepared by combining aqueous solutions of the ligands and zinc(II) salts, resulting in a precipitation of the respective coordination polymers. While sodium 3-(1H-imidazol-1-yl)propanoate and sodium 3-(2-phenyl-1H-imidazol-1-yl)propanoate initially yield amorphous precipitates that can be converted to crystalline materials upon prolonged heating, the use of sodium 3-(2-methyl-1H-imidazol-1-yl)propanoate results in the immediate formation of a crystalline coordination polymer. All three coordination polymers were structurally characterized by single crystal X-ray diffraction. The crystal water in one coordination polymer could be removed without losing the crystallinity of the sample and this process was studied by infrared spectrometry. The interpretation of the corresponding infrared spectra was supported by theoretical calculations. Furthermore, the solubility in water and buffer solutions as well as the potential porosity of the coordination polymers were investigated, revealing their non-porous character for CO2, N2 and CH4. | Katharina Kodolitsch; Ana Torvisco; Tomas Kamencek; Matjaz Mazaj; Egbert Zojer; Christian Slugovc | Inorganic Chemistry; Polymer Science; Coordination polymers | CC BY NC 4.0 | CHEMRXIV | 2025-01-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6789029a81d2151a0264327c/original/zinc-ii-coordination-polymers-with-3-1h-imidazol-1-yl-propanoate-linkers.pdf |
64bf92c8b605c6803b505b0a | 10.26434/chemrxiv-2023-577jj | Differentiation of Truffle Species (Tuber spp.) by 1H NMR Spectroscopy and support vector machine | The price of different truffle types varies according to their culinary value, sometimes by more than a factor of ten. Non-professionals can hardly distinguish the species within the white or black truffles by eye, which makes the possibility of food fraud very easy. Therefore, the identification of different truffle species (Tuber spp.) is an analytical task that could be solved in this study. The polar extract from a total of 80 truffle samples were analyzed by 1H NMR spectroscopy in combination with chemometric methods covering five commercially relevant species. All classification models were validated with nested cross-validation. The two very similar looking and closely related black representatives Tuber melanosporum and Tuber indicum could be classified 100% correctly in direct comparison. The most expensive truffle Tuber magnatum could be distinguished 100% from the other relevant white truffle Tuber borchii. Furthermore, signals for a potential Tuber borchii, and a potential Tuber melanosporum marker for targeted approaches could be detected and the corresponding molecules were identified as betaine and ribonate. A model covering all five truffle species Tuber aestivum, Tuber borchii, Tuber indicum, Tuber magnatum and Tuber melanosporum was able to correctly discriminate between all species. | Thorsten Mix; Jasmin Janneschütz; Markus Fischer; Thomas Hackl | Analytical Chemistry; Agriculture and Food Chemistry; Chemoinformatics; Spectroscopy (Anal. Chem.); Food | CC BY NC ND 4.0 | CHEMRXIV | 2023-08-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64bf92c8b605c6803b505b0a/original/differentiation-of-truffle-species-tuber-spp-by-1h-nmr-spectroscopy-and-support-vector-machine.pdf |
60c751bd4c8919604cad400d | 10.26434/chemrxiv.13142786.v1 | Pentaminomycins F and G, First Non-Ribosomal Peptides Containing 2-Pyridylalanine | Pentaminomycins F-H, a group of three new hydroxyarginine-containing cyclic pentapeptides, were isolated from cultures of a <i>Streptomyces cacaoi</i> subsp. <i>cacaoi</i> strain along with the known pentaminomycins A-E. The structures of the new peptides were determined by a combination of mass spectrometry and NMR and Marfey's analyses. Among them, pentaminomycins F and G were shown to contain in their structures the rare amino acid 3-(2-pyridyl)-alanine. This finding represents the first reported example of non-ribosomal peptides containing this residue. The LDLLD chiral sequence found for the three compounds was in agreement with that reported for previously isolated pentaminomycins and consistent with the epimerization domains present in the putative non-robosomal peptide synthetase (NRPS) biosynthetic gene cluster.<br /> | Daniel Carretero-Molina; Francisco Javier Ortiz-Lopez; Jesús Martín; Ignacio González; Marina Sánchez-Hidalgo; Fernando Román-Hurtado; Caridad Díaz; Mercedes de la Cruz; Olga Genilloud; Fernando Reyes | Natural Products | CC BY NC ND 4.0 | CHEMRXIV | 2020-11-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c751bd4c8919604cad400d/original/pentaminomycins-f-and-g-first-non-ribosomal-peptides-containing-2-pyridylalanine.pdf |
62e14790a8e4dc14f91f2146 | 10.26434/chemrxiv-2022-ntlhr | The Involvement of Triplet State in the Isomerization of Retinaloids | Rhodopsins form a family of photoreceptor proteins which utilize the retinal chromophore for light energy conversion. Upon light absorption the retinal chromophore undergoes a photoisomerization. This reaction involves a non-radiative relaxation through a conical intersection between the singlet excited and ground states. In this work we studied the possible involvement of triplet states in the photoisomerization of retinaloids using extended multistate (XMS) version of CASPT2. To this end, truncated models of three retinaloids were considered: protonated Schiff base, deprotonated Schiff base and the aldehyde form. The optimized geometries of the reactant, the product and the conical intersection were connected by a linear interpolation of internal coordinates to describe the isomerization. The energetic position of the low-lying singlet and triplet states as well as their spin-orbit coupling matrix elements (SOCME) was calculated along the isomerization profile. The SOCME values peaked in vicinity of the conical intersection for all the retinaloids. Furthermore, the magnitude of SOCME is invariant to the number of double bonds in the model. The SOCME for the protonated Schiff base is negligible (1.5 cm-1) which renders the involvement the triplet state as improbable. However, the largest SOCME value of 30 cm-1 was found for the aldehyde form, followed by 15 cm-1 for the deprotonated Schiff base. | Ofer Filiba; Veniamin Borin; Igor Schapiro | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Theory - Computational; Photochemistry (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2022-07-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62e14790a8e4dc14f91f2146/original/the-involvement-of-triplet-state-in-the-isomerization-of-retinaloids.pdf |
60c755b5702a9b83bb18c74c | 10.26434/chemrxiv.11973273.v4 | Artificial Neural Network (FFBP-ANN) Based Grey Relational Analysis for Modeling Dyestuff Solubility in Supercritical CO2 with Ethanol as the Co-Solvent | The research on dye solubility modeling in supercritical carbon dioxide is gaining prominence over the past few decades. A simple and ubiquitous model that is capable of accurately predicting the solubility in supercritical carbon dioxide would be invaluable for industrial and research applications. In this study, we present such a model for predicting dye solubility in supercritical carbon dioxide with ethanol as the co-solvent for a qualitatively diverse sample of eight dyes. A feed forward back propagation - artificial neural network model based on Levenberg-Marquardt algorithm was constructed with seven input parameters for solubility prediction, the network architecture was optimized to be [7-7-1] with mean absolute error, mean square error, root mean square error and Nash-Sutcliffe coefficient to be 0.026, 0.0016, 0.04 and 0.9588 respectively. Further, Pearson-product moment correlation analysis was performed to assess the relative importance of the parameters considered in the ANN model. A total of twelve prevalent semiempirical equations were also studied to analyze their efficiency in correlating to the solubility of the prepared sample. Mendez-Teja model was found to be relatively efficient with root mean square error and mean absolute error to be 0.094 and 0.0088 respectively. Furthermore, Grey relational analysis was performed and the optimum regime of temperature and pressure were identified with dye solubility as the higher the better performance characteristic. Finally, the dye specific crossover ranges were identified by analysis of isotherms and a strategy for class specific selective dye extraction using supercritical CO2 extraction process is proposed. | FNU Srinidhi | Industrial Manufacturing; Thermodynamics (Chem. Eng.) | CC BY NC ND 4.0 | CHEMRXIV | 2021-02-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c755b5702a9b83bb18c74c/original/artificial-neural-network-ffbp-ann-based-grey-relational-analysis-for-modeling-dyestuff-solubility-in-supercritical-co2-with-ethanol-as-the-co-solvent.pdf |
663479ac21291e5d1d4f233f | 10.26434/chemrxiv-2024-fd1g6 | Metal-Organic Frameworks in Surface Enhanced Raman Spectroscopy - based Analysis of Volatile Organic Compounds | Volatile Organic Compounds (VOCs) represent health and environmental hazardous compounds but also play crucial roles in other fields including early disease diagnostics and organoleptic perception of aliments important in food production. Accurate VOCs analysis is essential, and require innovative analytical methods for rapid on-site detection without complex sample preparation. Surface-enhanced Raman spectroscopy (SERS) is a versatile analytical platform ideal for detecting chemical species. It relies on optical probing metallic nanostructures endowing tightly confined electromagnetic fields associated with resonant coupling to surface plasmons, then boosting the efficiency of Raman scattering to sensitivity at even single molecule detection. Nonetheless, SERS faces limitations, especially analytes that do not bond with noble metals. This limitation can be circumvented by interfacing the sensor surface with Metal-Organic Frameworks (MOFs). Known for their chemical and structural versatility, MOFs efficiently pre-concentrate low molecular weight species in their porous structure. This review presents recent developments in MOF-based SERS substrates emphasizing design rules for maximizing analytical performance. An overview of the status of the detection of harmful VOC is discussed in the context of industrial and environmental monitoring. In addition, a survey of VOC analysis for medical diagnosis and emerging applications in aroma and flavor profiling is included. | Juan Allegretto; Jakub Dostalek | Physical Chemistry; Analytical Chemistry; Spectroscopy (Anal. Chem.); Interfaces; Spectroscopy (Physical Chem.); Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2024-05-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/663479ac21291e5d1d4f233f/original/metal-organic-frameworks-in-surface-enhanced-raman-spectroscopy-based-analysis-of-volatile-organic-compounds.pdf |
64617cbffb40f6b3ee99979c | 10.26434/chemrxiv-2023-t2hhx | Vibrational Spectra of Liquid Interfaces with A 100 kHz Sub-1 cm-1 High Resolution Broadband Sum Frequency Generation Vibrational Spectrometer (HR-BB-SFG-VS) | Sub-1 cm-1 high-resolution broadband sum-frequency generation vibrational spectrometer (HR-BB-SFG-VS) using synchronized picosecond and femtosecond lasers at 1 kHz was first reported over a decade ago, and many advantages of the HR-BB-SFG-VS over the conventional BB-SFG-VS have been well-documented. A high-efficient and low-cost version of the HR-BB-SFG-VS is needed for broader adoption of this powerful interface specific spectroscopic technique. Here, we report the realization of such a sub-1 cm-1 HR-BB-SFG-VS with a tunable repetition rate around 100 kHz. Instead of synchronization of an additional expensive 90 picosecond laser for enough power to achieve high spectral resolution SFG measurement, a chirped volume Bragg grating (CVBG) is implemented with the second harmonic band compression (SHBC) unit to generate an intense 90 picosecond laser pulse at 517 nm with a bandwidth of about 0.16 cm-1 from a 150-fs laser pulse at ~1034 nm, with an efficiency of ~26%. The effectiveness of this new SFG system is demonstrated through the SFG spectra obtained with a spectral resolution of 0.6 cm-1 and excellent lineshape from the air/DMSO aqueous solutions interfaces, and the air/water interface, without apparent surface heating effect. This development provides a low-cost and easy-to-implement powerful HR-BB-SFG-VS instrumentation for broad applications in structure and dynamics studies on the illusive molecular surfaces and interfaces. | Jingming Cao; An-An Liu; Shuyi Yang; Xing-xing Peng; Hongfei Wang | Physical Chemistry; Analytical Chemistry; Interfaces; Optics; Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2023-05-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64617cbffb40f6b3ee99979c/original/vibrational-spectra-of-liquid-interfaces-with-a-100-k-hz-sub-1-cm-1-high-resolution-broadband-sum-frequency-generation-vibrational-spectrometer-hr-bb-sfg-vs.pdf |
661df07a418a5379b0ef8906 | 10.26434/chemrxiv-2024-1p4xt | BatGPT-Chem: A Foundation Large Model For Chemical Engineering | LLMs have showcased remarkable capabilities in the realm of AI for Science (Ai4Sci) and the chemistry has greatly benefited from the advancement of AI tools. With a strong capacity for learning sequential data like natural language, LLMs offer immense potential. Notably, common representations in chemistry, such as SMILES, are also in the form of sequences. Hence, we propose leveraging LLMs to comprehensively model both chemical sequences and natural language sequences, aiming to tackle diverse chemical tasks. To fulfill this objective, we introduce BatGPT-Chem, a foundational large-scale model with 15B parameters tailored for chemical engineering. First, we unify diverse tasks in chemistry by modeling them through a combination of natural language and SMILES. Next, leveraging this unified modeling approach, we craft prompt templates and generate instructional tuning data using a substantial volume of chemical data. Subsequently, we train BatGPT-15B on over a hundred million instances of instructional tuning data, empowering it to address tasks such as \textbf{Molecule Description}, \textbf{Molecule Design}, \textbf{Retro-synthesis Prediction}, \textbf{Product Inference}, and \textbf{Yield Prediction}. We release our trial platform at \url{https://www.batgpt.net/dapp/chem}. | Yifei Yang; Runhan Shi; Zuchao Li; Shu Jiang; Yang Yang; Bao-Liang Lu; Hai Zhao | Theoretical and Computational Chemistry; Chemical Engineering and Industrial Chemistry; Machine Learning; Artificial Intelligence | CC BY NC ND 4.0 | CHEMRXIV | 2024-04-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/661df07a418a5379b0ef8906/original/bat-gpt-chem-a-foundation-large-model-for-chemical-engineering.pdf |
64db282f69bfb8925af4df3d | 10.26434/chemrxiv-2023-908pb | Adsorption of Copper by Naturally and Artificially Aged Microplastics and Subsequent Release in Simulated Gastrointestinal Fluid | Microplastics, especially aged microplastics can become vectors of heavy metals from environment to organisms with potential negative effects on food chain. However, a few studies focused on the bioavailability of adsorbed metals and most studies related to aged microplastics used artificial method that cannot entirely reflect actual aging processes. In this study, virgin polystyrene was aged by ozone (PS-O3), solar simulator (PS-SS) and lake (PS-Lake) to investigate adsorption of Cu by virgin, artificially and naturally aged microplastics and subsequent release in simulated gastrointestinal fluids (SGF). Characterization results show carbonyl was formed in PS-O3 and PS-SS, and the oxidation degree was PS-O3> PS-SS> PS-Lake. However, Cu adsorption capacity followed this order PS-Lake (158 μg/g)> PS-SS (117 μg/g)> PS-O3 (65 μg/g)> PS-Virgin (0). PS-O3 showed highest Cu adsorption capacity at 0.5 h (71 μg/g), but it dropped dramatically later (10 μg/g, 120 h), because PS-O3 could break up and the adsorbed Cu released in solutions subsequently. For PS-Lake, precipitation of metallic oxides contributes to the accumulation of Cu. The addition of dissolved organic matter (DOM) could occupy adsorption sites on PS and compete with Cu, but also can attach PS and adsorb Cu due to its rich functional groups. The simultaneous ingestion of microplastics with food suggested that adsorbed Cu is solubilized mostly from aged PS to SGF. | Lu Zhou; Thibault Masset; Florian Breider | Earth, Space, and Environmental Chemistry; Environmental Science | CC BY NC ND 4.0 | CHEMRXIV | 2023-08-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64db282f69bfb8925af4df3d/original/adsorption-of-copper-by-naturally-and-artificially-aged-microplastics-and-subsequent-release-in-simulated-gastrointestinal-fluid.pdf |
60c741a50f50dbc102395b46 | 10.26434/chemrxiv.8069042.v1 | Microwave-Assisted Decarbonylation of Biomass-Derived Aldehydes Using Pd-Doped Hydrotalcites | <p>Here we report the synthesis, characterization and
activity of tunable Pd-doped hydrotalcites (Pd-HTs) for the decarbonylation of
furfural, hydroxymethylfurfural (HMF),
aromatic and aliphatic aldehydes under microwave conditions. The
decarbonylation activity reported is a notable improvement over prior
heterogeneous catalysts for this process. Furfural decarbonylation is optimized
in a benign solvent compatible with biomass processing - ethanol, under
relatively mild conditions and short reaction times. HMF selectively affords
excellent yields of furfuryl alcohol with no humin formation, but longer
reaction can also afford furan via tandem alcohol dehydrogenation and
decarbonylation. Yields of substituted benzaldehydes are related to calculated
Mulliken charge of the carbonyl carbon. The activity and selectivity
differences can be traced to loading-dependent differences in Pd speciation on
the catalysts. Poisoning studies show inverse correlation between Pd loading
and metal leaching: Pd-HTs with lowest Pd loading, which consist of highly
dispersed and oxidized Pd species, operate heterogeneously with
negligible metal leaching. Recycling experiments
are consistent with this trend, offering potential for further optimization to
improve robustness.</p> | Nan An; Diana Ainembabazi; Kavya Samudrala; Christopher Reid; Karen Wilson; Adam Lee; Adelina Voutchkova-Kostal | Base Catalysis; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2019-05-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c741a50f50dbc102395b46/original/microwave-assisted-decarbonylation-of-biomass-derived-aldehydes-using-pd-doped-hydrotalcites.pdf |
628e3f1259f0d643b99d1fd6 | 10.26434/chemrxiv-2022-d801x | One-Pot Two-Step Catalytic Synthesis of Rationally Designed 6-amino-2-pyridone-3,5-dicarbonitriles Enabling Anti-Cancer Bioactivity | Herein we report a one-pot two-step synthesis of a bioactive 6-amino-2-pyridone-3,5-dicarbonitrile derivative using natural product catalysts betaine and guanidine carbonate. Upon identification of the anticancer bioactivity of the compound, we carried out structure-activity relationship and rationally designed a library of 16 derivatives. Out of the compounds, 5o had the most potent anti-cancer activity against murine glioblastoma cell lines and was selected for further study. Compound 5o showed anti-cancer properties against liver, breast, lung as well as primary patient-derived glioblastoma cell lines. Furthermore, 5o in combination with specific clinically relevant brain-penetrant small molecule inhibitors induces enhanced cytotoxicity in a murine glioblastoma cell line. Through our current work, we establish a promising 6-amino-2-pyridone-3,5-dicarbonitrile based lead compound with anti-cancer activity either on its own or in combination with specific clinically relevant small molecule kinase and proteasome inhibitors. | Lynden G Nicely; Ruturajsinh M Vala; Dipti B Upadhyay; Joaquina Nogales; Celestine Chi; Sourav Banerjee; Hitendra M Patel | Biological and Medicinal Chemistry; Chemical Biology; Drug Discovery and Drug Delivery Systems | CC BY NC ND 4.0 | CHEMRXIV | 2022-05-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/628e3f1259f0d643b99d1fd6/original/one-pot-two-step-catalytic-synthesis-of-rationally-designed-6-amino-2-pyridone-3-5-dicarbonitriles-enabling-anti-cancer-bioactivity.pdf |
60c74021f96a001271286233 | 10.26434/chemrxiv.7637405.v1 | Pseudoboehmite Nanorod–Polymethylsilsesquioxane Monoliths Formed by Colloidal Gelation | The addition of a trifunctional silicon alkoxide methyltrimethoxysilane (MTMS) to aluminum oxide hydroxide pseudoboehmite nanorod (PBNR) aqueous dispersions resulted in adhesion between the PBNR colloids to form macroporous monoliths. The use of greater amounts of MTMS led to coarsening of the skeleton and strengthening of the skeletal structure, and the monoliths got water resistance. When a dispersion of zirconium oxide nanoparticles and MTMS was used as a starting material, a macroporous monolith was also obtained by the same simple process. The colloidal gelation occurs because the silanol moiety is more likely to react with the colloid surface of ceramic materials than with other silanols derived from MTMS and their oligomer. Due to the development of material chemistry, colloidal dispersions having various shapes and compositions are becoming available as products. Based on this mechanism, it is expected to be feasible to fabricate various porous monoliths with characteristic morphologies and properties depending on the colloid.<br /> | Gen Hayase | Ceramics; Materials Processing; Nanostructured Materials - Materials; Physical and Chemical Processes; Structure | CC BY NC ND 4.0 | CHEMRXIV | 2019-01-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74021f96a001271286233/original/pseudoboehmite-nanorod-polymethylsilsesquioxane-monoliths-formed-by-colloidal-gelation.pdf |
6793a46afa469535b9a8b82d | 10.26434/chemrxiv-2025-0tns5-v2 | Atomic Layer Deposition of AlxTi1-xN via Co-evaporation of Metal Precursors | Different approaches are used in tailoring properties of thin films to meet requirements for specific applications. This study comprises work done on atomic layer deposition (ALD) of AlxTi1-xN employing the co-evaporation approach using tris-dimethylamido aluminum (TDMAA, Al(NMe2)3) and tetrakis(dimethylamido)titanium(IV) (TDMAT, Ti(NMe2)4), and ammonia (NH3) plasma. High Al-content, low impurity (O and C, both <5 at.%) films with uniform grain size distribution and dense morphology were deposited. The as-deposited films were X-ray amorphous, but mixed crystallographic phases were observed when the films were annealed at 700 °C. The deposited aluminum rich AlxTi1-xN films show an alternative way for ternary material depositions. | Pamburayi Mpofu; Pentti Niiranen; Oscar Alm; Jonas Lauridsen; Tommy Larsson; Henrik Pedersen | Materials Science; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2025-01-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6793a46afa469535b9a8b82d/original/atomic-layer-deposition-of-alx-ti1-x-n-via-co-evaporation-of-metal-precursors.pdf |
6448ea1ce4bbbe4bbf4671cc | 10.26434/chemrxiv-2023-5jlzx | Unraveling the Structural and Property Differences Between Highly Similar Chiral and Racemic Crystals Composed of Analogous Molecules | The structural differences between chiral and racemic crystals of enantiomers have piqued interest, as exemplified by the classical Wallach's rule. However, the mechanical and thermal disparities between these materials have not been thoroughly investigated. This study reports the structural and mechanical differences between chiral and racemic crystals of two analogous molecules. The similarity of molecular and crystal structures between the two analogs was validated through comparison with known chiral-racemic crystal pairs. The Young's moduli of the four crystals revealed larger values for racemic crystals than their chiral counterparts, consistent with the intermolecular interaction energies projected along the loading direction. The thermal response of crystals plays a significant role in their elastic behavior, and the temperature dependence of interaction energies along [001] direction was found to agree with the temperature dependence of lattice dynamics for all four crystals. | Kazuki Ishizaki; Daisuke Takagi; Toru Asahi; Masahiro Kuramochi; Takuya Taniguchi | Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-04-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6448ea1ce4bbbe4bbf4671cc/original/unraveling-the-structural-and-property-differences-between-highly-similar-chiral-and-racemic-crystals-composed-of-analogous-molecules.pdf |
66b53d5701103d79c5467d65 | 10.26434/chemrxiv-2024-m9px9 | Hijacking the MDM2 E3 Ligase with novel BRD4-Targeting PROTACs in Pancreatic Cancer Cells | The phenotypic effect induced by a Proteolysis-Targeting Chimera (PROTAC) can depend on several factors, including the E3 ligase recruited. For the discovery of a first-in-class PROTAC for a target of interest, the E3 ligases commonly hijacked remain the Von Hippel-Lindau (VHL) and Cereblon (CRBN) since potent and accessible ligands are readily available to recruit them. Mouse double minute 2 (MDM2) E3 ligase stands out because it regulates p53 levels to maintain cellular homeostasis. However, the synthesis of the most potent MDM2 ligands remains very complex. Here we report the discovery of novel MDM2-recruiting PROTACs incorporating rac-Nutlin-3 as a ligand with an easier synthetic tractability, further demonstrating its potential in this technology. The most promising degrader, PROTAC 3, showed preferential degradation of the BRD4 short isoform and c-Myc compared with MZ1, a validated VHL-based PROTAC. | Mihaela Ficu; Dan Niculescu-Duvaz; Mohammed Aljarah; Christopher S. Kershaw; Caroline J. Springer | Biological and Medicinal Chemistry; Organic Chemistry; Organic Synthesis and Reactions; Chemical Biology; Drug Discovery and Drug Delivery Systems | CC BY NC ND 4.0 | CHEMRXIV | 2024-08-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66b53d5701103d79c5467d65/original/hijacking-the-mdm2-e3-ligase-with-novel-brd4-targeting-prota-cs-in-pancreatic-cancer-cells.pdf |
60c740e3567dfe36f8ec3c8b | 10.26434/chemrxiv.6204167.v2 | An Improved Free Energy Perturbation FEP+ Sampling Protocol for Flexible Ligand-Binding Domains | Recent improvements to free energy perturbation (FEP) calculations, especiallyFEP+, established their utility for pharmaceutical lead optimization. However, to dateFEP has typically been helpful only when (1) high-quality X-ray data is available and(2) the target protein does not undergo significant conformational changes. Also, alack of systematic studies on determining an adequate sampling time is often one ofthe primary limitations of FEP calculations. Herein, we propose a modified versionof the FEP/REST (i.e., replica exchange with solute tempering) sampling protocol,based on systematic studies on several targets by probing a large number of permutations with different sampling schemes. Improved FEP+ binding affinity predictions for regular flexible-loop (F-loop) motions and considerable structural changes can be obtained by extending the pre-REST sampling time from 0.24 ns to 5 ns/λand 2×10 ns/λ, respectively. We obtained much more precise ∆∆G calculations of the individual perturbations, including the sign of the transformations and less error. We extended the REST simulations from 5 ns to 8 ns to achieve reasonable free energy convergence.Implementing REST to the entire ligand as opposed to solely the perturbed region, and also some important flexible protein residues (pREST region) in ligand binding domain (LBD) , also considerably improved the FEP+ results in most of the studied cases. Preliminary molecular dynamics (MD) runs were useful for establishing the correct binding mode of the compounds and thus precise alignment for FEP+.<br /> | Filip Fratev; suman sirimulla | Chemical Biology; Drug Discovery and Drug Delivery Systems; Computational Chemistry and Modeling; Theory - Computational; Biophysical Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2019-02-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c740e3567dfe36f8ec3c8b/original/an-improved-free-energy-perturbation-fep-sampling-protocol-for-flexible-ligand-binding-domains.pdf |
60c74c6a0f50db0128396e58 | 10.26434/chemrxiv.12477449.v1 | Natural Abundance Oxygen-17 Solid-State NMR of Metal Organic Frameworks Enhanced by Dynamic Nuclear Polarization | The <sup>17</sup>O resonances of Zirconium-oxo clusters
that can be found in porous Zr carboxylate metal-organic frameworks (MOFs) have
been investigated by magic-angle spinning (MAS) NMR spectroscopy enhanced by
dynamic nuclear polarization (DNP). High-resolution <sup>17</sup>O spectra at 0.037
% natural abundance could be obtained in 48 hours, thanks to DNP enhancement of
the <sup>1</sup>H polarization by factors e(<sup>1</sup>H) = S<sub>with</sub>/S<sub>without
</sub>= 28, followed by <sup>1</sup>H®<sup>17</sup>O cross-polarization, allowing a
saving in experimental time by a factor of <i>ca</i>.
800. The
distinct <sup>17</sup>O sites from the oxo-clusters can be resolved at 18.8 T.
Their assignment is supported by density functional theory (DFT) calculations
of chemical shifts and quadrupolar parameters. | Diego Carnevale; Georges Mouchaham; Sujing Wang; Mathieu Baudin; Christian Serre; Geoffrey Bodenhausen; Daniel Abergel | Spectroscopy (Physical Chem.); Structure | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74c6a0f50db0128396e58/original/natural-abundance-oxygen-17-solid-state-nmr-of-metal-organic-frameworks-enhanced-by-dynamic-nuclear-polarization.pdf |
6358d308311072fe4cf03573 | 10.26434/chemrxiv-2022-zk61r | Disproportionation and ligand lability in low oxidation state boryl-tin chemistry | Boryltin compounds featuring the metal in the +1 or 0 oxidation states can be synthesized from the carbene-stabilized tin(II) bromide (boryl)Sn(NHC)Br (boryl = {B(NDippCH)2}; NHC = C{(NiPrCMe)2}) by the use of strong reducing agents. The formation of the mono-carbene stabilized distannyne and donor-free distannide systems (boryl)SnSn(IPrMe)(boryl) (2) and K2[Sn2(boryl)2], (3) using Mg(I) and K reducing agents mirrors related germanium chemistry. In contrast to their lighter congeners, however, systems of the type [Sn(boryl)]n are unstable with respect to disproportionation. Carbene abstraction from 2 using BPh3, and two-electron oxidation of 3 both result in the formation of a 2:1 mixture of the Sn(II) compound Sn(boryl)2, and the hexatin cluster, Sn6(boryl)4 (4). A viable mechanism for this rearrangement is shown by quantum chemical studies to involve a vinylidene intermediate (analogous to the isolable germanium compound, (boryl)2Ge=Ge), which undergoes facile atom transfer to generate Sn(boryl)2 and trinuclear [Sn3(boryl)2]. The latter then dimerizes to give the observed hexametallic product 4, with independent studies also showing that similar trigermanium species aggregate in analogous fashion. | Xiongfei Zheng; Agamemnon Crumpton; Andrey Protchenko; Andreas Heilmann; Mathias Ellwanger; Simon Aldridge | Inorganic Chemistry; Main Group Chemistry (Inorg.) | CC BY NC ND 4.0 | CHEMRXIV | 2022-10-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6358d308311072fe4cf03573/original/disproportionation-and-ligand-lability-in-low-oxidation-state-boryl-tin-chemistry.pdf |
650010cd99918fe537cf6d0b | 10.26434/chemrxiv-2023-3zhx3 | Coupling of phthalocyanines with plasmonic gold nanoparticles by click chemistry for an enhanced singlet oxygen based photoelectrochemical sensing | Coupling photosensitizers (PSs) with plasmonic nanoparticles increases the photocatalytic activity of PSs as the localized surface plasmon resonance (LSPR) of plasmonic nanoparticles leads to extreme concentration of light in their vicinity known as the near-field enhancement effect. To realize this in a colloidal phase, efficient conjugation of the PS molecules with the plasmonic nanoparticle surface is critical. In this work, we demonstrate the coupling of phthalocyanine (Pc) molecules with gold nanoparticles (AuNPs) in the colloidal phase via click chemistry. This conjugated Pc-AuNPs colloidal system is shown to enhance the photocatalytic singlet oxygen (1O2) production over non-conjugated Pcs and hence improve the photoelectrochemical detection of phenols. The plasmonic enhancement of the 1O2 generation by Pcs was clearly elucidated by complementary experimental and computational classical electromagnetic models. The dependence of plasmonic enhancement on the spectral position of the excitation laser wavelength and the absorbance of the Pc molecules with respect to the wavelength specific near-field enhancement is clearly demonstrated. A high ∼ 8 times enhancement is obtained with green laser (532 nm) at the LSPR due to the maximum near-field enhancement at the resonance wavelength. | Shahid Ullah Khan; Refilwe Matshitse; Rituraj Borah; Manjunatha Nemakal; Ekaterina O. Moiseeva; Tatiana Dubinina; Tebello Nyokong; Sammy Verbruggen; Karolien De Wael | Analytical Chemistry | CC BY 4.0 | CHEMRXIV | 2023-09-14 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/650010cd99918fe537cf6d0b/original/coupling-of-phthalocyanines-with-plasmonic-gold-nanoparticles-by-click-chemistry-for-an-enhanced-singlet-oxygen-based-photoelectrochemical-sensing.pdf |
60c74703bdbb890244a38cec | 10.26434/chemrxiv.11374785.v1 | The Role of Atomic Carbon in Directing Electrochemical CO(2) Reduction to Multicarbon Products | Electrochemical reduction of
carbon-dioxide/carbon-monoxide (CO<sub>(2)</sub>R) to fuels and chemicals
presents an attractive approach for sustainable chemical synthesis, but also
poses a serious challenge in catalysis. Understanding the key aspects that
guide CO<sub>(2)</sub>R towards value-added multicarbon (C<sub>2+</sub>)
products is imperative in designing an efficient catalyst. Herein, we identify
the critical steps toward C<sub>2</sub> products on copper through a
combination of energetics from density functional theory and micro-kinetic
modeling. We elucidate the importance of atomic carbon in directing C<sub>2+</sub>
selectivity and how it introduces surface structural sensitivity on copper
catalysts. This insight enables us to propose two simple thermodynamic
descriptors that effectively describe C<sub>2+</sub> selectivity on metal
catalysts beyond copper and hence it identifies an intelligible protocol to
screen for materials that selectively catalyze CO<sub>(2)</sub> to C<sub>2+</sub>
products. | Hongjie Peng; Michael Tang; Xinyan Liu; Philomena Schlexer Lamoureux; Michal Bajdich; Frank Abild-Pedersen | Reaction Engineering; Electrocatalysis; Heterogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2019-12-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74703bdbb890244a38cec/original/the-role-of-atomic-carbon-in-directing-electrochemical-co-2-reduction-to-multicarbon-products.pdf |
60d67fb0e2113353d3e0d2c4 | 10.26434/chemrxiv-2021-sm7vw | The Sea Spray Chemistry and Particle Evolution Study (SeaSCAPE): Overview and Experimental Methods | Marine aerosols strongly influence climate through their interactions with solar radiation and clouds. However, significant questions remain regarding the influences of biological activity and seawater chemistry on the flux, chemical composition, and climate-relevant properties of marine aerosols and gases. Wave channels, a traditional tool of physical oceanography, have been adapted for large-scale ocean-atmosphere mesocosm experiments in the laboratory. These experiments enable the study of aerosols under controlled conditions which isolate the marine system from atmospheric anthropogenic and terrestrial influences. Here, we present an overview of the 2019 Sea Spray Chemistry and Particle Evolution (SeaSCAPE) study, which was conducted in an 11,800 L wave channel which was modified to facilitate atmospheric measurements. The SeaSCAPE campaign sought to determine the influence of biological activity in seawater on the production of primary sea spray aerosols, volatile organic compounds (VOCs), and secondary marine aerosols. Notably, the SeaSCAPE experiment also focused on understanding how photooxidative aging processes transform the composition of marine aerosols. In addition to a broad range of aerosol, gas, and seawater measurements, we present key results which highlight the experimental capabilities during the campaign, including the phytoplankton bloom dynamics, VOC production, and the effects of photochemical aging on aerosol production, morphology, and chemical composition. Additionally, we discuss the modifications made to the wave channel to improve aerosol production and reduce background contamination, as well as subsequent characterization experiments. The SeaSCAPE experiment provides unique insight into the connections between marine biology, atmospheric chemistry, and climate-relevant aerosol properties, and demonstrates how an ocean-atmosphere-interaction facility can be used to isolate and study reactions in the marine atmosphere in the laboratory under more controlled conditions. | Jonathan Sauer; Kathryn Mayer; Christopher Lee; Michael Alves; Sarah Amiri; Cristina Bahaveolos; Emily Barnes; Daniel Crocker; Julie Dinasqauet; Lauren Garofalo; Chathuri Kaluarachchi; Duyen Dang; Delaney Kilgour; Liora Mael; Brock Mitts; Daniel Moon; Clare Morris; Alexia Moore; Chi-min Ni; Matthew Pendergraft; Daniel Petras; Rebecca Simpson; Stephanie Smith; Paul Tumminello; Joseph Walker; Paul Demott; Delphine Farmer; Allen Goldstein; Vicki Grassian; Jules Jaffe; Francesca Malfatti; Todd Martz; Jonathan Slade; Alexei Tivanski; Timothy Bertram; Christopher Cappa; Kimberly Prather | Analytical Chemistry; Earth, Space, and Environmental Chemistry; Atmospheric Chemistry; Environmental Science | CC BY NC ND 4.0 | CHEMRXIV | 2021-06-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60d67fb0e2113353d3e0d2c4/original/the-sea-spray-chemistry-and-particle-evolution-study-sea-scape-overview-and-experimental-methods.pdf |
60c7597a4c89198350ad4d8f | 10.26434/chemrxiv.13567328.v2 | Crystal Structure and Optical Properties of a Homometallic Heterotrinuclear Europium(III) Complex – a Cationic Eu(III) ion Coordinated by two [Eu(III)DOTA]- Complexes | The structure and solid state luminescence properties of a homometallic heterotrinuclear [Eu(μO)5(OH2)3][Eu(DOTA)(H2O)]2Cl crystal was determined and was found to have two sites: a free europium(III) ion and a [Eu(DOTA)(H2O)]- complex. The trinuclear compound crystallizes in a laminar structure in triclinic space group P. The crystal structure was determined using complex data treatment due to non-merohedric twinning. Experimental data sets were recorded with large redundancy and separated according to scattering domain in order to obtain a reliable structure, which revealed the configuration of the europium(III) sites. In first site, the europium(III) 1,4,7,10-tetrazacyclododecane-1,4,7,10-tetraacetate (Eu.DOTA) complex was found to adopt a capped twisted square antiprismatic (cTSAP) conformation, where a capping water molecule increased the coordination number of the europium(III) site to nine (CN = 9). In the second site, the cationic europium(III) ion was found to be coordinated by three water molecules and five oxy groups from neighboring [Eu(DOTA)(H2O)]- complexes. The coordination geometry of this site was found to be a compressed square antiprism (SAP), and the coordination number of the europium(III) ion was found to be eight (CN = 8). A large increase in rate constant of luminescence was observed for Eu(III) in [Eu(DOTA)(H2O)]- in solid state luminescence spectroscopy measurements compared to in solution, which lead to investigations of single-crystals in deuterated media to exclude additional effects of quenching. We conclude that the most probable cause of the decrease in observed luminescence lifetimes is the high asymmetry of the coordination environment of [Eu(DOTA)(D2O)]- in the [Eu(μO)5(OD2)3][Eu(DOTA)(D2O)]2Cl crystals<br /> | Maria Storm Thomsen; Ander Østergård Madsen; Thomas Just Sørensen | Lanthanides and Actinides | CC BY NC ND 4.0 | CHEMRXIV | 2021-05-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7597a4c89198350ad4d8f/original/crystal-structure-and-optical-properties-of-a-homometallic-heterotrinuclear-europium-iii-complex-a-cationic-eu-iii-ion-coordinated-by-two-eu-iii-dota-complexes.pdf |
60c74a31bdbb896d97a39320 | 10.26434/chemrxiv.12156747.v1 | Potent and Selective N-Terminal BRD4 Bromodomain Inhibitors by Targeting Non-Conserved Residues and Structured Water Displacement | This manuscript focuses on the structure-based design of selective inhibitors of the first bromodomain of BRD4. This manuscript uses describes organic synthesis to make inhibitors, and biophysical analysis to evaluate their inhibitor potency in competive inhibition assays (fluorescence anisotropy assays and AlphaScreen). Binding mode is evaluate from protein co-crystal structures. Cell activity is evaluated in cell viability assays, target engagement CETSA assays analyzed via western blot, and inhibition of Myc via western blot analysis. | Huarui Cui; Anand Divakaran; Anil K. Pandey; Jorden
A. Johnson; huda zahid; zachary hoell; mikael ellingson; ke shi; Hideki Aihara; Daniel A. Harki; william pomerantz | Biochemistry; Chemical Biology; Drug Discovery and Drug Delivery Systems | CC BY NC ND 4.0 | CHEMRXIV | 2020-04-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74a31bdbb896d97a39320/original/potent-and-selective-n-terminal-brd4-bromodomain-inhibitors-by-targeting-non-conserved-residues-and-structured-water-displacement.pdf |
60c753daee301c08ccc7ae9c | 10.26434/chemrxiv.12508229.v2 | Benchmarking Coordination Number Prediction Algorithms on Inorganic Crystal Structures | Coordination numbers and geometries form a theoretical framework for understanding and predicting materials properties. Algorithms to determine coordination numbers automatically are increasingly used for machine learning and automatic structural analysis. In this work, we introduce MaterialsCoord, a benchmark suite containing 56 experimentally-derived crystal structures (spanning elements, binaries, and ternary compounds) and their corresponding coordination environments as described in the research literature. We also describe CrystalNN, a novel algorithm for determining near neighbors. We compare CrystalNN against 7 existing near-neighbor algorithms on the MaterialsCoord benchmark, finding CrystalNN to perform similarly to several well-established algorithms. For each algorithm, we also assess computational demand and sensitivity towards small perturbations that mimic thermal motion. Finally, we investigate the similarity between bonding algorithms when applied to the Materials Project database. We expect that this work will aid the development of coordination prediction algorithms as well as improve structural descriptors for machine learning and other applications. | Hillary Pan; Alex Ganose; Matthew Horton; Muratahan Aykol; Kristin Persson; Nils Zimmermann; Anubhav Jain | Bonding; Coordination Chemistry (Inorg.); Theory - Inorganic; Theory - Computational; Crystallography; Crystallography – Inorganic | CC BY NC ND 4.0 | CHEMRXIV | 2021-01-05 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c753daee301c08ccc7ae9c/original/benchmarking-coordination-number-prediction-algorithms-on-inorganic-crystal-structures.pdf |
60c74d14702a9b32bc18b7be | 10.26434/chemrxiv.12584930.v1 | A Database Framework for Rapid Screening of Structure-Function Relationships in PFAS Chemistry | This paper describes a database framework that enables one to rapidly explore systematics in structure-function relationships associated with new and emerging PFAS chemistries. The data infrastructure maps high dimensional information associated with SMILES encoding of molecular structure with activity/property data. This ‘PFAS-Map’ serves as a 3-dimensional unsupervised visualization learning tool to automatically classify new PFAS chemistries into current well-established criteria for PFAS classification. We provide examples on how the PFAS-Map can be utilized, including the ability to predict and estimate yet unmeasured fundamental physical properties of PFAS chemistries, uncovering hierarchical characteristics in existing classification schemes and the fusion of data from diverse sources. | An Su; Krishna Rajan | Environmental Science; Chemoinformatics; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2020-07-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74d14702a9b32bc18b7be/original/a-database-framework-for-rapid-screening-of-structure-function-relationships-in-pfas-chemistry.pdf |
679a5a226dde43c908ddce1c | 10.26434/chemrxiv-2025-t6pdx | Parallel and flow photoredox chemistry enabled by advanced temperature-controlled photoreactors | Despite remarkable advancements in recent years, photoredox catalysis still faces reproducibility and scalability issues, hindering its widespread adoption in academic and industrial research. In this work, we address some of these challenges by introducing temperature-controlled modular photoreactors suitable for micro- and millimolar-scale syntheses in batch and flow. These photoreactors demonstrate a remarkable ability to precisely control internal temperature of irradiated reaction mixtures in the range from -20 °C up to +80 °C. The use of the same cooling concept and the light source ensures not only remarkable reproducibility across all positions in the batch photoreactors but also enables a seamless transfer of reaction conditions from the microscale 96-positions photoreactor (96xPR) to the flow photoreactors. By using the 96xPR, we successfully conducted screening campaigns for photoredox C‒C and C‒N couplings on a scale as little as 2 µmol. We are confident that the technological advancements detailed in this work, which we freely provide for replication, will expedite the development of photoredox chemistry in both academic and industrial settings. | Oleg Borodin; Matthias Schmid | Organic Chemistry; Chemical Engineering and Industrial Chemistry; Organic Synthesis and Reactions; Photochemistry (Org.); Pharmaceutical Industry | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/679a5a226dde43c908ddce1c/original/parallel-and-flow-photoredox-chemistry-enabled-by-advanced-temperature-controlled-photoreactors.pdf |
675bb127085116a1333df326 | 10.26434/chemrxiv-2024-rjbdc-v3 | Power strokes in molecular motors: Predictive, irrelevant, or somewhere in between? | For several decades, molecular motor directionality has been rationalized in terms of the free energy of molecular conformations visited before and after the motor takes a step, a so-called power stroke mechanism with analogues in macroscopic engines. Despite theoretical and experimental demonstrations of its flaws, the power stroke language is quite ingrained, and some communities still value power stroke intuition. By building a catalysis-driven motor into simulated numerical experiments, we here systematically report on how directionality responds when the motor is modified accordingly to power stroke intuition. We confirm that the power stroke mechanism generally does not predict motor directionality. Nevertheless, the simulations illustrate that the relative stability of molecular conformations should be included as a potential design element to adjust the motor directional bias. Though power strokes are formally unimportant for determining directionality, we show that practical attempts to alter a power stroke have side effects that can in fact alter the bias. The change in the bias can align with what power stroke intuition would have suggested, offering a potential explanation for why the flawed power stroke mechanism can retain apparent utility when engineering specific systems. | Emanuele Penocchio; Geyao Gu; Alex Albaugh; Todd R. Gingrich | Theoretical and Computational Chemistry; Physical Chemistry; Nanoscience; Computational Chemistry and Modeling; Chemical Kinetics; Statistical Mechanics | CC BY NC 4.0 | CHEMRXIV | 2024-12-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/675bb127085116a1333df326/original/power-strokes-in-molecular-motors-predictive-irrelevant-or-somewhere-in-between.pdf |
67220b85f9980725cf7466d1 | 10.26434/chemrxiv-2024-91vb5 | General Data Management Workflow to Process Tabular Data in Automated and High
throughput Heterogeneous Catalysis Research | Data management and processing are crucial steps to implement streamlined and
standardized data workflows for automated and high-throughput laboratories. Electronic
laboratory notebooks (ELNs) have proven to be effective to manage data in combination with
a laboratory information management system (LIMS) to connect data and inventory. However,
streamlined data processing does still pose a challenge on an ELN especially with large data.
Herein we present a Python library that allows to streamline and automate data management
of tabular data generated within a data-driven, automated high-throughput laboratory with a
focus on heterogeneous catalysis R&D. This approach speeds up data processing and avoids
errors introduced by manual data processing. Through the Python library, raw data from
individual instruments related to a project are downloaded from an ELN, merged in a
relational database fashion, processed and re-uploaded back to the ELN. Straightforward data
merging is especially important, since information stemming from multiple devices needs to
be processed together. By providing a configuration file that contain all the data management
information, data merging and processing of individual data sources is executed. Having
established streamlined data management workflows allows to standardize data handling and
contributes to the implementation and use of open research data following Findable,
Accessible, Interoperable and Reusable (FAIR) principles in the field of heterogeneous
catalysis. | Erwin Lam; Tanguy Maury; Sebastian Preiss; Yuhui Hou; Hannes Frey; Caterina Barillari; Paco Laveille | Catalysis; Heterogeneous Catalysis | CC BY NC 4.0 | CHEMRXIV | 2024-11-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67220b85f9980725cf7466d1/original/general-data-management-workflow-to-process-tabular-data-in-automated-and-high-throughput-heterogeneous-catalysis-research.pdf |
67b2508a81d2151a02c21142 | 10.26434/chemrxiv-2025-k7kz4 | Multi-material filaments for 3D printing of photoelectrocatalytic carbon nitride composites | 3D printing of conductive structures via fused deposition modelling has emerged as a mainstream manufacturing technique for electrochemical devices owing to the affordability and availability of thermoplastic-carbon-based filaments. On the current market, the existing filaments are limited in terms of their electrical conductivity and functionality. To address this, the development of multi-material filaments incorporating additional functional materials along with conductive carbons strategically produces 3D-printed electrodes with enhanced functionalities. In parallel, filament fabrication allows for precise control over the material composition and properties, such as chemical, thermal, and mechanical properties of the filament. In this work, we explored the fabrication of a multi-material filament combining photocatalytic carbon nitride, C3N4, and conductive carbon nanotubes, CNTs. Our C3N4-CNTs electrodes 3D-printed from it outperformed CNTs electrodes in hydrogen evolution and photocatalytic degradation of an organic dye. Our findings suggest that multi-material filaments may transcend the current filament-extrusion printing technique and expand its potential beyond electrochemistry. | Timo Uhlein; Yana Reva; Martin Dierner; Johannes Will; Kirill Gubanov; Michael Moritz; Florian Winkler; Daniel Langford; Dirk M. Guldi; Christian Papp; Rainer H. Fink; Julien Bachmann; Erdmann Spiecker; Pablo Jiménez-Calvo; Mario Palacios-Corella; Siowwoon Ng | Physical Chemistry; Materials Science; Carbon-based Materials; Materials Processing; Nanostructured Materials - Materials; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2025-02-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67b2508a81d2151a02c21142/original/multi-material-filaments-for-3d-printing-of-photoelectrocatalytic-carbon-nitride-composites.pdf |
672d47a25a82cea2fa6fe8d8 | 10.26434/chemrxiv-2024-mj9gg | Surfactant Control of Interfacial Reaction Rates in Aqueous Microdroplets | Microdroplets are purported to enhance reaction rates and produce spontaneous chemical transformations that are unfavorable in macroscale systems. The gas-liquid interface is widely implicated for the emergence of these chemical anomalies. Experiments conducted on individual microdroplets provide a unique platform for studying interfacial effects while bypassing transport limitations often encountered in macroscopic systems. We investigate such interfacial effects by analyzing the suppression of the I- + O3 surface reaction by the nonionic surfactant Triton X-100 in an array of levitated microdroplets. Using a novel kinetic framework describing surface and bulk reactivity, we find that increasing surfactant concentration shifts the locus of reaction from the top-most nanometer of the interface to a subsurface region located < 2 nm below the surface. This detailed picture of spatial reactivity is afforded only by considering the timescales for O3 adsorption and solvation combined with reaction monitoring in single microdroplets. Chemical uniqueness is further illustrated by the I- + O3 rate dependence on [Triton X-100], which is quantitatively understood by considering finite size effects in microdroplets. Both size and surface effects are considered to derive an analytical expression for reactive uptake of O3 which demonstrates the role of competitive adsorption of Triton-X and I- at the gas-liquid interface. This work establishes a novel approach to understanding interfacial reaction kinetics that successfully links nanometer-scale dynamics from molecular simulations with macroscale measurements of surface tension and microscale measurements of chemical reactivity. | Alexander Prophet; David Limmer; Kevin Wilson | Physical Chemistry; Analytical Chemistry; Earth, Space, and Environmental Chemistry; Mass Spectrometry; Chemical Kinetics; Interfaces | CC BY NC ND 4.0 | CHEMRXIV | 2024-11-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/672d47a25a82cea2fa6fe8d8/original/surfactant-control-of-interfacial-reaction-rates-in-aqueous-microdroplets.pdf |
60c751d5ee301ca3aac7ab1b | 10.26434/chemrxiv.13214567.v1 | Atmospheric Pressure Single Photon Laser Ionization (APSPLI) Mass Spectrometry Using a 157 Nm Fluorine Excimer Laser for Sensitive and Selective Detection of Non- to Semi-Polar Hydrocarbons | In this study, atmospheric pressure single photon ionization (APSPLI) mass spectrometry utilizing a fluorine excimer laser operated at 157 nm (7.9 eV) is presented for the first time. For evaluation and optimization, PAH standard mixtures introduced by gas chromatography were used. Atmospheric pressure laser ionization (APLI) approaches with laser wavelengths above 200 nm induce a multiphoton process, and ionization yields are strongly dependent on the heteroatom-content and isomeric structure. The presented technique using VUV photons allowed for the selective ionization of semi- to non-polar compounds in a single photon ionization process. Consequently, molecular radical cations were found as base peak, whereas protonated species were almost absent. Even though the ionization chamber is flushed by a high flow of pure nitrogen, remaining oxygen and water traces caused several side-reactions, leading to unwanted oxidized ionization artifacts. Installation of a water and oxygen filter cartridge significantly reduced the abundance of those artifacts, whereas the laser beam position was found to have a substantially lower effect. For evaluating complex mixture analysis, APSPLI was applied to characterize a light crude oil subjected to the ionization source by thermogravimetry and gas chromatography hyphenation. In addition to aromatic hydrocarbons, APSPLI also allowed for the sensitive ionization of sulfur-containing aromatic constituents, and even species with two sulfur-atoms could be detected. A comparison of APSPLI to APLI conducted at 266 nm revealed the additional compositional space accessible by the single photon process. This novel ionization concept is envisioned to have a high analytical potential further explored in the future.<br /> | Christopher Rüger; Anika Neumann; Martin Sklorz; Ralf Zimmermann | Analytical Chemistry - General; Mass Spectrometry | CC BY NC ND 4.0 | CHEMRXIV | 2020-11-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c751d5ee301ca3aac7ab1b/original/atmospheric-pressure-single-photon-laser-ionization-apspli-mass-spectrometry-using-a-157-nm-fluorine-excimer-laser-for-sensitive-and-selective-detection-of-non-to-semi-polar-hydrocarbons.pdf |
650cbd0f60c37f4f763792ef | 10.26434/chemrxiv-2022-zrzmf-v5 | Towards Determining Amyloid Fibril Structures Using Experimental Constraints from Raman Spectroscopy | We present structural models for three different amyloid fibril polymorphs prepared from amylin20−29 (sequence SNNFGAILSS) and amyloid-β25−35 (Aβ25−35) (sequence GSNKGAIIGLM) peptides. These models are based on amide C=O bond and Ramachandran ψ-dihedral angle data from Raman spectroscopy, which were used structural constraintsto guide molecular dynamics (MD) simulations. The resulting structural models indicate that the basic structural motif of amylin20−29 and Aβ25−35 fibrils are extended β-strands. Our data indicates that amylin20−29 forms both antiparallel and parallel β-sheet fibril polymorphs, while Aβ25−35 forms a parallel β-sheet fibril structure. Overall, our work lays the foundation for using Raman spectroscopy in conjunction with MD simulations to determine detailed molecular-level structural models of amyloid fibrils in a manner that complements gold-standard techniques such as solid-state NMR and cryogenic electron microscopy. | Madeline Harper; Uma Nudurupati; Riley Workman; Taras Lakoba; Nicholas Perez; Delaney Nelson; Yangguang Ou; David Punihaole | Theoretical and Computational Chemistry; Physical Chemistry; Biological and Medicinal Chemistry; Biophysics; Biophysical Chemistry; Spectroscopy (Physical Chem.) | CC BY 4.0 | CHEMRXIV | 2023-09-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/650cbd0f60c37f4f763792ef/original/towards-determining-amyloid-fibril-structures-using-experimental-constraints-from-raman-spectroscopy.pdf |
62d4ec8c3787f18df1ba6801 | 10.26434/chemrxiv-2022-5hbl9 | Tunable Porosity and Conjugation in Ferrocene Polymers of Intrinsic Microporosity | Ferrocene (Fc) metallopolymers of intrinsic microporosity (MPIMs) have recently been reported as soluble, porous, non-network polymers, with evidence of electron delocalization along the polymer backbone. The combination of these properties makes Fc-MPIMs ideal candidate materials for optoelectronic devices, and the ability to tune these properties would broaden the impact of these materials. In this work, density functional theory (DFT) calculations at the CAM-B3LYP/def2SVP level were carried out on Fc MPIM fragments to examine the effect of pendant functional groups on conformational stability and electron delocalization in these systems. The conformational stability of the Fc MPIMs can affect the porosity, and the electronic delocalization is related to the conjugation in the material. The Fc MPIM fragments are most stable when the dihedral angle between Fc cyclopentadienyl (Cp) rings is 11.5°. Pendant functional groups are found to affect the stability of the local minimum at 144°, with alkyl chains increasing the stability, and bulky tert-butyl and trifluoromethyl groups decreasing stability. It is also possible to tune the electron delocalization of the HOMO and LUMO across the molecule. The Fe center of the Fc moiety contributes to the frontier orbitals, which is expected to enhance electronic communication in the parent polymer. Time-dependent density functional theory calculations indicate the π→π^* transition is slightly affected by the orientation of the dihedral angle between Cp rings, but primarily depends on the electronic nature of the pendant group. This work shows that the conformational stability and orbital delocalization of a model Fc MPIM can be tuned by functionalization with different pendant groups. | Theresa Chua; Liza Welch; Congyu Qian; Jeremy Feldblyum; Heidi Hendrickson | Theoretical and Computational Chemistry; Energy; Computational Chemistry and Modeling; Photovoltaics; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-07-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62d4ec8c3787f18df1ba6801/original/tunable-porosity-and-conjugation-in-ferrocene-polymers-of-intrinsic-microporosity.pdf |
60c7504f9abda267ebf8da20 | 10.26434/chemrxiv.13019747.v1 | N-Heterocyclic Carbene/Magnesium Co-catalyzed Radical Relay Assembly of Aliphatic Keto-nitriles | An N-heterocyclic carbene and
magnesium co-catalyzed three-component alkylacylation of alkenes with cycloketone
oxime esters and aldehydes was presented. This method displayed good scope
generality, providing a transition metal and photo-redox free pathway to access
various multi-functionalized aliphatic keto-nitrile structures under mild
reaction conditions. Moreover, this strategy is supposed to follow a radical
relay mechanism via a single electron transfer (SET) event of Mg/oxime
ester/Breslow intermediate ternary electron donating acceptor (EDA) complex. | Lei Chen; Shiyi Jin; Jian Gao; Tongtong Liu; Yuebo Shao; Jie Feng; Kangyi Wang; Tao Lu; Ding Du | Organocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2020-09-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7504f9abda267ebf8da20/original/n-heterocyclic-carbene-magnesium-co-catalyzed-radical-relay-assembly-of-aliphatic-keto-nitriles.pdf |
67da87f981d2151a02fa53a0 | 10.26434/chemrxiv-2025-02rvz | Atomic Orbits in Molecules and Materials for Improving Machine Learning Force Fields | The accurate representation of atoms within their environment forms the backbone of any reliable machine learning force field (MLFF). While modern MLFFs treat atoms of the same type as indistinguishable, their identities can be further resolved by accounting for the composition of their chemical environment. This can improve the parametrization of the MLFF model in chemically diverse systems. In this work, we introduce a novel, data-driven approach designed to find permutation symmetries in isolated and periodic systems, delivering key insights that enable the identification of atomic “orbits”, atoms that share consistent chemical and structural environments throughout the dataset. We demonstrate the effectiveness of the orbit representation by incorporating it into the kernel-based sGDML model and the equivariant message-passing neural network, MACE. For sGDML, trained on ethanol, 1,8-naphthyridine, D-alanine, and D-histidine adsorbed on graphene, we establish a strong correlation between force prediction accuracy and chemical diversity, quantified by orbit count. The results for the Ac-Phe-Ala5-Lys molecule further underscore the critical role of orbits in force reconstruction across various MLFF architectures. Incorporating orbits into MACE enables us to reduce the model size by an order of magnitude while preserving predictive accuracy, as demonstrated for the CsPbI$_3$ perovskite slab and graphene with a pyridinic-N defect. Overall, our approach provides a scalable and efficient solution for modeling complex chemical systems with state-of-the-art MLFFs. | Anton Charkin-Gorbulin; Artem Kokorin; Huziel E. Sauceda; Stefan Chmiela; Claudio Quarti; David Beljonne; Alexandre Tkatchenko; Igor Poltavsky | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Machine Learning | CC BY 4.0 | CHEMRXIV | 2025-03-20 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67da87f981d2151a02fa53a0/original/atomic-orbits-in-molecules-and-materials-for-improving-machine-learning-force-fields.pdf |
6773977a6dde43c908de853c | 10.26434/chemrxiv-2025-ft75g | Prediction of acute toxicity of organic contaminants to fish: model development and a novel approach to identify reactive substructures | In this study, count-based Morgan fingerprints (CMF) was used to represent the fundamental chemical structures of contaminants, and a neural network model (R²=0.76) was developed to predict acute fish toxicity (AFT) of organic compounds, which surpassed previous models. We found the limitations of in distinguishing homologous compounds may account for the suboptimal performance of binary fingerprints. The principles of generation and collision of CMF was explored and an improved method based on Tanimoto distance was introduced to calculated molecular similarity represented by CMFs as well. Toxic substructures identified by Shapley additive explanation (SHAP) method were substituted benzenes, long carbon chains, unsaturated carbons and halogen atoms. By incorporating KOW and monitoring shifts in feature importance, the influence of substructures on AFT was further delineated, revealing their roles in facilitating exposure and reactive toxicity. On this basis, we compared the toxicity of similar substructures and the same substructure in different chemical environments. To overcome the limitation of SHAP analysis, this study proposed a new method, toxicity index (TI), to identify substructures that were present in small quantities but highly toxic. With TI, we identified several important substructures, such as parathion and polycyclic substituents. We found that the toxicity of large substructures may be misestimated in the previous studies. | Li Shangyu; Zhang Mingming; Sun Peizhe | Earth, Space, and Environmental Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6773977a6dde43c908de853c/original/prediction-of-acute-toxicity-of-organic-contaminants-to-fish-model-development-and-a-novel-approach-to-identify-reactive-substructures.pdf |
66a8d1a201103d79c53a1782 | 10.26434/chemrxiv-2024-zf706 | Identifying Practical DFT Functional for Predicting 0D and 1D Organic Metal Halide Hybrids | Low dimensional organic metal halide hybrids (LD-OMHHs) have recently emerged as a new class of functional materials with various potential applications in optical, magnetic, and quantum information technologies. The high-throughput discovery and understanding of these materials necessitate identifying the best theoretical methods for generating reliable predictions of properties compared to experimental results. One of the key properties that has been studied is the band gap. This work systematically benchmarks several widely used density functional theory (DFT) functionals as well as the impact of spin-orbit coupling on band gap predictions for 115 experimentally reported LD-OMHHs. Surprisingly, it was found that the band gap predicted by GGA aligns similarly or better with experimentally measured values compared with two meta-GGA methods. Moreover, the inclusion of spin-orbital coupling has limited influence on band gap prediction. Such behavior can be understood by the potential existence of large excitonic effects in LD-OMHHs, which deviate computed fundamental gap from high-level DFT theory from experimental optical bandgap. Our research also reveals that the utilization of GGA functional without spin orbital coupling can be a practical and efficient method for the high-throughput screening of LD-OMMHs with reasonable band gaps. | Yufang He; Md Sazedul Islam; Jarek Viera; Hanwei Gao; Jianwei Sun; Biwu Ma; Bin Ouyang | Materials Science; Inorganic Chemistry; Transition Metal Complexes (Inorg.); Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-07-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66a8d1a201103d79c53a1782/original/identifying-practical-dft-functional-for-predicting-0d-and-1d-organic-metal-halide-hybrids.pdf |
60c74c970f50db3e1c396e93 | 10.26434/chemrxiv.12471263.v1 | Iron-Nickel Oxyhydroxide Catalyst from Watts Bath for the Oxygen Evolution Reaction in Water Electrolysis | A hydrogen economy is necessary to meet the social demands for less consumption of fossil fuels and it has several barriers that need to be addressed if this technology is to become cost effective. The oxygen evolution reaction (OER) is one of these barriers and catalysts based on nickel oxyhydroxide (NiOx) are believed to be promising for alkaline OER. We report results of iron doping for NiOx, we synthesized by electrodeposition, combinations of iron in Ni Watts solution to develop Fe- NiOx catalysts. The best sample has an overpotential of 254 mV at 10 mA cm-2 , this result is competitive to the best results found for alkaline OER. Our methodology consists of: linear and cyclic voltammetry, galvanostatic stability and electrochemical impedance spectroscopy as electrochemical techniques. In addition, physical catalyst characterization techniques include: scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, Raman spectroscopy and surface elemental analysis by wet chemistry.<br /> | Dario Delgado; Jan Bucher | Electrocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74c970f50db3e1c396e93/original/iron-nickel-oxyhydroxide-catalyst-from-watts-bath-for-the-oxygen-evolution-reaction-in-water-electrolysis.pdf |
64cba91edfabaf06ffa2f1bc | 10.26434/chemrxiv-2023-w1nc5 | Factorizing Yields in Buchwald-Hartwig Amination | The data collected in (1) are revisited and rigorously analyzed. We show that the matrix of descriptors used in the analysis of (1) is up to a linear transformation equivalent to a dummy coded matrix that reflects the design of the underlined experiment. Furthermore, it is argued that the reaction yield is better be modeled as a continuous Bernoulli random variable. Finally, a four-way ANOVA model with single replicates following a continuous Bernoulli distribution is fitted to the data under the assumption of the sparsity of the parameters, and estimated parameters are interpreted. Thereby, a novel regularisation technique based on the partial least squares algorithm is applied. | Tatyana Krivobokova; Gianluca Finocchio; Boris Maryasin | Theoretical and Computational Chemistry; Organic Chemistry; Machine Learning | CC BY NC ND 4.0 | CHEMRXIV | 2023-08-04 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64cba91edfabaf06ffa2f1bc/original/factorizing-yields-in-buchwald-hartwig-amination.pdf |
65ddef84e9ebbb4db9634ceb | 10.26434/chemrxiv-2024-lckq9-v3 | Preparation of tunable Cu-Ag nanostructures by electrodeposition in a deep eutectic solvent | The green transition requires the preparation of clean, inexpensive, and sustainable strategies to prepare controllable bimetallic and multimetallic nanostructures. Cu-Ag nanostructures, for example, are promising bimetallic catalysts for different electrocatalytic reactions such as carbon monoxide and carbon dioxide reduction. In this work, we present the one-step preparation method of electrodeposited Cu-Ag with tunable composition and morphology from choline chloride plus urea deep eutectic solvent (DES), a non-toxic and green DES. We have assessed how different electrodeposition parameters affect the morphology and composition of our nanostructures. We combine electrochemical methods with ex-situ scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) to characterize the nanostructures. We have estimated the electrochemically active surface area (ECSA) and roughness factor (R) by lead underpotential deposition (UPD). The copper/silver ratio in the electrodeposited nanostructures is highly sensitive to the applied potential, bath composition, and loading. We observed that silver-rich nanostructures were less adherent whereas the increase in copper content led to more stable and homogenous films with disperse rounded nanostructures with tiny spikes. These spikes were more stable when the deposition rate was fast enough and the molar ratio of Cu and Ag no greater than approximately two to one. | Elena Plaza-Mayoral; Kim Nicole Dalby; Hanne Falsig; Ib Chorkendorff; Paula Sebastian-Pascual; Maria Escudero-Escribano | Materials Science; Catalysis; Nanoscience; Nanocatalysis - Catalysts & Materials; Electrocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-02-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65ddef84e9ebbb4db9634ceb/original/preparation-of-tunable-cu-ag-nanostructures-by-electrodeposition-in-a-deep-eutectic-solvent.pdf |
62316bb121e2d02347a557dc | 10.26434/chemrxiv-2022-fthql | Second-Derivative-Based Background Drift Removal for Tonic Dopamine Measurement in Fast-Scan Cyclic Voltammetry | The dysregulation of dopamine, a neuromodulator, is associated with a broad spectrum of brain disorders, including Parkinson’s disease, addiction, and schizophrenia. Quantitative measurements of dopamine are essential for understanding dopamine functional dynamics. Fast-scan cyclic voltammetry (FSCV) is the most widely used electrochemical technique for measuring real-time in vivo dopamine level changes. Standard FSCV has only been used to analyze “phasic dopamine” (changes in seconds), because the gradual generation of background charging current is inevitable, and acts as the main noise source in the low-frequency band. Although “tonic dopamine” (changes in minutes to hours) is key for understanding the dopamine system, an electrochemical technique capable of simultaneously measuring phasic and tonic dopamine in an in vivo environment has not been established. Several modified voltammetric techniques have been developed for measuring tonic dopamine, but the sampling rates (0.1-0.05 Hz) are too low to be useful. Further investigation of the in vivo applicability of previously developed background drift removal methods for measuring tonic dopamine levels is required. We developed a second-derivative-based background removal (SDBR) method for simultaneously measuring phasic and tonic neurotransmitter levels in real-time. The performance of this technique was tested via in silico and in vitro tonic dopamine experiments. Furthermore, its applicability was tested in vivo. SDBR is a simple, robust, post-processing technique that can extract tonic neurotransmitter levels from all FSCV data. As SDBR is calculated in individual-scan voltammogram units, it can be applied to any real-time closed-loop system that uses a neurotransmitter as a biomarker. | Seongtak Kang; Jeongrak Park; Yunho Jeong; Yong-Seok Oh; Ji-Woong Choi | Theoretical and Computational Chemistry; Biological and Medicinal Chemistry; Analytical Chemistry; Biochemical Analysis; Electrochemical Analysis; Computational Chemistry and Modeling | CC BY NC 4.0 | CHEMRXIV | 2022-03-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62316bb121e2d02347a557dc/original/second-derivative-based-background-drift-removal-for-tonic-dopamine-measurement-in-fast-scan-cyclic-voltammetry.pdf |
672c91197be152b1d04f6ce5 | 10.26434/chemrxiv-2024-b10lj-v2 | How Charge Regulation Affects pH-Responsive Ampholyte Uptake in Weak Polyelectrolyte Brushes | Weak polyelectrolyte brushes are a promising platform for the selective capture and release of charged proteins from bulk solutions. Despite their potential for creating smart responsive surfaces, a detailed microscopic understanding of the uptake behavior in dependence of various parameters remains elusive. In this study, we employ coarse-grained, particle-based simulations to investigate how charge regulation under varying environmental conditions modulate the uptake and release of pH-responsive ampholytes, serving as a toy model for proteins, into weak polyelectrolyte brushes. For quenched brushes with constant ionization, the uptake of ampholytes remains strong across different isoelectric points. In contrast, for weak brushes, the ampholyte uptake becomes selectively sensitive to different isoelectric points and pKA-values and exhibits a non-monotonic behavior with changing pH. Enhanced proton partitioning into the brush lowers the local pH, significantly shifting the ionization states of both the brush (pKAapp > pKA) and ampholytes (pIapp > pI), such that the concurrent ionization of the brush and the ampholyte results in an optimum uptake strength for pKAapp < pH < pIapp. Adjusting the salt concentration broadens the uptake window and shifts the maximum uptake to higher pH values. Additionally, ampholytes with higher charge regulation capacitance near the isoelectric point demonstrate stronger adsorption, extending selective adsorption capabilities in ampholyte mixtures with similar isoelectric points. | Keerthi Radhakrishnan; David Beyer; Christian Holm | Theoretical and Computational Chemistry; Polymer Science | CC BY NC ND 4.0 | CHEMRXIV | 2024-11-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/672c91197be152b1d04f6ce5/original/how-charge-regulation-affects-p-h-responsive-ampholyte-uptake-in-weak-polyelectrolyte-brushes.pdf |
67859a8cfa469535b9ddeee7 | 10.26434/chemrxiv-2025-x8b23 | Shadow Molecular Dynamics with a Machine Learned Flexible Charge Potential | We present an extended Lagrangian shadow molecular dynamics scheme with an interatomic Born-Oppenheimer potential determined by the relaxed atomic charges of a second-order charge equilibration model. To parameterize the charge equilibration model, we use machine learning with neural networks to determine the environment-dependent electronegativities and chemical hardness parameters for each atom, in addition to the charge-independent energy and force terms. The approximate shadow molecular dynamics potential in combination with the extended Lagrangian formulation improves the numerical stability and reduces the number of Coulomb potential calculations required to evaluate accurate conservative forces. We demonstrate efficient and accurate simulations with excellent long-term stability of the molecular dynamics trajectories. The significance of the choosing fixed or environment-dependent electronegativities and chemical hardness parameters is evaluated. Finally, we compute the infrared spectrum of molecules via the dipole auto-correlation function and compare to experiments to highlight the accuracy of the shadow molecular dynamics scheme with a machine learned flexible charge potential. | Cheng-Han Li; Mehmet Cagri Kaymak; Maksim Kulichenko; Nicholas Lubbers; Benjamin Nebgen; Sergei Tretiak; Joshua Finkelstein; Daniel Tabor; Anders Niklasson | Theoretical and Computational Chemistry; Materials Science; Computational Chemistry and Modeling; Machine Learning | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67859a8cfa469535b9ddeee7/original/shadow-molecular-dynamics-with-a-machine-learned-flexible-charge-potential.pdf |
60c74ae50f50db4251396b40 | 10.26434/chemrxiv.12271289.v1 | Machine Learning for Accurate Force Calculations in Molecular Dynamics Simulations | <p>The computationally expensive nature of ab initio molecular dynamics simulations severely limits its ability to simulate large system sizes and long time scales, both of which are necessary to imitate experimental conditions. In this work, we explore an approach to make use of the data obtained using the quantum mechanical density functional theory (DFT) on small systems and use deep learning to subsequently simulate large systems by taking liquid argon as a test case. A suitable vector representation was chosen to represent the surrounding environment of each Ar atom, and a DNetFF machine learning model where, the neural network was trained to predict the difference in resultant forces obtained by DFT and classical force fields was introduced. Molecular dynamics simulations were then performed using forces from the neural network for various system sizes and time scales depending on the properties we calculated. A comparison of properties obtained from the classical force field and the neural network model was presented alongside available experimental data to validate the proposed method.</p> | Punyaslok Pattnaik; Shampa Raghunathan; Tarun Kalluri; Prabhakar Bhimalapuram; C. V. Jawahar; U. Deva Priyakumar | Computational Chemistry and Modeling; Theory - Computational; Machine Learning; Artificial Intelligence | CC BY NC ND 4.0 | CHEMRXIV | 2020-05-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74ae50f50db4251396b40/original/machine-learning-for-accurate-force-calculations-in-molecular-dynamics-simulations.pdf |
6136cec2b817b4409514b8a6 | 10.26434/chemrxiv-2021-dwghs | Activation of Cellulose with Alkaline Earth Metals | Alkaline earth metal ions accelerate the breaking of cellulose bonds and control the distribution of products in the pyrolysis of lignocellulose to biofuels and chemicals. Here, the activation of cellulose via magnesium ions was measured over a range of temperatures from 370 to 430 ⁰C for 20 to 2000 milliseconds and compared with activation of cellulose via calcium, another naturally-occurring alkaline earth metal in lignocellulose materials. The experimental approach of pulse heated analysis of solid/surface reactions (PHASR) showed that magnesium significantly catalyzes cellulose activation with a second order rate dependence on the catalyst concentration. An experimental barrier of 45.6 ± 2.1 kcal mol-1 and a pre-factor of 1.18 x 1016 (mmol Mg2+ / g CD)-2 * s-1 was obtained for the activation of α-cyclodextrin (CD), a cellulose surrogate, for catalyst concentrations of 0.1 to 0.5 mmol Mg+2 per gram of CD. First principles density functional theory calculations showed that magnesium ions play a dual role in catalyzing the reaction by breaking the hydrogen bonds with hydroxymethyl groups and destabilizing the reacting cellulose chain, thus making it more active. The calculated barrier of 47 kcal mol-1 is in agreement with the experimentally measured barriers and similar to that for calcium ion catalysts (~50 kcal mol-1). | Gregory Facas; Vineet Maliekkal; Matthew Neurock; Paul Dauenhauer | Catalysis; Chemical Engineering and Industrial Chemistry; Heterogeneous Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2021-09-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6136cec2b817b4409514b8a6/original/activation-of-cellulose-with-alkaline-earth-metals.pdf |
60c74c64f96a0005bd2877b7 | 10.26434/chemrxiv.12473174.v1 | Taming Troublesome Suzuki-Miyaura Reactions in Water Solution of Surfactants by the Use of Lecithin: A Step Beyond the Micellar Model | <div>The use of water solutions of industrial and designer surfactants enables performing a wide variety of chemical transformation on hydrophobic precursors. Mostly reactions </div><div>are clean, fast and efficient with vast benefits for overall sustainability. The widespread adoption of such methods is somewhat hampered by a lack of generality in the case of troublesome substrates and scaling up. The common literature solution for such issues is the use of small amounts of organic solvents. We here show that the use of a mixture of L-α-lecithin and Tween 80 is a preferable solution enabling the taming of particularly troublesome reactions, where even the cosolvent approach fails. The strong reduction of all interface tensions characterizing such complex multiphase systems is key to the results achieved. The protocol, applied to Suzuki-Miyaura couplings, allows to obtain complete reactions conversion at room temperature within one hour, is general and scalable from milligrams to up to 10 grams without further adjustments.</div> | Chiara Ceriani; Erika Ghiglietti; Mauro Sassi; Sara Mattiello; Luca Beverina | Organic Synthesis and Reactions; Process Chemistry; Heterogeneous Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2020-06-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74c64f96a0005bd2877b7/original/taming-troublesome-suzuki-miyaura-reactions-in-water-solution-of-surfactants-by-the-use-of-lecithin-a-step-beyond-the-micellar-model.pdf |
60c7550dbdbb895a9ea3a770 | 10.26434/chemrxiv.14034917.v1 | Strongly Bound Excitons in Metal-Organic Framework MOF-5: A Many-Body Perturbation Theory Study | During the past years, one of the most iconic metal-organic frameworks (MOFs), MOF-5, has been characterized as a semiconductor by theory and experiments. Here we employ the GW many-body perturbation theory in conjunction with the Bethe-Salpeter equation (BSE) to compute the electronic structure and optical properties of this MOF. The GW calculations show that MOF-5 is a wide band-gap insulator with a fundamental gap of ∼ 8 eV. The strong excitonic effects, arising from highly localized states and low screening, result in an optical gap of 4.5 eV and in an optical absorption spectrum in excellent agreement with experiments. The origin of the incorrect conclusion reported by past studies and the implication of this result are also discussed. | Aseem Rajan Kshirsagar; Xavier Blase; Claudio Attaccalite; Roberta Poloni | Hybrid Organic-Inorganic Materials; Computational Chemistry and Modeling; Theory - Computational; Physical and Chemical Properties; Quasiparticles and Excitations; Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2021-02-16 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7550dbdbb895a9ea3a770/original/strongly-bound-excitons-in-metal-organic-framework-mof-5-a-many-body-perturbation-theory-study.pdf |
63ebabaefcfb27a31fc7a64a | 10.26434/chemrxiv-2023-1vw27-v2 | Topology-Controlled Self-Assembly of Amphiphilic Block Copolymers | Contemporary synthetic chemistry approaches can be used to yield a range of distinct polymer topologies with precise control. The topology of a polymer strongly influences its self-assembly into complex nanostructures however a clear mechanistic understanding of the relationship between polymer topology and self-assembly has not yet been developed. In this work, we use atomistic molecular dynamics simulations to provide a nanoscale picture of the self-assembly of three poly(ethylene oxide)-poly(methyl acrylate) block copolymers with different topologies into micelles. We find that the topology affects the ability of the micelle to form a compact hydrophobic core, which directly affects its stability. Also, we apply unsupervised machine learning techniques to show that the topology of a polymer affects its ability to take a conformation in response to the local environment within the micelles. This work provides foundations for the rational design of polymer nanostructures based on their underlying topology. | Raquel Lopez-Rios De Castro; Robert Ziolek; Chris Lorenz | Theoretical and Computational Chemistry; Physical Chemistry; Polymer Science; Polymer morphology; Computational Chemistry and Modeling; Self-Assembly | CC BY 4.0 | CHEMRXIV | 2023-02-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63ebabaefcfb27a31fc7a64a/original/topology-controlled-self-assembly-of-amphiphilic-block-copolymers.pdf |
60c74373469df41629f431a0 | 10.26434/chemrxiv.7051895.v2 | Measuring Reaction Rate Constant in Individual Cells to Facilitate Accurate Analysis of Cell-Population Heterogeneity | We propose Cytometry of Reaction Rate Constant (CRRC) for accurate analysis of cell-population heterogeneity with respect to a specific molecular reaction. Conceptually, in CRRC, the cells are loaded with a reaction substrate, and its conversion into a product is followed by time-lapse fluorescence microscopy at the single-cell level. A reaction rate constant is determined for every cell by using a known kinetic mechanism of the reaction, and a kinetic histogram “number of cells vs. the rate constant” is built. Finally, this histogram is used to determine parameters of reaction-based cell-population heterogeneity. Here, we studied a reaction of substrate extrusion from cells by ABC transporters. We proved that sizes of subpopulations with different extrusion rates could be accurately determined from the kinetic histogram, and this determination was not significantly affected by change in substrate concentration. We foresee that CRRC will facilitate the development of reliable disease biomarkers based on parameters of reaction-based cell-population heterogeneity. | Vasilij Koshkin; Sven Kochmann; Apinaya Sorupanathan; Chun Peng; Laurie E. Ailles; Geoffrey Liu; Sergey N. Krylov | Biochemical Analysis; Bioinformatics and Computational Biology; Cell and Molecular Biology; Chemical Kinetics | CC BY NC ND 4.0 | CHEMRXIV | 2019-07-22 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74373469df41629f431a0/original/measuring-reaction-rate-constant-in-individual-cells-to-facilitate-accurate-analysis-of-cell-population-heterogeneity.pdf |
625bd521ed4d88c3770df67e | 10.26434/chemrxiv-2022-4b442-v2 | Emerging chemical heterogeneities in a commercial 18650 Li-ion battery during early cycling | Synchrotron X-ray diffraction computed tomography (XRD-CT) was employed to study a commercial 18650 cylindrical LiNi0.8Co0.15Al0.5O2 (NCA) battery under operating conditions and during seven cycles. Multiple chemical heterogeneities related to the lithium distribution were observed in both the cathode and the anode from the analysis of the spatially-resolved diffraction signals. It is shown that during the battery charging, the anode exhibits different degrees of activity regarding the lithiation process. Explicitly, the following three regions were identified: uniform/homogenous lithiation, delayed lithiation and inactive-to-lithiation regions. The inactive-to-lithiation anode region was a result of the specific cell geometry (i.e. due to lack of cathode tape opposite these anode areas) and throughout the cycling experiments remained present in the form of LiC30-30+. The delayed lithiation region was seen to have a direct impact on the properties of NCA in its close proximity during the battery discharging, preventing its full lithiation. Further to this, the aluminum tab negatively affected the NCA in direct contact with it, leading to different lattice parameter a and c evolution compared to the rest of the cathode. | Dorota Matras; Thomas E. Ashton; Hongyang Dong; Marta Mirolo; Isaac Martens; Jakub Drnec; Jawwad A. Darr; Paul D. Quinn; Simon D.M. Jacques; Andrew M. Beale; Antonis Vamvakeros | Materials Science; Inorganic Chemistry; Energy; Solid State Chemistry; Energy Storage; Crystallography – Inorganic | CC BY 4.0 | CHEMRXIV | 2022-04-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/625bd521ed4d88c3770df67e/original/emerging-chemical-heterogeneities-in-a-commercial-18650-li-ion-battery-during-early-cycling.pdf |
65ae6571e9ebbb4db9b90421 | 10.26434/chemrxiv-2024-z6rss | Nickel Catalyzed C–S Cross Coupling of Sterically Hindered Aryl Triflates with Alkyl Thiols | Due to the smaller size of nickel compared to palladium, the C–S cross-coupling of sterically challenging aryl electrophiles with alkyl thiols under nickel catalysis remained elusive. Herein, we report the nickel-catalyzed cross-coupling of alkyl thiols with aryl triflates bearing functional groups in ortho-position relative to the leaving group using Ni(cod)2/DPEphos (L1) or dppbz (L2) as the catalytic system. For substrates featuring non-coordinating ortho-substituents, the reaction operates under mild conditions using L1, while for electrophiles bearing coordinating groups, the ligand L2 and elevated temperatures are required. The synthetic utility could be demonstrated on numerous examples, including biologically relevant compounds, and on larger scale. Instead of Ni(cod)2, more cost-efficient Ni(OAc)2 can also be employed in the presence of zinc as reductant. Furthermore, insights into the reaction mechanism were obtained by competition experiments, isolation of organometallic intermediates and computations. | Ivo Lindenmaier; Robert Richter; Ivana Fleischer | Organic Chemistry; Catalysis; Organic Synthesis and Reactions; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-01-23 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65ae6571e9ebbb4db9b90421/original/nickel-catalyzed-c-s-cross-coupling-of-sterically-hindered-aryl-triflates-with-alkyl-thiols.pdf |
618d053c64238040c1cf0ae1 | 10.26434/chemrxiv-2021-5rsr2 | Multiscale modeling of bio-nano interactions of zero-valent silver nanoparticles. | Understanding the specifics of interaction between protein and nanomaterial is crucial for designing efficient, safe, and selective nanoplatforms, such as biosensor or nanocarrier systems. Routing experimental screening for the most suitable complementary pair of biomolecule and nanomaterial used in such nanoplatforms might be a resource-intensive task. While a variety of computational tools is available for pre-screening libraries of small drug molecules interacting with proteins, options for high-throughput screening of protein libraries for binding affinities to new and existing nanomaterials are limited. In the current work, we present the results of a systematic computational study of protein interaction with zero-valent silver nanoparticles using a multiscale approach. A variety of blood plasma and dietary proteins, namely, bovine and human serum albumins, bovine and human hemoglobin, papain, bromelain, lysozyme, and bovine lactoferrin, were examined. Selected combinations of nanomaterial and proteins can serve as a starting model for developing noble metal-based nanocarriers and biosensors. The computed binding (adsorption) characteristics for selected proteins were validated by experimental data reported in the literature. An advanced in silico nano-QSAR/QSPR interfacial descriptor 〖logP〗^NM was also introduced to characterize the relative hydrophobicity/hydrophilicity of the nanomaterial. | Julia Subbotina; Vladimir Lobaskin | Theoretical and Computational Chemistry; Physical Chemistry; Nanoscience; Computational Chemistry and Modeling; Chemoinformatics - Computational Chemistry; Interfaces | CC BY NC ND 4.0 | CHEMRXIV | 2021-11-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/618d053c64238040c1cf0ae1/original/multiscale-modeling-of-bio-nano-interactions-of-zero-valent-silver-nanoparticles.pdf |
612dd56c65db1edee8a8bf21 | 10.26434/chemrxiv-2021-0w5zj | Can Electric Field be a Descriptor of Catalytic Activity? A Case Study on Chorismate Mutase | The current theoretical perception of enzymatic activity is highly reliant on the determination of activation energy of the reactions which is often calculated using a computational demanding quantum mechanical calculation. With the ever-increasing use of bioengineering techniques that produce too many variants of the same enzyme, a fast and accurate way to study the relative
efficiency of enzymes is a need of time. Here, we propose the electric field (EF) of the enzyme along the reaction axis as a descriptor for the enzymatic activity using an example of Chorismate Mutase in its native and several variants (R90A, R90G, and R90K/C88S). The study shows a linear
correlation between the calculated enzymatic EF and enzymatic activity of all complexes. The MD simulations of the Michaelis complex and the transition state analog (TSA) show a stabilizing force on TSA due to the enzymatic EF. The QM/MM and QM-only DFT calculations with the presence of External Electric Field (EEF) oriented along the reaction axis show that the electric can increase the dipole moment of the TS, thereby, stabilizing it and thus lowers the activation energy. | Shakir Ali Siddqui; Kshatresh Dubey | Theoretical and Computational Chemistry; Physical Chemistry; Catalysis; Computational Chemistry and Modeling; Theory - Computational; Physical and Chemical Properties | CC BY 4.0 | CHEMRXIV | 2021-09-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/612dd56c65db1edee8a8bf21/original/can-electric-field-be-a-descriptor-of-catalytic-activity-a-case-study-on-chorismate-mutase.pdf |
65ce3e75e9ebbb4db96e913b | 10.26434/chemrxiv-2024-24nj1 | Electrocatalytic Reduction of Disulfide Bonds in Antibodies | In most FDA-approved antibody-drug conjugates, cysteines generated through reduction of the native interchain di-sulfide bonds in monoclonal antibodies (mAbs) are conjugated with maleimide-based cytotoxic payloads. Despite being key to efficiently producing well-defined conjugates, selective disulfide reduction strategies are severely underdevel-oped. Herein, we report a vitamin B12-catalyzed, electrochemically driven protocol that efficiently reduces disulfide bonds in various aqueous buffers and at a broad pH range. This robust and simple method is suitable for disulfide reduc-tions of substrates ranging from biologically relevant small molecules to large proteins. Finally, one-pot reduc-tion/conjugation of disulfide bonds in mAbs was achieved to access antibody conjugates. | Serge Ruccolo; Marion, H. Emmert; Cecilia Bottecchia; Yangzhong Qin; Rodell Barrientos; Kelly Raymond; Monica Haley | Biological and Medicinal Chemistry; Organic Chemistry; Catalysis; Process Chemistry; Bioengineering and Biotechnology; Electrocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2024-02-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65ce3e75e9ebbb4db96e913b/original/electrocatalytic-reduction-of-disulfide-bonds-in-antibodies.pdf |
62911a37d50418fa82c594c9 | 10.26434/chemrxiv-2021-qjxgd-v2 | Ultrafast and Selective Labeling of Endogenous Proteins Using Affinity-based Benzotriazole Chemistry | Chemical modification of proteins is enormously useful for characterizing protein function in complex biological systems and for drug development. Selective labeling of native or endogenous proteins is challenging owing to the existence of distinct functional groups in proteins and in living systems. Chemistry for rapid and selective labeling of proteins remains in high demand. Here we have developed novel affinity labeling probes using benzotriazole (BTA) chemistry. We showed that affinity-based BTA probes selectively and covalently label a lysine residue in the vicinity of the ligand binding site of a target protein with a reaction half-time of 28 s. The reaction rate constant is comparable to the fastest biorthogonal chemistry. This approach was used to selectively label different cytosolic and membrane proteins in vitro and in live cells. BTA chemistry could be widely useful for labeling of native/endogenous proteins, target identification and development of covalent inhibitors. | Xiaoyi Xin; Yu Zhang; Massimiliano Gaetani; Susanna Lundström; Roman Zubarev; Yuan Zhou; Dale Corkery; Yaowen Wu | Biological and Medicinal Chemistry; Organic Chemistry; Bioorganic Chemistry; Chemical Biology | CC BY NC ND 4.0 | CHEMRXIV | 2022-06-01 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62911a37d50418fa82c594c9/original/ultrafast-and-selective-labeling-of-endogenous-proteins-using-affinity-based-benzotriazole-chemistry.pdf |
60c749f9469df40480f43c69 | 10.26434/chemrxiv.9992369.v2 | The Conserved Positive Charge in the Transmembrane Domain of HIV Gp41 Contributes to Its Intrinsic Preference for Trimerization | The transmembrane (TM) domain of HIV glycoprotein gp41 anchors the envelope (Env) spike in the viral membrane and is highly conserved. The mid-span arginine 696 is particularly conserved, and the only other residue found in this position is lysine. Seeking to examine the role of this conserved positive charge in the structure and function of the gp41 TM domain, we synthesized a series of peptides corresponding to this region. Analysis of the peptides in a previously validated fluorescence assay in model membranes showed that the native TM domain is trimeric. Peptides in which the intramembrane arginine was mutated to alanine showed significantly lower trimerization propensity. In contrast, this mutation in the context of infectious pseudovirus caused only modest decreases in viral stability and infectivity. We propose a model to explain the importance of this charge to gp41 structure and to HIV infection. | Timothy Reichart; Daniel Leaman; Daniel Sands; Michael Zwick; Philip Dawson | Biochemistry | CC BY NC ND 4.0 | CHEMRXIV | 2020-04-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c749f9469df40480f43c69/original/the-conserved-positive-charge-in-the-transmembrane-domain-of-hiv-gp41-contributes-to-its-intrinsic-preference-for-trimerization.pdf |
629f4a16bb7519e246459c2e | 10.26434/chemrxiv-2022-zkqsz | Ultrafast Metal Oxide Reduction at Pd/PdO2 Interface Enables One-Second Hydrogen Gas Detection Under Ambient Conditions | Here, we report a Pd/PdOx sensing material that achieves 1-s detection of 4% H2 gas (i.e., the lower explosive limit concentration for H2) at room temperature in air. The Pd/PdOx material is a network of interconnected nanoscopic domains of Pd, PdO, and PdO2. Upon exposure to 4% H2, PdO and PdO2 in the Pd/PdOx can be immediately reduced to metallic Pd, generating over a >90% drop in electrical resistance. The mechanistic study reveals that the Pd/PdO2 interface in Pd/PdOx is responsible for the ultrafast PdOx reduction. Metallic Pd at the Pd/PdO2 interface enables fast H2 dissociation to adsorbed H atoms, which is otherwise the rate-determining step on PdO2, significantly lowering the PdO2 reduction barrier. In addition, the interconnectivity of Pd, PdO, and PdO2 in Pd/PdOx facilitates the reduction of PdO. The 1-s response time of Pd/PdOx under ambient conditions makes it an excellent alarm for the timely detection of hydrogen gas leaks. | Xin Geng; Shuwei Li; Zhi Mei; Dongsheng Li; Liang Zhang; Long Luo | Analytical Chemistry; Nanoscience; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-06-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/629f4a16bb7519e246459c2e/original/ultrafast-metal-oxide-reduction-at-pd-pd-o2-interface-enables-one-second-hydrogen-gas-detection-under-ambient-conditions.pdf |
65214fd78bab5d2055d4266f | 10.26434/chemrxiv-2023-4s6km | Rapid, High-Capacity Adsorption of Iodine from Aqueous Environments with Amide Functionalized Covalent Organic Frameworks | The uses and production of radionuclides in nuclear energy production and medical therapy are becoming more significant in today’s world. While these applications have many benefits, they can produce harmful pollutants, such as radioactive iodine, that need to be sequestered. Effective capture and storage of radioactive iodine waste remains a major challenge for nuclear energy generation and nuclear medicine. Here we report the highly efficient capture of iodine in a series of mesoporous, two-dimensional (2D) covalent organic frameworks, called COFamides, which contain amide sidechains in their pores. COFamides are capable of rapidly removing iodine from aqueous solutions at concentrations as low as 50 ppm, with total capacities greater than 650 wt%. In order to explain the high affinity of the COFamide series for iodine and iodide species in water, we performed a computational analysis of the interactions the COFamide framework and iodine guests. These studies suggest that the origin of the large iodine capacity in these materials can be explained by the presence of multiple, cooperative, non-covalent interactions between the framework and both iodine, and iodide species. | Niyati Arora; Tanay Debnath; Milinda Senarathna; Isabella Roske; Andres Cisneros; Ronald Smaldone | Theoretical and Computational Chemistry; Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2023-10-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65214fd78bab5d2055d4266f/original/rapid-high-capacity-adsorption-of-iodine-from-aqueous-environments-with-amide-functionalized-covalent-organic-frameworks.pdf |
60c747489abda285d0f8c8a4 | 10.26434/chemrxiv.11365136.v1 | Insights into the Carbon Balance for CO2 Electroreduction on Cu using Gas Diffusion Electrode Reactor Designs | In this work, the carbon balance during high-rate CO2 reduction in flow electrolyzers is rigorously analyzed. The CO2 consumption at gas-diffusion electrodes due to electrochemical reduction and reaction with OH- at the electrode-electrolyte interface leads to a substantial reduction in the volumetric flowrate of gas flow out of the electrolyzer, especially when highly alkaline electrolytes and elevated current densities are utilized, mainly owing to elevated pH at cathode/electrolyte interface. Without considering the CO2 consumption, the Faradaic efficiencies for major gas products could be significantly overestimated during high current density CO2 reduction conditions, particularly in the case of high pH electrolyte. In addition, a detailed carbon balance path is elucidated via a two-step procedure of CO2 reaction with OH- at cathode/electrolyte interface and subsequent CO2 generation at anode/electrolyte interface caused by a relatively low pH in the vicinity of the anode. Based on the proposed two-step carbon balance path, a systemic exploration of gases released in anolyte reveals the transformation of a HCO3- or OH- catholyte to a CO32- catholyte, which was further confirmed by pH measurement. | Ming Ma; Ezra Lee Clark; Kasper T. Therkildsen; Sebastian Dalsgaard; Ib Chorkendorff; Brian Seger | Electrocatalysis; Energy Storage; Fuels - Energy Science | CC BY NC ND 4.0 | CHEMRXIV | 2020-01-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c747489abda285d0f8c8a4/original/insights-into-the-carbon-balance-for-co2-electroreduction-on-cu-using-gas-diffusion-electrode-reactor-designs.pdf |
63fc672932cd591f128aa8d1 | 10.26434/chemrxiv-2023-sxp2x | Rhenium Biscorrole Sandwich Compounds: XAS Evidence for A New Coordination Motif | Interaction of three free-base meso-tris(p-X-phenyl)corroles H3[TpXPC] (X = H, CH3, OCH3) with Re2(CO)10 at 235 C in the presence of K2CO3 in o-dichlorobenzene has led to putative rhenium biscorrole sandwich compounds with the formula ReH[TpXPC]2. DFT calculations and Re L3 EXAFS measurements suggest a seven-coordinate metal center, with the extra hydrogen located on one of the corrole nitrogens. The complexes can be deprotonated by a base such as DBU, resulting in substantial sharpening of UV-visible spectra and split Soret bands, consistent with the generation of C2-symmetric anions. Both the seven-coordinate neutral and the eight-coordinate anionic forms of the complexes represent a new coordination motif in the field of Re-porphyrinoid interactions. | Abraham Alemayehu; Macon Abernathy; Jeanet Conradie; Ritimukta Sarangi; Abhik Ghosh | Theoretical and Computational Chemistry; Inorganic Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-02-27 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63fc672932cd591f128aa8d1/original/rhenium-biscorrole-sandwich-compounds-xas-evidence-for-a-new-coordination-motif.pdf |
633dacb72984c968977925af | 10.26434/chemrxiv-2022-crzh7 | Radical-like reactivity for dihydrogen activation by coinage metal-aluminyl complexes: computational evidence inspired by experimental main group chemistry | The computational study of an unprecedented reactivity of coinage metal-aluminyl complexes with dihydrogen is reported. In close resemblance to Group 14 dimetallenes and dimetallynes, the complexes are predicted to activate H2 under mild conditions. Two different reaction pathways are found disclosing a common driving force, i.e., the nucleophilic behavior of the electron-sharing M-Al (M = Cu, Ag, Au) bond, which enables a cooperative and diradical-like mechanism. This mode of chemical reactivity emerges as a new paradigm for dihydrogen activation and calls for an experimental feedback. | Diego Sorbelli; Leonardo Belpassi; Paola Belanzoni | Theoretical and Computational Chemistry; Inorganic Chemistry; Catalysis; Bonding; Coordination Chemistry (Inorg.); Small Molecule Activation (Inorg.) | CC BY NC ND 4.0 | CHEMRXIV | 2022-10-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/633dacb72984c968977925af/original/radical-like-reactivity-for-dihydrogen-activation-by-coinage-metal-aluminyl-complexes-computational-evidence-inspired-by-experimental-main-group-chemistry.pdf |
6250ed9611b1466f8d1ceb8b | 10.26434/chemrxiv-2022-6lcng | A novel application of generation model in foreseeing ‘future’ reactions | Deep learning is widely used in chemistry and can rival human chemists in certain scenarios. Inspired by molecule generation in new drug discovery, we present a deep learning-based reaction generation approach to perform reaction generation with the Trans-VAE model in this study. To comprehend how exploratory and innovative the model is in reaction generation, we constructed the dataset by time-split. We applied the Michael addition reaction as the generation vehicle and took the reactions reported before a certain date as the training set and explored whether the model could generate reactions that were reported after the date. We took 2010 and 2015 as the time points for the splitting of the Michael addition reaction respectively. Among the generated reactions, 911 and 487 reactions were applied in the experiments after the respective split time points, accounting for 12.75% and 16.29% of all reported reactions after each time point. The generated results were in line with expectations and additionally generated a large quantity of new chemically feasible Michael addition reactions, which also demonstrated the learnability of the Trans-VAE model for reaction rules. Our research provides a reference for future novel reaction discovery using deep learning. | Hongliang Duan; Liefeng Ma; Lujing Cao; Yejian Wu; Zhajun Zhan | Organic Chemistry; Organic Synthesis and Reactions | CC BY NC ND 4.0 | CHEMRXIV | 2022-05-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6250ed9611b1466f8d1ceb8b/original/a-novel-application-of-generation-model-in-foreseeing-future-reactions.pdf |
60c7524f9abda23163f8ddc5 | 10.26434/chemrxiv.13281182.v1 | Photoelectrocatalytic Cross-Dehydrogenative Coupling of Unactivated Aliphatic Hydrogen Donors with Benzothiazoles: Synthetic Applications and Mechanistic Insights | We report herein a photoelectrocatalytic strategy for the smooth preparation of 2-alkylbenzothiazoles via the cross-dehydrogenative coupling of unactivated aliphatic hydrogen donors (e.g. alkanes) with benzothiazoles. We used tetrabutylammonium decatungstate (TBADT) as the photocatalyst to cleave the strong C(sp3)-H bonds embedded in the chosen substrates via Hydrogen Atom Transfer (HAT), while electrochemistry ensured the success of this net-oxidative transformation by scavenging the extra electrons. The reaction progress was monitored through kinetic analysis, highlighting the transient formation of the redox-neutral adduct 2-alkylbenzothiazoline. Further cyclic voltammetry and laser flash photolysis experiments unveiled the chameleonic behavior of TBADT that features a three-fold role: HAT photocatalyst to activate alkanes, photoredox catalyst to activate the 2-alkylbenzothiazoline and electrocatalyst to promote the oxidation of short-lived radical intermediates. The adopted potentiostatic mode allowed to tame the multi-faceted reactivity of TBADT and to ensure its recovery after each catalytic cycle with a very high faradaic efficiency. We proved the versatility of the proposed approach by replacing the potentiostat with a couple of cheap batteries in the preparation of the desired products.<br /> | Luca Capaldo; Lorenzo L. Quadri; Daniele Merli; Davide Ravelli | Organic Synthesis and Reactions; Electrocatalysis; Photocatalysis | CC BY NC ND 4.0 | CHEMRXIV | 2020-11-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7524f9abda23163f8ddc5/original/photoelectrocatalytic-cross-dehydrogenative-coupling-of-unactivated-aliphatic-hydrogen-donors-with-benzothiazoles-synthetic-applications-and-mechanistic-insights.pdf |
64d7af964a3f7d0c0d0eebd6 | 10.26434/chemrxiv-2023-c46mv | pHbot: Self-Driven Robot for pH Adjustment of Viscous Formulations via Physics-informed-ML | pH adjustment is crucial for many industrial products, yet this step is typically performed by manual trial-and-error. A particularly industrially relevant yet challenging titration is that of adjusting viscous liquid formulations using weak, polyprotic titrants (usually citric acid). Handling of viscous, non-Newtonian formulations, with such polyprotic acids preferred for their chelation and buffering effects make a robotic solution challenging. We present a self-driving pH robot integrated with physics-informed learning; this hybrid physical-ML model enables automated titration with weak-strong acid/base pairs. To deal with the high viscosities of these formulations, we developed specific automated mixing and cleaning protocols. We hit the target pH within two to five iterations over 250 distinct formulations in labscale small-batch (~ 10 mL and 12 samples) titrations. In the interest of scaling up to match industrial processes, we also demonstrate that our hybrid algorithm works at ~25x scale-up. The method is general, and we open-source our algorithm and designs. | Aniket Chitre; Jayce Cheng; Sarfaraz Ahmed; Robert Querimit; Kedar Hippalgaonkar; Alexei Lapkin | Chemical Engineering and Industrial Chemistry; Industrial Manufacturing | CC BY 4.0 | CHEMRXIV | 2023-08-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64d7af964a3f7d0c0d0eebd6/original/p-hbot-self-driven-robot-for-p-h-adjustment-of-viscous-formulations-via-physics-informed-ml.pdf |
65606f345bc9fcb5c9443dec | 10.26434/chemrxiv-2023-m29g4 | Interfacial Mechanics of b-Casein and Albumin Mixed Protein Assemblies at Liquid-Liquid Interfaces | Protein emulsifiers play an important role in formulation science, from food product development to emerging applications in biotechnologies. The impact of mixed protein assemblies on surface composition and interfacial shear mechanics remains broadly unexplored, in comparison to the impact that formulation has on dilatational mechanics and surface tension or pressure. In this report, we use interfacial shear rheology to quantify the evolution of interfacial shear moduli as a function of composition in bovine serum albumin (BSA)/b-casein mixed assemblies. We present the striking difference in mechanics of these two protein and observe the dominance of -casein in regulating interfacial shear mechanics. This observation correlates well with the strong asymmetry of adsorption of these two proteins, characterised by fluorescence microscopy. Using neutron reflectometry and fluorescence recovery after photobleaching, we examine the architecture of corresponding protein assemblies and their surface diffusion, providing evidence for distinct morphologies, but surprisingly comparable diffusion profiles. Finally, we explore the impact of crosslinking and sequential protein adsorption on the interfacial shear mechanics of corresponding assemblies. Overall, this work indicates that, despite comparable surface densities, BSA and b-casein assemblies at liquid-liquid interfaces display almost 2 orders of magnitude difference in interfacial shear storage modulus and strikingly different viscoelastic profiles. In addition, co-adsorption and sequential adsorption processes are found to further modulate interfacial shear mechanics. Beyond formulation science, the understanding of complex mixed protein assemblies and mechanics may have implications for the stability of emulsions and may underpin changes in the mechanical strength of corresponding interfaces, for example in tissue culture or physiological conditions. | Alexandra Chrysanthou; Minerva Bosch-Fortea; Ali Zarbakhsh; Julien Gautrot | Materials Science; Chemical Engineering and Industrial Chemistry; Agriculture and Food Chemistry; Aggregates and Assemblies; Surfactants; Thin Films | CC BY 4.0 | CHEMRXIV | 2023-11-24 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65606f345bc9fcb5c9443dec/original/interfacial-mechanics-of-b-casein-and-albumin-mixed-protein-assemblies-at-liquid-liquid-interfaces.pdf |
61fb7d81c86ae2564f145f41 | 10.26434/chemrxiv-2022-6q4xb | Non-Resonant Probing of the Methyl Fragment at 213 nm following 266nm Photolysis of Methyl Iodide | The velocity map imaging of the methyl radical formed by 266 nm photolysis of methyl iodide using 213 nm non-resonant multi-photon ionization (NRMPI) method. Comparison of the NRMPI method with the well-known (2+1) resonance multi-photon ionization (REMPI) method at 333.45 nm, which selectively probes Q-branch of band-origin transition of the methyl radical, indicates that the NRMPI method yields a significantly higher I/I* branching ratio in comparison to the REMPI method, even though the velocity map images of both the methods are qualitatively similar. The higher I/I* branching ratio obtained in the NRMPI method is attributed to the non-resonant ionization of higher quanta states of the umbrella bending mode along with higher rotational states of the methyl fragment in the CH3+I dissociation channel. Thus, results obtained in the present work signify that a 213 nm excitation source, which is easily available as the fifth harmonic of Nd:YAG laser, can be used as an alternative and efficient probe to investigate photo-dissociation dynamics of polyatomic molecules. | Monali Kawade; Sumitra Singh; G Naresh Patwari | Physical Chemistry; Photochemistry (Physical Chem.); Spectroscopy (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2022-02-03 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61fb7d81c86ae2564f145f41/original/non-resonant-probing-of-the-methyl-fragment-at-213-nm-following-266nm-photolysis-of-methyl-iodide.pdf |
66c5c1eba4e53c48761a425b | 10.26434/chemrxiv-2024-nj473 | Advancing SilverSil sol-gel chemistry towards practical application | Showing significant antimicrobial activity (in vitro), SilverSil is the name of sol-gel coatings consisting of organically modified silica (ORMOSIL) entrapping silver nanoparticles originally derived from methyltriethoxysilane (MTES) and tetraethylorthosilicate (TEOS) only. In this study, we report the outcomes of investigation aimed at developing SilverSil coatings in sight of practical application. Besides MTES, we investigate the use of 3-(aminopropyl)trimethoxysilane (APTMS) to prepare new SilverSil coatings. The effect of selected parameters including the water/alkoxide ratio, the presence of ethanol as a co-solvent, the time of gel aging, the gel drying conditions, and the presence of AgNO3 were investigated. Results are revealing and further support the investigation of SilverSil towards practical application as antibacterial coatings of broad scope and limited antimicrobial resistance. | Giovanna Li Petri; Rosaria Ciriminna; Mario Pagliaro | Materials Chemistry | CC BY NC 4.0 | CHEMRXIV | 2024-08-21 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66c5c1eba4e53c48761a425b/original/advancing-silver-sil-sol-gel-chemistry-towards-practical-application.pdf |
611cf1a6ac8b499b36458d19 | 10.26434/chemrxiv-2021-x5sj7 | National Institutes of Health (NIH) Workshop on Reaction Informatics | The virtual workshop took place on May 18-20, 2021. It was a follow-up from the December 2020 NIH Workshop on Ultra Large Chemistry Databases. A major theme emerging from the December 2020 workshop was the fact that all the databases of a billion or more structures are virtual. For each virtual molecule the question then arises of whether, or how, it can be synthesized. The organizers therefore assembled speakers to give presentations about how reaction-related data are represented, captured, managed in databases, analyzed, used for drug design, applied in robotics, and exchanged locally as well as globally. This report summarizes talks from 27 practitioners in the reaction informatics field. The aim is to represent as accurately as possible the information that was delivered by the speakers; the report does not seek to be evaluative. The themes, in the order used for this report, were reaction representations, file formats, and standards; sources of reaction data; AI and machine learning applications of reaction-related data in de novo drug design, synthetic accessibility, synthesis planning, reaction prediction etc.; and automation and progression toward autonomous synthesis. | Wendy Warr | Theoretical and Computational Chemistry; Machine Learning; Artificial Intelligence; Chemoinformatics - Computational Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2021-08-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/611cf1a6ac8b499b36458d19/original/national-institutes-of-health-nih-workshop-on-reaction-informatics.pdf |
6441f2b9e4bbbe4bbffc7d20 | 10.26434/chemrxiv-2023-55c68 | Recital Vector Dot Operations for Chemistry Students | I have been teaching physical chemistry to undergraduate students for several years now. I have observed that my interpretation of vector-matrix calculations and complex calculations has not been well received by the chemistry students. The traditional vector notation of adding an arrow on top of a variable and the matrix format work for students with vector and matrix-associated training backgrounds but are not well received by the students who have not seen it before.1 We have been using vector square calculations in these classes in many places. Thus, there is a need to introduce vector calculations, especially square vector calculations to these students. I have recommended the students watch outstanding YouTube channels such as 3Blue1Brown that visualize vector calculations. I am proposing here to introduce a form more like linear algebra that is more familiar to the students and focuses on the DOT operations of the vectors to these undergraduate students. Linearized vector notations have been widely used in almost all computer coding languages and have been proven to be efficient by many coders. | Jixin Chen | Chemical Education; Chemical Education - General | CC BY 4.0 | CHEMRXIV | 2023-04-25 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6441f2b9e4bbbe4bbffc7d20/original/recital-vector-dot-operations-for-chemistry-students.pdf |
66e73ef912ff75c3a16cd0b5 | 10.26434/chemrxiv-2024-2jvfp | Highly Efficient Red Multi-Resonant Thermally Activated Delayed Fluorescence Emitters as Bioimaging Reagents | Multi-resonant thermally activated delayed fluorescence (MR-TADF) emitters have attracted strong interest for organic electroluminescent devices due to their high photoluminescence quantum yield (ΦPL) and superior narrowband emission, resulting in high color purity output in the device. These properties are also crucial for high-performance biological probes, especially red emitters. Orange and red MR-TADF emitters, PhDPA-DiKTa and MeODPA-DiKTa, were designed by decorating the DiKTa core with di([1,1’-biphenyl]-4-yl)amine (PhDPA) and bis(4-methoxyphenyl)amine (MeODPA). Both compounds emit at long wavelengths, with PL of 592 nm (full-width at half-maximum, FWHM = 45 nm) for PhDPA-DiKTa and 633 nm (FWHM= 72 nm) for MeODPA-DiKTa in toluene. As 5 wt% doped films in mCP, PhDPA-DiKTa emits at PL of 617 nm, while MeODPA-DiKTa emits at PL of 655 nm. Both show delayed fluorescence, with delayed lifetimes, td, of 658.4 and 249.2 s, respectively. Water-dispersible glassy organic dots (g-Odots) based on these materials were prepared by encapsulating them and mCP host into an amphiphilic DSPE-PEG2k polymer. Both families of g-Odots showed a deeper red emission and enhanced ΦPL compared to the corresponding 5 wt% doped films in mCP (PL = 618 nm, PL = 77% for PhDPA-DiKTa g-Odots, PL = 663 nm, PL = 38% for MeODPA-DiKTa g-Odots). The TADF character of the emitters was conserved in the g-ODots, with d of 203.9 s for PhDPA-DiKTa g-Odots and 131.6 s for MeODPA-DiKTa g-Odots. These MR-TADF g-Odots were successfully demonstrated as biological imaging probes of HeLa cells. | Changfeng Si; William Primrose; Yan Xu; Zachary Hudson; Eli Zysman-Colman | Biological and Medicinal Chemistry; Organic Chemistry; Organic Compounds and Functional Groups; Physical Organic Chemistry; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2024-09-17 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66e73ef912ff75c3a16cd0b5/original/highly-efficient-red-multi-resonant-thermally-activated-delayed-fluorescence-emitters-as-bioimaging-reagents.pdf |
65c374d9e9ebbb4db9d84df2 | 10.26434/chemrxiv-2024-91gvl | Alkyl–π Functional Molecular Gels: Control of Elastic
Modulus and Improvement of Electret Performance | The development of optoelectronically-active soft materials is drawing attention to the application of soft electronics. A room-temperature solvent-free liquid obtained by modifying a π-conjugated moiety with flexible yet bulky alkyl chains is a promising functional soft material. Tuning the elastic modulus (G′) is essential for employing optoelectronically-active alkyl–π liquids in deformable devices. However, the range of G′ achieved through the molecular design of alkyl–π liquids is limited. We report herein a method for controlling G′ of alkyl–π liquids by gelation. Adding 1 wt% low-molecular-weight gelator formed the alkyl–π functional molecular gel (FMG) and increased G′ of alkyl–π liquids by up to seven orders of magnitude while retaining the optical properties. Because alkyl–π FMGs have functional π-moieties in the gel medium, this new class of gels has a much higher content of π-moieties of up to 59 wt% compared to conventional π-gels of only a few wt%. More importantly, the gel state has a 23% higher charge-retention capacity than the liquid, providing better performance in deformable mechanoelectric generator-electret devices. The strategy used in this study is a novel approach for developing next-generation optoelectronically-active FMG materials. | Akito Tateyama; Kazuhiko Nagura; Masamichi Yamanaka; Takashi Nakanishi | Materials Science; Polymer Science; Dyes and Chromophores; Elastic Materials; Hydrogels; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-02-08 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65c374d9e9ebbb4db9d84df2/original/alkyl-functional-molecular-gels-control-of-elastic-modulus-and-improvement-of-electret-performance.pdf |
60c746cf702a9bcd9418aca4 | 10.26434/chemrxiv.10304258.v2 | Effect of Environmental Humidity on the Ionic Transport of Poly(ethylene Oxide) Thin Films by Local Dielectric Spectroscopy | <div><div><div><p>The effect of humidity on the ionic transport in the amorphous phase of poly(ethylene oxide) thin films has been studied by via local dielectric spectroscopy. We explored a controlled humidity range between 15 %RH and 50 %RH. AFM-based local dielectric imaging allowed to obtain simultaneously the thin films topography and the corresponding dielectric contrast maps. No humidity effect on the film topography was observed whereas large variation of the dielectric signal could be detected. In addition, we observed a clear dielectric contrast in different locations on the thin film surface. At selected regions with high contrast in the dielectric maps, we performed nanoDielectric Spectroscopy (nDS) measurements covering the frequency range from 10 Hz to 100 kHz. By modeling these spectroscopy results, we quantified the conductivity of the amorphous phase of the semicrystalline poly(ethylene oxide) films. The crystalline fraction of the PEO thin films was extracted and found to be about 36%, independently of humidity. However, the average conductivity increased drastically from 2×10-10 to 5×10-9 S/cm, by changing environmental humidity in the explore %RH range.</p></div></div></div> | Paul Markus; Daniel E Martínez-Tong; Georg Papastavrou; Angel Alegria | Nanostructured Materials - Materials; Polyelectrolytes - Materials; Thin Films; Polyelectrolytes - Polymers; Nanostructured Materials - Nanoscience; Transport phenomena (Physical Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2019-12-18 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c746cf702a9bcd9418aca4/original/effect-of-environmental-humidity-on-the-ionic-transport-of-poly-ethylene-oxide-thin-films-by-local-dielectric-spectroscopy.pdf |
67994dea81d2151a02552ccf | 10.26434/chemrxiv-2025-bxf47 | Characterizing the conformational ensemble of PROTAC degraders in solutions via atomistic simulations | Targeted protein degradation has emerged as a promising strategy for developing novel therapeutics, particularly for "undruggable" disease-related proteins. One approach is the use of PROteolysis TArgeting Chimeras (PROTACs) degraders, which induce the formation of ternary complexes between the target protein and E3 ligase, leading to ubiquitination and degradation of the target protein. Understanding the conformational behavior of PROTACs in solutions and how it relates to their pharmacokinetic properties is crucial for optimizing PROTAC design and efficacy. Due to the large size and flexibility of PROTACs and their chameleonic character, it is essential to understand their conformational ensemble, and how it depends on the environment, rather than considering a single structure. Here, we introduce a novel methodology for exploring PROTAC conformational behavior using atomistic simulations. We employ the enhanced sampling method Parallel-Bias Metadynamics, where we bias generic local collective variables, specifically all rotatable dihedral angles, thereby avoiding the considerable challenge of identifying suitable global collective variables for biasing. The methodology allows for obtaining free energy surfaces of global CVs via reweighting, thus giving valuable insight into the conformational ensemble. We apply the method to the prototypical case of the MZ1 PROTAC degrader, which targets bromodomain-containing protein-4 (BRD4) for degradation via the von Hippel-Lindau (VHL) E3 ligase, and elucidate its conformational behavior in different solvents, allowing us to gain insights into the chameleonic property of MZ1. Our methodological framework is generally applicable to large flexible molecules like PROTACs and the results demonstrate its efficiency, laying the groundwork for similar investigations for other PROTACs and other "beyond-rule-of-5" drug candidates. This work provides valuable insights into the design and optimization of PROTACs, ultimately contributing to developing novel therapeutics for "undruggable" diseases. | Shikshya Bhusal; Omar Valsson | Theoretical and Computational Chemistry; Physical Chemistry; Biological and Medicinal Chemistry; Biochemistry; Drug Discovery and Drug Delivery Systems; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67994dea81d2151a02552ccf/original/characterizing-the-conformational-ensemble-of-protac-degraders-in-solutions-via-atomistic-simulations.pdf |
60c75728567dfe5848ec661a | 10.26434/chemrxiv.14377049.v1 | Efficiency Gains for Thermally Coupled Solar Hydrogen Production in Extreme Cold | Hydrogen produced from water using solar energy constitutes a sustainable alternative to fossil fuels, but solar hydrogen is not yet economically competitive. A major question is whether the approach of coupling photovoltaics via the electricity grid to electrolysis is preferential to higher levels of device integration in ‘artificial leaf’ designs. Here, we scrutinise the effects of thermally coupled solar water splitting on device efficiencies and catalyst footprint for sub-freezing ambient temperatures of -20C. These conditions are found for a significant fraction of the year in many world regions. Using a combination of electrochemical experiments and modelling, we demonstrate that thermal coupling broadens the operating window and significantly reduces the required catalyst loading when compared to electrolysis decoupled from photovoltaics. Efficiency benefits differ qualitatively for double- and triple junction solar absorbers, which has implications for the general design of outdoor-located photoelectochemical devices. Similar to high-efficiency photovoltaics that reached technological maturity in space, application cases in polar or alpine climates could support the scale-up of solar hydrogen at the global scale. | Moritz Kölbach; Kira Rehfeld; Matthias May | Electrochemistry; Energy Storage | CC BY NC 4.0 | CHEMRXIV | 2021-04-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75728567dfe5848ec661a/original/efficiency-gains-for-thermally-coupled-solar-hydrogen-production-in-extreme-cold.pdf |
65c216ff66c138172912648f | 10.26434/chemrxiv-2024-wp120 | Quantum-quantum and quantum-quantum-classical schemes with projection-based-embedded $GW$-Bethe--Salpeter Equation | We present quantum-quantum and quantum-quantum-classical schemes based on many-body Green's functions theory in the $GW$ approximation with the Bethe--Salpeter equation ($GW$-BSE) employing projection-based-embedding (PbE). Such approaches allow defining active and inactive subsystems of larger, complex molecular systems, with only the smaller active subsystem being explicitly treated by $GW$-BSE offering significant computational advantages. However, as PbE can modify the single-particle states in the ground state calculation and screening effects from inactive region are not automatically included in $GW$-BSE, results from such PbE-$GW$-BSE calculations can deviate from a full-system reference. Here, we scrutinize in detail, e.g., the individual and combined effects of different choices of active regions, the influence of screening from the inactive region, and strategies for basis set truncation on frontier orbital and near-gap electron-hole excitation energies. As prototypical systems, we consider a diketopyrrolopyrrole bicyclic ring including side-chains, a polarity-sensitive dye (prodan) in aqueous environment, and a $\pi$-stacked dimer of benzene and tetracyanoethylene in water, respectively, covering a variety of excitation characters in molecular systems with complex chemical environments and photoinduced processes. | Vivek Sundaram; Björn Baumeier | Theoretical and Computational Chemistry; Computational Chemistry and Modeling; Theory - Computational | CC BY NC ND 4.0 | CHEMRXIV | 2024-02-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65c216ff66c138172912648f/original/quantum-quantum-and-quantum-quantum-classical-schemes-with-projection-based-embedded-gw-bethe-salpeter-equation.pdf |
639a4e94e8047a9581e906aa | 10.26434/chemrxiv-2022-3j68j | Biorenewable Circularity in Polydiketoenamine
Plastics | Here, we show that by incorporating the
polyketide triacetic acid lactone (TAL) in polydiketoenamines (PDK), we increase the
working temperature of these circular plastics, opening the door wider to applications where
circularity is urgently needed. | Jeremy Demarteau; Benjamin Cousineau; Zilong Wang; Baishakhi Bose; Seokjung Cheong; Guangxu Lan; Nawa Baral; Simon Teat; Corinne Scown; Jay Keasling; Brett Helms | Polymer Science; Energy; Biopolymers; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2022-12-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/639a4e94e8047a9581e906aa/original/biorenewable-circularity-in-polydiketoenamine-plastics.pdf |
65043a5099918fe537fdbccb | 10.26434/chemrxiv-2023-lfnlp | Gas Evolution as a Tool to study Reaction Kinetics under Biomimetic Conditions | The rational development of transition metal-based catalysts requires detailed kinetic analysis of catalytic reactions to aid catalyst design. Whereas kinetic data is relatively easy to obtain for catalysts used in synthetic applications, it is more challenging to study catalytic reactions for potential use in living systems, a rapidly growing field. In such applications, substantial concentrations of salts and biomolecules are present in the reaction medium, hampering the use of typically employed solution-phase analytical techniques. In this study, we explored the suitability of gas evolution as a probe to study kinetics under biomimetic conditions. As proof of concept, we demonstrate that the progress of two transition metal catalyzed bioorthogonal chemical reactions can be accurately monitored, regardless of the complexity of the medium. As such, we introduce a protocol to gain more insight into the performance of a catalytic system under biologically relevant conditions to progress iterative catalyst development for in vivo applications. | Eva Meeus; Pieter Laan ; Rens Ham ; Bas de Bruin ; Joost Reek | Organic Chemistry; Catalysis; Organometallic Chemistry; Homogeneous Catalysis; Kinetics and Mechanism - Organometallic Reactions | CC BY NC 4.0 | CHEMRXIV | 2023-09-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65043a5099918fe537fdbccb/original/gas-evolution-as-a-tool-to-study-reaction-kinetics-under-biomimetic-conditions.pdf |
60c75734ee301c63ebc7b4bf | 10.26434/chemrxiv.14378681.v1 | Microfluidic-like Fabrication of a Vanadium-Cured Bioadhesive by Mussels | <p>To anchor in
seashore habitats, mussels fabricate adhesive byssus fibers mechanically
reinforced by protein-metal coordination mediated via
3,4-dihydroxyphenylalanine (DOPA) – providing a well-established role model for
bio-inspired design of smart metallopolymers and underwater glues. However,
currently, the mechanism by which metal ions are integrated as cross-links
during byssus formation is completely unknown. Here, we investigated the byssus
formation process, combining traditional and advanced methods to identify how
and when metals are incorporated into the material. We discovered that mussels
concentrate and store iron and vanadium ions in intracellular metal storage
particles (MSPs) complexed with previously unknown catechol-based storage
molecules. During thread formation, stockpiled secretory vesicles containing
concentrated fluid proteins are mixed with MSPs within a complex
microfluidic-like network of interconnected channels where they coalesce
forming protein-metal bonds within the nascent byssus. These insights are
important for bio-inspired materials design, but also from a biological and
chemical perspective – the active accumulation and utilization of vanadium is
extremely rare in nature.</p> | Tobias Priemel; Gurveer Palia; Frank Förste; Franziska Jehle; Ioanna Mantouvalou; Paul Zaslansky; Luca Bertinetti; Matthew Harrington | Biological Materials; Materials Processing; Biopolymers; Coordination polymers; Bioinorganic Chemistry; Biochemistry; Bioorganometallic Chemistry; Coordination Chemistry (Organomet.); Ligands (Organomet.); Transition Metal Complexes (Organomet.); Self-Assembly | CC BY NC ND 4.0 | CHEMRXIV | 2021-04-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75734ee301c63ebc7b4bf/original/microfluidic-like-fabrication-of-a-vanadium-cured-bioadhesive-by-mussels.pdf |
60ea0828b9b601af93232fd3 | 10.26434/chemrxiv-2021-6s3s3 | Long-range interactions boost singlet exciton diffusion in nanofibers of $\pi$-extended polymer chains | Raising the distance covered by singlet excitons during their lifetimes to values maximizing light absorption (a few hundred nm) would solve the exciton diffusion bottleneck issue and lift the constraint for fine (~10 nm) phase segregation in bulk heterojunction organic solar cells. In that context, the recent report of highly ordered conjugated polymer nanofibers featuring singlet exciton diffusion length, $L_D$, in excess of 300 nm is both appealing and intriguing [X. Jin et al., Science 360, 897 (2018)]. Here, on the basis of non-adiabatic molecular dynamics simulations, we demonstrate that singlet exciton diffusion in poly(3-hexylthiophene) (P3HT) fibers is highly sensitive to the interplay between delocalization along the polymer chains and long-range interactions along the stacks. Remarkably, the diffusion coefficient is predicted to rocket by three orders of magnitude when going beyond nearest-neighbor intermolecular interactions in fibers of extended (30-mer) polymer chains and to be resilient to interchain energetic and positional disorders. | Suryoday Prodhan; Samuele Giannini; Linjun Wang; David Beljonne | Theoretical and Computational Chemistry; Theory - Computational | CC BY 4.0 | CHEMRXIV | 2021-07-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60ea0828b9b601af93232fd3/original/long-range-interactions-boost-singlet-exciton-diffusion-in-nanofibers-of-pi-extended-polymer-chains.pdf |
6564cb5acf8b3c3cd7407017 | 10.26434/chemrxiv-2023-zsdx8 | A High-Throughput Workflow for Mass Spectrometry Analysis of Nucleic Acids by Nanoflow Desalting | Broad interest in nucleic acids – both their therapeutic capabilities and understanding the nuances of their structure and resulting function – has increased in recent years. Post-transcriptional modifications in particular have become an important analysis target, as these covalent modifications to the sugars, nitrogenous bases, and phosphate backbone impart differential functionality to synthetic and biological nucleic acids. Characterizing these post-transcriptional modifications can be difficult with traditional sequencing workflows; however, advancements in top-down mass spectrometry address these challenges. On-line desalting platforms have enabled facile sample clean-up and reliable ionization of increasingly large (100 nt) oligonucleotides, and application of existing tandem mass spectrometry techniques have yielded information-rich spectra which can be used to interrogate primary sequences. To extend the capabilities of top-down MS and in its analysis of nucleic acids, we have developed a nanoflow desalting platform for high-throughput and low sample-use desalting coupled with collision-induced dissociation (CID), 213 nm ultraviolet photodissociation (UVPD) and activated-ion electron photodetachment dissociation (a-EPD) to yield high-quality MS/MS spectra. Fragments identified using an m/z-domain isotope matching strategy yielded high sequence coverage (>70%) of a yeast phenylalanine tRNA. | Michael Lanzillotti; Jennifer Brodbelt | Analytical Chemistry; Mass Spectrometry | CC BY 4.0 | CHEMRXIV | 2023-11-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6564cb5acf8b3c3cd7407017/original/a-high-throughput-workflow-for-mass-spectrometry-analysis-of-nucleic-acids-by-nanoflow-desalting.pdf |
60c740a0bb8c1a06513d9df8 | 10.26434/chemrxiv.7247045.v2 | QUBEKit: Automating the Derivation of Force Field Parameters from Quantum Mechanics | <div><div><div><p>Modern molecular mechanics force fields are widely used for modelling the dynamics and interactions of small organic molecules using libraries of transferable force field parameters. For molecules outside the training set, parameters may be missing or inaccurate, and in these cases, it may be preferable to derive molecule-specific parameters. Here we present an intuitive parameter derivation toolkit, QUBEKit (QUantum mechanical BEspoke Kit), which enables the automated generation of system-specific small molecule force field parameters directly from quantum mechanics. QUBEKit is written in python and combines the latest QM parameter derivation methodologies with a novel method for deriving the positions and charges of off-center virtual sites. As a proof of concept, we have re-derived a complete set of parameters for 109 small organic molecules, and assessed the accuracy by comparing computed liquid properties with experiment. QUBEKit gives highly competitive results when compared to standard transferable force fields, with mean unsigned errors of 0.024 g/cm3, 0.79 kcal/mol and 1.17 kcal/mol for the liquid density, heat of vaporization and free energy of hydration respectively. This indicates that the derived parameters are suitable for molecular modelling applications, including computer-aided drug design.</p></div></div></div> | Joshua Horton; Alice Allen; Leela Dodda; Daniel Cole | Computational Chemistry and Modeling; Theory - Computational; Quantum Mechanics | CC BY 4.0 | CHEMRXIV | 2019-02-11 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c740a0bb8c1a06513d9df8/original/qube-kit-automating-the-derivation-of-force-field-parameters-from-quantum-mechanics.pdf |
6577993afd283d7904ca6b93 | 10.26434/chemrxiv-2023-vwwtn-v2 | Quantitively Differentiating Antibodies Using Charge-State Manipulation, Collisional Activation, and Ion Mobility – Mass Spectrometry | Antibody-based therapeutics continue to expand both in the number of products and their use in patients. These heterogeneous proteins challenge traditional drug characterization strategies, but ion mobility (IM) – mass spectrometry (MS) approaches have eased the challenge of higher-order structural characterization. Energy-dependent IM-MS, e.g., collision-induced unfolding (CIU), has been demonstrated to be sensitive to subtle differences in structure. In the present study, we combine a charge-reduction method, cation-to-anion proton-transfer reactions (CAPTR), with energy-dependent IM-MS and varied solution conditions to probe their combined effects on the gas-phase structures of IgG1κ and IgG4κ from human myeloma. CAPTR paired with MS-only analysis improves the confidence of charge-state assignments and the resolution of interfering protein species. Collision cross-section distributions were determined for each of the charge-reduced products. Similarity scoring was used to quantitively compare distributions determined from matched experiments analyzing samples of the two antibodies. Relative to workflows using energy-dependent IM-MS without charge-state manipulation, combining CAPTR and energy-dependent IM-MS enhanced the differentiation of these antibodies. Combined, these results indicate that CAPTR can benefit many aspects of antibody characterization and differentiation. | Theresa A. Gozzo; Matthew F. Bush | Biological and Medicinal Chemistry; Analytical Chemistry; Mass Spectrometry; Biophysics | CC BY NC ND 4.0 | CHEMRXIV | 2023-12-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6577993afd283d7904ca6b93/original/quantitively-differentiating-antibodies-using-charge-state-manipulation-collisional-activation-and-ion-mobility-mass-spectrometry.pdf |
6780e62b6dde43c908fa0bd7 | 10.26434/chemrxiv-2024-vnwg3-v2 | Stereoselective Synthesis of Mirogabalin via 1,4-Selective Addition of Lithioacetonitrile to Alkylidene Malonate | The synthesis of mirogabalin was studied for industrial production, and an alternative to the Daiichi–Sankyo’s method was established. The developed synthesis involves the introduction of a two-carbon unit with the stereoselective 1,4-selective addition of lithioacetonitrile to alkylidene malonate and one-carbon degradation by Hofmann rearrangement. The precursor for the Hofmann rearrangement was readily prepared from the 1,4-adduct via a one-pot reaction involving decarboxylation, hydrolysis, and hydration. | Hidenori Ochiai; Taiki Mihara; Miwa Sasagawa; Akira Nishiyama | Organic Chemistry; Organic Synthesis and Reactions; Process Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-10 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6780e62b6dde43c908fa0bd7/original/stereoselective-synthesis-of-mirogabalin-via-1-4-selective-addition-of-lithioacetonitrile-to-alkylidene-malonate.pdf |
60c74bb8f96a00fe94287686 | 10.26434/chemrxiv.12375047.v1 | Revisiting Catalytic Cycles: A Broader View Through the Energy Span Model | <div><div><div><p>The computational study of catalytic processes allows discovering really intricate and detailed reaction mechanisms that involve many species and transformations. This increasing level of detail can even result detrimental when drawing conclusions from the computed mechanism, as many co-existing reaction pathways can be in close com- petence. Here we present a reaction network-based implementation of the energy span model in the form of a computational code, gTOFfee, capable of dealing with any user-specified reaction network. This approach, compared to microkinetic simulations, enables a much easier and straightforward analysis of the performance of any catalytic reaction network. In this communication, we will go through the foundations and appli- cability of the underlying model, and will tackle the application to two relevant catalytic systems: homogeneous Co-mediated propene hydroformylation and heterogeneous CO2 hydrogenation over Cu(111).</p></div></div></div> | Diego Garay-Ruiz; Carles Bo | Heterogeneous Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2020-05-28 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74bb8f96a00fe94287686/original/revisiting-catalytic-cycles-a-broader-view-through-the-energy-span-model.pdf |
66589282418a5379b0ac8928 | 10.26434/chemrxiv-2023-p2g9h-v3 | Enabling Cellular Resolution Molecular Pathology for Surgical Interventions Using Laser Desorption – Rapid Evaporative Ionization Mass spectrometry | Laser desorption ionization (LDI) is generally considered to be an inferior ionization modality to matrix assisted LDI (MALDI), providing information solely on lipids with low sensitivity. The current study demonstrates that the combination of ambient LDI with in-source surface-induced declustering provides sensitivity and chemical coverage comparable to MALDI. The setup was characterised for infrared laser desorption using two different laser systems and was successfully used for ambient mass spectrometric imaging. 5 µm spatial resolution was achieved enabling single-cell resolution imaging, while metabolites and lipids ranging from amino acids through carbohydrates and nuclear bases to complex glycolipids were successfully detected. The technique was also tested as a platform for MS-guided surgery, raising the possibility of using a single technique for generating histological and in-vivo data. The results suggest that the method can be an important step forward in histological classification for surgery and pathology environments, potentially offering a versatile platform for generating both histological and in vivo data. | Daniel Simon; Gabriel Stefan Horkovics-Kovats; Yuchen Xiang; Ronan Battle; Yu Wang; Julia Abda; Dimitris Papanastasiou; Stefania Maneta; Hui-Yu Ho; Haixing Wang; Richard Schäffer; Tamas Karancsi; Anna Mroz; Istvan Pap; Laurine Lagache; Julia Balog; Isabelle Fournier; Robert Murray; Josephine Bunch; Zoltan Takats | Biological and Medicinal Chemistry; Analytical Chemistry; Imaging; Mass Spectrometry | CC BY NC ND 4.0 | CHEMRXIV | 2024-05-31 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66589282418a5379b0ac8928/original/enabling-cellular-resolution-molecular-pathology-for-surgical-interventions-using-laser-desorption-rapid-evaporative-ionization-mass-spectrometry.pdf |
6522eefd45aaa5fdbb8eb44f | 10.26434/chemrxiv-2023-cdrxf | Introducing SpectraFit: An Open-Source Tool for Interactive Spectral Analysis. | In chemistry, analyzing spectra through peak fitting is a crucial task that helps scientists extract useful quantitative information about a sample's chemical composition or electronic structure. To make this process more efficient, we have developed a new open-source software tool called SpectraFit. This tool allows users to perform quick data fitting using regular expressions of distribution and linear functions through the command line interface (CLI) or Jupyter Notebook, which can run on Linux, Windows, and MacOS, as well as in a Docker container.
As part of our commitment to good scientific practice, we have introduced an output file-locking system to ensure the accuracy and consistency of information. This system collects input data, results data, and the initial fitting model in a single file, promoting transparency, reproducibility, collaboration, and innovation.
To demonstrate SpectraFit's user-friendly interface and the advantages of its output file-locking system, we are focusing on a series of previously published iron-sulfur dimers and their XAS spectra. We will show how to analyze the XAS spectra via CLI and in a Jupyter Notebook by applying a global fitting routine. Additionally, we will demonstrate how SpectraFit can be used as a black box and white box solution, allowing users to apply their own algorithms to engineer the data further.
The publication, along with its supplementary information, serves as a playbook to guide users through each step of the process. SpectraFit will streamline the peak fitting process and prove to be an invaluable resource for chemists and other professionals working in related fields. | Anselm W. Hahn; Joseph Zsombor-Pindera; Pierre Kennepohl; Serena DeBeer | Theoretical and Computational Chemistry; Inorganic Chemistry; Spectroscopy (Inorg.); Transition Metal Complexes (Inorg.); Computational Chemistry and Modeling | CC BY 4.0 | CHEMRXIV | 2023-10-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6522eefd45aaa5fdbb8eb44f/original/introducing-spectra-fit-an-open-source-tool-for-interactive-spectral-analysis.pdf |
60c748190f50db7b06396713 | 10.26434/chemrxiv.9733628.v2 | Rationalizing the diverse reactivity of [1.1.1]propellane through sigma-pi-delocalization | <p>[1.1.1]Propellane has gained increased attention due to its utility as a precursor to bicyclo[1.1.1]pentanes (BCPs) – motifs of high value in pharmaceutical and materials research – by addition of nucleophiles, radicals and electrophiles across its inter-bridgehead C–C bond. However, the origin of this broad reactivity profile is not well-understood. Here, we present a comprehensive computational study that attributes the omniphilicity of [1.1.1]propellane to a moldable, delocalized electron density, characterized by the mixing of the inter-bridgehead C–C bonding and antibonding orbitals. Reactions with anions and radicals are facilitated by stabilization of the adducts through sigma-pi-delocalization of electron density over the cage, while reactions with cations involve charge transfer that relieves Pauli repulsion inside the cage. These results provide a unified framework to rationalize propellane reactivity, opening up opportunities for the exploration of new chemistry of [1.1.1]propellane and related strained systems. </p> | Alistair Sterling; Alexander Durr; Russell C. Smith; Edward Anderson; Fernanda Duarte | Organic Compounds and Functional Groups; Physical Organic Chemistry; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2020-02-07 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c748190f50db7b06396713/original/rationalizing-the-diverse-reactivity-of-1-1-1-propellane-through-sigma-pi-delocalization.pdf |
66de67c951558a15ef7633be | 10.26434/chemrxiv-2024-g0mdn | The FTIR-ATR Spectroscopy and Multivariate Data Analysis (MVDA) for Halal Authentication on Animal Fatty Acids | The authentication of halal products is crucial for adherents of Islam, as consuming non-permissible substances contradicts religious mandates. Recent widespread adulteration of food and pharmaceutical products with porcine-derived ingredients has necessitated the development of robust analytical methods for halal verification. This study presents an approach for rapid halal authentication using Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) combined with multivariate data analysis (MVDA). Animal fats from beef, chicken, pork (lard) and goat, along with palm oil, were extracted via Soxhlet apparatus utilizing petroleum ether as solvent. The FTIR-ATR spectra were acquired in the mid-infrared region (4000 – 650 cm-1), encompassing both fingerprint and functional group region. The principal component analysis (PCA) was employed to identify unique spectral patterns and develop classification models for halal authentication. The combination of FTIR-ATR and MVDA techniques meanwhile enables the identification of characteristic spectral features and the development of classification models for halal authentication. The PCA result revealed clear clustering of samples based on their origin, with total variance range of 74.75 – 98.79% explained by the first two principal components based on all FTIR spectra of wavenumber 4000 – 650 cm-1, respectively. This FTIR-ATR coupled with MVDA approach offers a rapid, non-destructive and cost-effective method for halal authentication. The technique’s high sensitivity and specificity make it a promising tool for regulatory bodies and food manufacturers to ensure compliance with halal standards. | Muhammad Zulhelmi Nazri; Norliza Abdul Latiff; Siti Nor Azlina Abd Rashid; Salimah Ab Malik; Hajar Aminah A. Karim; Muhamad Shirwan Abdullah Sani; Dayang Norulfairuz Abang Zaidel; Norazah Basar | Analytical Chemistry; Separation Science; Spectroscopy (Anal. Chem.) | CC BY NC ND 4.0 | CHEMRXIV | 2025-01-02 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66de67c951558a15ef7633be/original/the-ftir-atr-spectroscopy-and-multivariate-data-analysis-mvda-for-halal-authentication-on-animal-fatty-acids.pdf |
617af622f9f05bbea0e43d6e | 10.26434/chemrxiv-2021-frfhz-v2 | Machine Learning of Reaction Properties via Learned Representations of the Condensed Graph of Reaction | The estimation of chemical reaction properties such as activation energies, rates or yields is a central topic of computational chemistry. In contrast to molecular properties, where machine learning approaches such as graph convolutional neural networks (GCNNs) have excelled for a wide variety of tasks, no general and transferable adaptations of GCNNs for reactions have been developed yet. We therefore combined a popular cheminformatics reaction representation, the so-called condensed graph of reaction (CGR), with a recent GCNN architecture to arrive at a versatile, robust and compact deep learning model. The CGR is a superposition of the reactant and product graphs of a chemical reaction, and thus an ideal input for graph-based machine learning approaches. The model learns to create a data-driven, task dependent reaction embedding that does not rely on expert knowledge, similar to current molecular GCNNs. Our approach outperforms current state-of-the-art models in accuracy, is applicable even to imbalanced reactions and possesses excellent predictive capabilities for diverse target properties, such as activation energies, reaction enthalpies, rate constants, yields or reaction classes. We furthermore curated a large set of atom-mapped reactions along with their target properties, which can serve as benchmark datasets for future work. All datasets and the developed reaction GCNN model are available online, free of charge and open-source. | Esther Heid; William H. Green | Theoretical and Computational Chemistry; Computational Chemistry and Modeling; Machine Learning | CC BY NC ND 4.0 | CHEMRXIV | 2021-10-29 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/617af622f9f05bbea0e43d6e/original/machine-learning-of-reaction-properties-via-learned-representations-of-the-condensed-graph-of-reaction.pdf |
63ec01c5fcfb27a31fcb098c | 10.26434/chemrxiv-2022-t7vmq-v3 | Rational Design of the beta-Bulge Gate in a Green Fluorescent Protein Accelerates the Kinetics of Sulfate Sensing | Detection of anions in complex aqueous media is a fundamental challenge with practical utility that can be addressed by supramolecular chemistry. Biomolecular hosts such as proteins can be used and adapted as an alternative to synthetic hosts. Here, we report how the mutagenesis of the beta-bulge residues (D137 and W138) in mNeonGreen, a bright, monomeric fluorescent protein, unlocks and tunes the anion preference at physiological pH for sulfate, resulting in the turn-off sensor SulfOFF-1. This unprecedented sensing arises from an enhancement in the kinetics of binding, largely driven by position 138. In line with these data, molecular dynamics (MD) simulations capture how the coordinated entry and gating of sulfate into the beta-barrel is eliminated upon mutagenesis to facilitate binding and fluorescence quenching. | Whitney S. Y. Ong; Ke Ji; Vishaka Pathiranage; Caden Maydew; Kiheon Baek; Rhiza Lyne E. Villones; Gabriele Meloni; Alice R. Walker; Sheel Dodani | Theoretical and Computational Chemistry; Biological and Medicinal Chemistry; Biochemistry; Biophysics; Computational Chemistry and Modeling | CC BY NC ND 4.0 | CHEMRXIV | 2023-02-15 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63ec01c5fcfb27a31fcb098c/original/rational-design-of-the-beta-bulge-gate-in-a-green-fluorescent-protein-accelerates-the-kinetics-of-sulfate-sensing.pdf |
65ec6e28e9ebbb4db954201d | 10.26434/chemrxiv-2024-5ls6h | Thermal Truncation of Heptamethine Cyanine Dyes | Cyanine dyes are a class of organic, usually cationic molecules containing two nitrogen centers linked through conjugated polymethine chains. Unlike phototruncation, the thermal truncation (chain-shortening) reaction is a phenomenon that has rarely been described for these important fluorophores. Here, we present a systematic investigation of the truncation of heptamethine cyanines (Cy7) to pentamethine (Cy5) and trimethine (Cy3) cyanines via homogeneous, acid-base catalyzed nucleophilic exchange reactions. We demonstrate how different substituents at the C3′ and C4′ positions of the chain and dif-ferent heterocyclic end groups, the presence of different bases, nucleophiles and oxygen, solvent properties, and tempera-ture affect the truncation process. The mechanism of chain shortening, studied by various analytical and spectroscopic techniques, was verified by extensive ab initio calculation, demonstrating the need to model catalytic reactions by highly correlated wavefunction-based methods. We show that entropic effects control the course of this process. The study provides a critical insight into the reactivity of the polyene chains of cyanines and offers new approaches to the synthesis of meso-substituted symmetrical and unsymmetrical pentamethine cyanines from Cy7 derivatives. | Jana Okorocenkova; Josef Filgas; Nasrulla M. Khan; Petr Slavicek; Petr Klán | Organic Chemistry; Organic Synthesis and Reactions; Physical Organic Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2024-03-12 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65ec6e28e9ebbb4db954201d/original/thermal-truncation-of-heptamethine-cyanine-dyes.pdf |
611c5e67032be76b52e868b8 | 10.26434/chemrxiv-2021-xt242 | Cooperative C-O Bond Activation by a Heterobinuclear Al-Fe Complex Operating by a Radical Pair Mechanism | Activation of inert molecules like CO2 is often mediated by cooperative chemistry between two reactive sites within a cata-lytic assembly, the most common form of which is Lewis acid/base bifunctionality observed in both natural metalloenzymes and synthetic systems. Here, we disclose a heterobinuclear complex with an Al-Fe bond that instead activates CO2 and other substrates through cooperative behavior of two radical intermediates. The complex L(Me)Al-Fp (2, L = HC{(CMe)(2,6-iPr2C6H3N)}2, Fp = FeCp(CO)2) was found to insert CO2 and cyclohexene oxide, producing LAl(Me)(µ:κ2-O2C)Fp (3) and LAl(Me)(µ-OC6H10)Fp (4), respectively. Further atom transfer, decarbonylation, and isomerization reactivity was also ob-served. Detailed mechanistic studies on the CO2 and epoxide insertion reactions indicate an unusual mechanism in which (i) the Al-Fe bond dissociates homolytically to generate formally AlII and FeI metalloradicals, then (ii) the metalloradicals add to substrate in a pairwise fashion initiated by O-coordination to Al. The accessibility of this unusual mechanism is aided, in part, by the redox non-innocent nature of L that stabilizes formally AlII intermediates with predominantly AlIII-like character. This “radical pair” pathway represents an unprecedented mechanism for CO2 activation. | Soumen Sinhababu; Maxim Radzhabov; Neal Mankad | Inorganic Chemistry; Organometallic Chemistry; Frustrated Lewis Pairs; Kinetics and Mechanism - Organometallic Reactions; Small Molecule Activation (Organomet.) | CC BY NC ND 4.0 | CHEMRXIV | 2021-08-19 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/611c5e67032be76b52e868b8/original/cooperative-c-o-bond-activation-by-a-heterobinuclear-al-fe-complex-operating-by-a-radical-pair-mechanism.pdf |
630661bf90802dd2bd68c2ec | 10.26434/chemrxiv-2022-tnt07 | Analytical Evaluation of Lead Iodide Precursor Impurities Affecting Halide Perovskite Device Performance | Mirroring established semiconductor technologies, halide perovskite materials synthesized from higher quality reagents display improved optoelectronic performance. In this study, we performed a semiquantitative analytical characterization of five different commercial lead iodide sources to determine the identity and concentration of impurities that affect perovskite devices. It was possible to single out acetate (OAc) and potassium (K) as key species in as-received materials, both plausibly remnant from synthesis or purification. We removed these impurities through aqueous recrystallization revealing contrasting impacts on device performance: removal of OAc was beneficial but reducing K could be detrimental. This observation indicates that the highest purity lead iodide does not guarantee the highest performing perovskite material, since certain extrinsic impurities, such as KI, can improve device performance. Fundamental and applied studies will both benefit from improved purification procedures coupled with analytical studies to better understand and control the effects of individual impurities in halide perovskite materials. | Ross Kerner; Earl Christensen; Steven Harvey; Jonah Messinger; Severin Habisreutinger; Fei Zhang; Giles Eperon; Laura Schelhas; Kai Zhu; Joseph Berry; David Moore | Materials Science; Energy; Hybrid Organic-Inorganic Materials; Materials Processing; Photovoltaics; Materials Chemistry | CC BY 4.0 | CHEMRXIV | 2022-08-26 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/630661bf90802dd2bd68c2ec/original/analytical-evaluation-of-lead-iodide-precursor-impurities-affecting-halide-perovskite-device-performance.pdf |
630b4c1a0c52774721c5c9d6 | 10.26434/chemrxiv-2022-627gz | Proton Exchange Reaction in Acidic Zeolites: Mechanism and Free Energetics
| Conversion of alkanes to liquid fuels and other chemicals has a great demand in many industrial applications. The key challenge in the alkane conversion is the activation of the C-H bond. Protonated zeolites are known to activate the C-H bond in alkanes. Modeling of such catalytic reactions and estimation of reaction free energies especially when entropy has a non-negligible contribution in the reactant state due to the translational motion in the pores, is computationally challenging. Large size of the zeolite systems also poses difficulty in modelling such reactions. We address these problems through extensive fully relaxed hybrid quantum mechanics and molecular mechanics based molecular dynamics simulations, and free energy calculations using the temperature accelerated sliced sampling approach. We model proton exchange reaction between methane and Brønsted acid site of zeolite at 300 K. We investigate the differential reactivity of H-ZSM-5 and H-MCM-22 zeolites toward proton exchange, and probe the role of acidity, internal structure, and entropy.
| Rahul Verma; Nisanth Nair | Theoretical and Computational Chemistry; Physical Chemistry; Catalysis; Computational Chemistry and Modeling; Heterogeneous Catalysis; Quantum Mechanics | CC BY 4.0 | CHEMRXIV | 2022-08-30 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/630b4c1a0c52774721c5c9d6/original/proton-exchange-reaction-in-acidic-zeolites-mechanism-and-free-energetics.pdf |
6501d5ca99918fe537e3010f | 10.26434/chemrxiv-2023-4c415-v2 | Why Yttrium Hexaboride Exhibits a Much Higher Superconducting Tc than Near-Identical Lanthanum Hexaboride | Though YB6 and LaB6 share the same crystal structure, atomic valence electron configuration, and phonon modes, they exhibit drastically different phonon-mediated superconductivity. YB6 superconducts below 8.4 K, giving it the second-highest critical temperature of known borides. LaB6 does not superconduct until near-absolute zero temperatures, however. Though previous studies have quantified the canonical superconductivity descriptors of YB6’s greater Fermi-level (Ef) density of states and higher electron-phonon coupling (EPC), the root of this difference has not been assessed with full detail of the electronic structure. Through chemical bonding, we determine low-lying, unoccupied 4f atomic orbitals in lanthanum to be the key difference between these superconductors. These orbitals, which are not accessible in YB6, hybridize with pi B-B bonds and bring this pi-system lower in energy than the sigma B-B bonds otherwise at Ef. This inversion of bands is crucial: the phonon modes we show responsible for superconductivity cause the sigma-orbitals of YB6 to change drastically in overlap, but couple weakly to the pi-orbitals of LaB6. These phonons in YB6 even access an electronic-state crossing, indicating strong EPC. No such crossing in LaB6 is observed. Finally, a supercell (the M k-point) is shown to undergo a Peierls-like effect in YB6, introducing additional EPC. | Robert Lavroff; Julen Munarriz; Claire Dickerson; Francisco Munoz; Anastassia Alexandrova | Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Quantum Mechanics; Quasiparticles and Excitations; Materials Chemistry | CC BY NC ND 4.0 | CHEMRXIV | 2023-09-14 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6501d5ca99918fe537e3010f/original/why-yttrium-hexaboride-exhibits-a-much-higher-superconducting-tc-than-near-identical-lanthanum-hexaboride.pdf |
6227fe5450b6211c00ee8cfe | 10.26434/chemrxiv-2022-z90nh | Natural product inspired chiral ligand design: Aloperine induced asymmetric hydroarylation of ketimines under Pd catalysed conditions | A naturally occurring alkaloid aloperine was utilized as a core chiral skeleton for the development of new ligands. Using these chiral 1,3-diamine ligands, a Pd catalysed asymmetric hydroarylation of ketimines was reported. A range of chiral sulfonyl amides were prepared in high yields and enantioselectivties. The stereoselectivity and structure relationships of aloperine has been studied by the introduction of various subsitituents. These discoveries would provide a new future development for natural product inspired chiral ligand design and developments. | Xuegang Fu; Yuting Yan; Hexin Sun; Siying Li; Jianhui Huang | Catalysis; Homogeneous Catalysis | CC BY NC ND 4.0 | CHEMRXIV | 2022-03-09 | https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6227fe5450b6211c00ee8cfe/original/natural-product-inspired-chiral-ligand-design-aloperine-induced-asymmetric-hydroarylation-of-ketimines-under-pd-catalysed-conditions.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.