72,874 results match your criteria hydrogen bonding

Exploring the interactions of naringenin and naringin with trypsin and pepsin: Experimental and computational modeling approaches.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Apr 21;258:119859. Epub 2021 Apr 21.

School of Medical Engineering, Xinxiang Medical University, Xinxiang, Henan 453003, PR China. Electronic address:

Naringenin and naringin are two natural compounds with important health benefits, whether as food or drug. It is necessary to study the interactions between naringenin/naringin and digestive proteases, such as trypsin and pepsin. In this study, the bindings of naringenin and naringin to trypsin and pepsin were investigated using multi-spectroscopy analysis and computational modeling approaches. Read More

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Benzoic acid-modified monolithic column for separation of hydrophilic compounds by capillary electrochromatography with high content of water in mobile phase.

J Chromatogr A 2021 Apr 22;1647:462166. Epub 2021 Apr 22.

Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 100080, China. Electronic address:

Hydrophilic column combined with mobile phase containing high content of water is a green method for the separation of polar compounds, but there are few related studies, and the separation efficiency and performance of existing columns still needs to be improved. In this work, a novel monolithic column for separation of hydrophilic compounds under both high water content and HILIC condition, was prepared by in-situ polymerization using 4-vinylbenzoic acid (VBA) and 1-(Acryloyloxy)-3-(methacryloyloxy)-2-propanol (AMAP) as functional monomers. The poly(VBA-co-AMAP) monolithic column showed good separation performance towards various polar compounds under different chromatographic conditions based on the π-interaction, hydrophobic and hydrogen bonding interactions provided by 4-vinylbenzoic acid functional monomer. Read More

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Disaccharide Residues are Required for Native Antifreeze Glycoprotein Activity.

Biomacromolecules 2021 May 6. Epub 2021 May 6.

Max Planck Institute for Polymer Research, 55128 Mainz, Germany.

Antifreeze glycoproteins (AFGPs) are able to bind to ice, halt its growth, and are the most potent inhibitors of ice recrystallization known. The structural basis for AFGP's unique properties remains largely elusive. Here we determined the antifreeze activities of AFGP variants that we constructed by chemically modifying the hydroxyl groups of the disaccharide of natural AFGPs. Read More

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Screening of hydrogen bonding interactions by a single layer graphene.

Nanoscale 2021 May 6;13(17):8098-8106. Epub 2021 Apr 6.

School of Polymer Science and Polymer Engineering, University of Akron, Akron, OH 44325, USA.

A single layer of graphene when transferred to a solid substrate has the ability to screen or transmit interactions from the underlying substrate, which has direct consequences in applications of this 2D material to flexible electronics and sensors. Previous reports using a multitude of techniques present contradictory views on graphene's ability to screen or transmit van der Waals (vdW) and polar interactions. In the present study, we use interface-sensitive spectroscopy to demonstrate that a single layer graphene is opaque to hydrogen bonding interactions (a subset of acid-base interactions), answering a question that has remained unresolved for a decade. Read More

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Fundamental photophysics of isomorphic and expanded fluorescent nucleoside analogues.

Chem Soc Rev 2021 May 6. Epub 2021 May 6.

Laboratoire de Bioimagerie et Pathologies, UMR 7021, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France.

Fluorescent nucleoside analogues (FNAs) are structurally diverse mimics of the natural essentially non-fluorescent nucleosides which have found numerous applications in probing the structure and dynamics of nucleic acids as well as their interactions with various biomolecules. In order to minimize disturbance in the labelled nucleic acid sequences, the FNA chromophoric groups should resemble the natural nucleobases in size and hydrogen-bonding patterns. Isomorphic and expanded FNAs are the two groups that best meet the criteria of non-perturbing fluorescent labels for DNA and RNA. Read More

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evidences on filarial cystatin as a putative ligand of human TLR4.

J Biomol Struct Dyn 2021 May 6:1-17. Epub 2021 May 6.

Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, West Bengal, India.

Cystatin is a small molecular weight immunomodulatory protein of filarial parasite that plays a pivotal role in downregulating the host immune response to prolong the survival of the parasite inside the host body. Hitherto, this protein is familiar as an inhibitor of human proteases. However, growing evidences on the role of cystatin in regulating inflammatory homeostasis prompted us to investigate the molecular reasons behind the explicit anti-inflammatory trait of this protein. Read More

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Identification of a novel inhibitor of SARS-CoV-2 3CL-PRO through virtual screening and molecular dynamics simulation.

PeerJ 2021 13;9:e11261. Epub 2021 Apr 13.

Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh.

Background: The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has ravaged lives across the globe since December 2019, and new cases are still on the rise. Peoples' ongoing sufferings trigger scientists to develop safe and effective remedies to treat this deadly viral disease. While repurposing the existing FDA-approved drugs remains in the front line, exploring drug candidates from synthetic and natural compounds is also a viable alternative. Read More

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Synthesis and crystal structure of -poly[[tetra-μ-acetato-copper(II)]-μ-6-eth-oxy-,-bis-[2-(pyridin-2-yl)eth-yl]-1,3,5-triazine-2,4-di-amine].

Acta Crystallogr E Crystallogr Commun 2021 Mar 26;77(Pt 3):319-323. Epub 2021 Feb 26.

Department of Chemistry, Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA.

The title compound, [Cu(CHNO)(CHO)] , was obtained reaction of copper(II) acetate with the coordinating ligand, 6-eth-oxy-,-bis-[2-(pyridin-2-yl)eth-yl]-1,3,5-triazine-2,4-di-amine. The crystallized product adopts the monoclinic 2/ space group. The metal core exhibits a paddle-wheel structure typical for dicopper tetra-acetate units, with triazine and pyridyl nitro-gen atoms from different ligands coordinating to the two axial positions of the paddle wheel in an asymmetric manner. Read More

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Di--but-yl['-(3-meth-oxy-2-oxidobenzyl-idene)--phenyl-carbamohydrazono-thio-ato]tin(IV): crystal structure, Hirshfeld surface analysis and computational study.

Acta Crystallogr E Crystallogr Commun 2021 Mar 23;77(Pt 3):286-293. Epub 2021 Feb 23.

Research Centre for Crystalline Materials, School of Medical and Life Sciences, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.

The title diorganotin Schiff base derivative, [Sn(CH)(CHNOS)], features a penta-coordinated tin centre defined by the N,,-donor atoms of the di-anionic Schiff base ligand and two methyl-ene-C atoms of the -butyl substituents. The resultant CNOS donor set defines a geometry inter-mediate between trigonal-bipyramidal and square-pyramidal. In the crystal, amine-N-H⋯O(meth-oxy) hydrogen bonding is found in a helical, supra-molecular chain propagating along the -axis direction. Read More

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Threefold helical assembly hy-droxy hydrogen bonds: the 2:1 co-crystal of bi-cyclo-[3.3.0]octane--3,-7-diol and bi-cyclo-[3.3.0]octane--3,-7-diol.

Acta Crystallogr E Crystallogr Commun 2021 Mar 19;77(Pt 3):270-276. Epub 2021 Feb 19.

School of Chemistry, University of New South Wales, UNSW Sydney NSW 2052, Australia.

Reduction of bi-cyclo-[3.3.0]octane-3,7-dione yields a mixture of the -3,-7-diol and -3, -7-diol (CHO) isomers ( and ). Read More

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Crystal structure of a methanol solvate of a macrocycle bearing two flexible side-arms.

Acta Crystallogr E Crystallogr Commun 2021 Mar 5;77(Pt 3):233-236. Epub 2021 Feb 5.

Technische Universität Bergakademie Freiberg, Leipziger Str. 29, D-09596 Freiberg/Sachsen, Germany.

Di--butyl ,'-{[13,15,28,30,31,33-hexa-ethyl-3,10,18,25,32,34-hexa-aza-penta-cyclo-[25.3.1. Read More

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Crystal structure of -(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ)bis-(thio-cyanato-κ)chromium(III) bromide from synchrotron X-ray diffraction data.

Acta Crystallogr E Crystallogr Commun 2021 Mar 2;77(Pt 3):222-225. Epub 2021 Feb 2.

Department of Chemistry, Andong National University, Andong 36729, Republic of Korea.

The crystal structure of the title complex, -[Cr(NCS)(cyclam)]Br (cyclam = 1,4,8,11-tetra-aza-cyclo-tetra-decane, CHN), has been determined from synchrotron X-ray data. The asymmetric unit contains one [Cr(NCS)(cyclam)] cation and one bromide anion. The Cr ion of the complex cation is coordinated by the four N atoms of the cyclam ligand and by two N-coordinating NCS groups in a arrangement, displaying a distorted octa-hedral coordination sphere. Read More

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Unveiling the self-association and desolvation in crystal nucleation.

IUCrJ 2021 May 30;8(Pt 3):468-479. Epub 2021 Apr 30.

National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin university, Tianjin 300072, People's Republic of China.

As the first step in the crystallization process, nucleation has been studied by many researchers. In this work, phenacetin (PHEN) was selected as a model compound to investigate the relationship between the solvent and nucleation kinetics. Induction times at different supersaturation in six solvents were measured. Read More

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Supramolecular structures of Ni and Cu with the sterically demanding Schiff base dyes driven by cooperative action of preagostic and other non-covalent interactions.

IUCrJ 2021 May 1;8(Pt 3):351-361. Epub 2021 May 1.

University of Tyumen, Volodarskogo Street 6, Tyumen, 625003, Russian Federation.

This work reports on synthesis and extensive experimental and theoretical investigations on photophysical, structural and thermal properties of the Ni and Cu discrete mononuclear homoleptic complexes [Ni()] and [Cu()] fabricated from the Schiff base dyes -HOCH-CH=N--CH (H) and -HOCH-CH=N--CH (H), containing the sterically crowding cyclo-hexyl units. The six-membered metallocycles adopt a clearly defined envelope conformation in [Ni()], while they are much more planar in the structures of [Ni()] and [Cu()]. It has been demonstrated by in-depth bonding analyses based on the ETS-NOCV and Interacting Quantum Atoms energy-decomposition schemes that application of the bulky substituents, containing several C-H groups, has led to the formation of a set of classical and unintuitive intra- and inter-molecular interactions. Read More

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Interactions and effects of food additive dye Allura red on pepsin structure and protease activity; experimental and computational supports.

Res Pharm Sci 2021 Feb 30;16(1):58-70. Epub 2020 Dec 30.

Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, I.R. Iran.

Background And Purpose: Today, color additives such as Allura red (AR) are widely used in different kinds of food products. Pepsin is a globular protein that is secreted as a digestive protease from the main cells in the stomach. Because of the important role of pepsin in protein digestion and because of its importance in digestive diseases the study of the interactions of pepsin with chemical food additives is important. Read More

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February 2021

Enantioselective, Catalytic Multicomponent Synthesis of Homoallylic Amines Enabled by Hydrogen-Bonding and Dispersive Interactions.

J Am Chem Soc 2021 May 5. Epub 2021 May 5.

Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.

We report a one-step catalytic, enantioselective method for the preparation of homoallylic -Boc amines directly from acetals. Reactive iminium ion intermediates are generated through the combination of an acetal, a chiral thiourea catalyst, trialkylsilyl triflate, and -Boc carbamate and are subsequently trapped by a variety of allylsilane nucleophiles. No homoallylic ether byproducts are detected, consistent with allylation of the iminium intermediate being highly favored over allylation of the intermediate oxocarbenium ion. Read More

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Ionic framework constructed with protic ionic liquid units for improving ammonia uptake.

Chem Commun (Camb) 2021 May;57(36):4384-4387

College of Materials Science and Engineering, Huaqiao University, Xiamen 361021, P. R. China.

In this work, an ionic framework [Ph3ImH][Tf2N]2 constructed from protic imidazolium ionic liquid units through ionic and hydrogen bonding interactions was synthesized for selective ammonia uptake. Investigation of the NH3 uptake mechanism indicates that the acid sites in [Ph3ImH][Tf2N]2 would be frustrated when contacted with NH3, and the frustration of [Ph3ImH][Tf2N]2 precipitates NH3 capture by hydrogen bonding and physical interactions, and the NH3 could be released under mild conditions. There was no obvious decrease in capacity over 10 consecutive cycles of ammonia uptake and release. Read More

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Structural diversity among some dialkyltin(IV) benzoate and related derivatives.

Acta Crystallogr C Struct Chem 2021 05 9;77(Pt 5):209-220. Epub 2021 Apr 9.

Centre for Advanced Studies in Chemistry, North-Eastern Hill University, NEHU Permanent Campus, Umshing, Shillong 793 022, India.

The molecular structures of five diorganotin(IV) carboxylates, (I)-(V), can be categorized into two main well-known structural types for such Sn complexes. One is the mononuclear dialkytin(IV) carboxylates with an [RSn(LH)]-type skew-trapezoidal bipyramid, where the alkyl ligands are in pseudo-axial positions and the O atoms from two asymmetrically coordinated bidentate carboxylate ligands are in the equatorial plane. This structure type is adopted by dibutylbis{(E)-2-hydroxy-5-[(3-methylphenyl)diazenyl]benzoato}tin(IV) cyclohexane hemisolvate, [Sn(CH)(CHNO)]·0. Read More

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Interaction study of astilbin, isoastilbin and neoastilbin toward CYP2D6 by multi-spectroscopy and molecular docking.

Luminescence 2021 May 4. Epub 2021 May 4.

The College of Chemistry, Changchun Normal University, Changchun, China.

Astilbin, isoastilbin and neoastilbin are the three flavonoid isomers prevalent in Rhizoma Smilax glabra (S. glabra). The interactions between human cytochrome P450 2D6 (CYP2D6) and the three isomers were investigated by multiple spectroscopic coupled with molecular docking. Read More

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Facile preparation of solid dispersions by dissolving drugs in N-vinyl-2-pyrrolidone and photopolymerization.

Mater Sci Eng C Mater Biol Appl 2021 May 26;124:112063. Epub 2021 Mar 26.

Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, China; Pharmaceutical College of Henan University, Kaifeng 475004, China; Shenyang Pharmaceutical University, Shenyang 110016, China. Electronic address:

Drug solid dispersions improve the dissolution of drugs in aqueous media for enhancement of oral bioavailability. The current preparation methods of drug solid dispersions mainly involve the evaporation of solvents or the melting of drugs and matrix. Here, we create a new and simple method for the preparation of drug solid dispersions by dissolving drugs in N-vinyl-2-pyrrolidone (NVP) and then NVP photopolymerization. Read More

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Focal Point Evaluation of Energies for Tautomers and Isomers for 3-Hydroxy-2-Butenamide: Evaluation of Competing Internal Hydrogen Bonds of Types -OH…O=, -OH…N, -NH…O=, and CH…X (X=O and N).

Molecules 2021 Apr 30;26(9). Epub 2021 Apr 30.

Chemistry Department, University of Virginia, Charlottesville, VA 22902, USA.

The title compound is a small molecule with many structural variations; it can illustrate a variety of internal hydrogen bonds, among other noncovalent interactions. Here we examine structures displaying hydrogen bonding between carbonyl oxygen and hydroxyl H; between carbonyl oxygen and amino H; hydroxyl H and amino N; hydroxyl O and amino H. We also consider H-bonding in its tautomer 2-oxopropanamide. Read More

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Binding mechanism and functional evaluation of quercetin 3-rhamnoside on lipase.

Food Chem 2021 Apr 28;359:129960. Epub 2021 Apr 28.

College of Chemical Engineering, Sichuan University, Chengdu 610010, China.

The interaction between lipase and quercetin 3-rhamnoside was studied by fluorescence spectroscopy, enzyme kinetics, and molecular dynamics simulation. The results showed that quercetin 3-rhamnoside had a strong quenching effect on the intrinsic fluorescence of lipase. The binding constant decreased with increasing temperature, and the number of binding sites approached 1. Read More

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Heterogeneous Interactions of Prevalent Indoor Oxygenated Organic Compounds on Hydroxylated SiO Surfaces.

Environ Sci Technol 2021 May 4. Epub 2021 May 4.

Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States.

Oxygenated organic compounds (OOCs) are widely found in indoor environments and come from either the direct emissions from indoor activities or the subsequent oxidation of nonoxygenated OCs. Adsorption and partitioning of OCs on surfaces are significant processes in indoor chemistry, yet these interactions specifically involving OOCs are still poorly understood. In this study, we investigate the interactions of three prevalent indoor OOCs (dihydromyrcenol, α-terpineol, and linalool) on an indoor surface proxy (hydroxylated SiO) by combining vibrational spectroscopy with molecular dynamics simulations. Read More

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Highly Efficient Activatable MRI Probe to Sense Myeloperoxidase Activity.

J Med Chem 2021 May 4. Epub 2021 May 4.

Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States.

Myeloperoxidase (MPO) is a key component of innate immunity but can damage tissues when secreted abnormally. We developed a new generation of a highly efficient MPO-activatable MRI probe (heMAMP) to report MPO activity. heMAMP has improved Gd stability compared to bis-5-HT-Gd-DTPA (MPO-Gd) and demonstrates no significant cytotoxicity. Read More

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Nucleocapsid protein preferentially binds the stem-loop of duplex/quadruplex hybrid that unfolds the quadruplex structure.

Chem Commun (Camb) 2021 May 4. Epub 2021 May 4.

Department of Pharmacy, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230001, China.

NCp7 protein binds the duplex/quadruplex hybrid structure, which decreases the thermal stability of DNA and unfolds the G-quadruplex structure. Interestingly, the duplex in the stem-loop region is the more favorable binding site of NCp7. The NCp7 binding twists the top G-tetrad, weakens hydrogen bonding and causes K+ ejection, hence disrupting the G4 structure. Read More

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Unveiling the phase behavior of CE non-ionic surfactants in water through coarse-grained molecular dynamics simulations.

Soft Matter 2021 May 4. Epub 2021 May 4.

CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-1933, Aveiro, Portugal.

Poly(oxyethylene) alkyl ethers, usually denoted by CiEj surfactants, exhibit a rich phase behavior in water, self-assembling to form a variety of 3-D structures with a controllable morphology that find multiple applications across different industrial segments. Hence, being able to describe and understand the effect of molecular structure on the phase behavior of these systems is highly relevant for the efficient design of new materials and their applications. Considering the promising results obtained over the last decade using the MARTINI model to describe ethylene-oxide containing compounds, an extensive assessment of the ability of such a model to describe the phase behavior of CiEj in water was carried out and results are presented here. Read More

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Single crystals of mechanically entwined helical covalent polymers.

Nat Chem 2021 May 3. Epub 2021 May 3.

Department of Chemistry, University of Colorado Boulder, Boulder, CO, USA.

Double helical conformation of polymer chains is widely observed in biomacromolecules and plays an essential role in exerting their biological functions, such as molecular recognition and information storage. It has remained challenging, however, to prepare synthetic helical polymers, and those that exist have mainly been limited to single-stranded polymers or short oligomeric double helices. Here, we report the synthesis of covalent helical polymers, with a high molecular weight, from the achiral monomer hexahydroxytriphenylene through to spiroborate formation. Read More

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Biochar-mediated reduction of m-nitrotoluene: Interaction between reduction of m-nitrotoluene and sequestration of contaminants.

Sci Total Environ 2021 Jun 8;773:145662. Epub 2021 Feb 8.

College of geographical Science, Ministry of Education Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Provincial Key Laboratory for Plant Eco-Physiology, Fujian Normal University, Fuzhou, Fujian 350007, China.

Biochar is a highly effective adsorbent for nitroaromatic compounds (NACs), and acts as an electron shuttle that mediates the reduction of NACs. Hence, when biochar is used to mediate NAC reduction, adsorption and reduction will occur simultaneously and affect each other. However, the effect of biochar-mediated NAC reduction on sorption remains unknown. Read More

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Frequency Shift Surface-Enhanced Raman Spectroscopy Sensing: An Ultrasensitive Multiplex Assay for Biomarkers in Human Health.

ACS Sens 2021 May 3. Epub 2021 May 3.

CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, the Chinese Academy of Sciences, Beijing 100049, China.

The sensitive and selective detection of biomarkers for human health remains one of the grand challenges of the analytical sciences. Compared to established methods (colorimetric, (chemi) luminescent), surface-enhanced Raman spectroscopy (SERS) is an emerging alternative with enormous potential for ultrasensitive biological detection. Indeed even attomolar (10 M) detection limits are possible for SERS due to an orders-of-magnitude boosting of Raman signals at the surface of metallic nanostructures by surface plasmons. Read More

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First-Principles Simulations of CuCl in High-Temperature Water Vapor.

J Phys Chem B 2021 May 3. Epub 2021 May 3.

Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.

Experimental data suggest that the solubility of copper in high-temperature water vapor is controlled by the formation of hydrated clusters of the form CuCl(HO), where the average number of water molecules in the cluster generally increases with increasing density [Migdisov, A. A.; et al. Read More

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