Local stretching force constants derived from periodic local vibrational modes at the vdW-DF2 density functional level have been employed to quantify the intrinsic hydrogen bond strength of 16 ice polymorphs, ices I, II, III, IV, V, VI, VII, VIII, IX, XI, XII, XIII, XIV, XV, XVII, and XIX, that are stable under ambient to elevated pressures. Based on this characterization on 1820 hydrogen bonds, relationships between local stretching force constants and structural parameters such as hydrogen bond length and angle were identified. Moreover, different bond strength distributions, from uniform to inhomogeneous, were observed for the 16 ices and could be explained in relation to different local structural elements within ices, that is, rings, that consist of different hydrogen bond types. In addition, criteria for the classification of hydrogen bonds as strong, intermediate, and weak were introduced. The latter was used to explore a different dimension of the water-ice phase diagram. These findings will provide important guidelines for assessing the credibility of new ice structures.
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http://dx.doi.org/10.1021/acs.jctc.1c00357 | DOI Listing |
Euroasian J Hepatogastroenterol
December 2024
Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Ehime, Japan.
Objectives: To predict and characterize the three-dimensional (3D) structure of protein arginine methyltransferase 2 (PRMT2) using homology modeling, besides, the identification of potent inhibitors for enhanced comprehension of the biological function of this protein arginine methyltransferase (PRMT) family protein in carcinogenesis.
Materials And Methods: An method was employed to predict and characterize the three-dimensional structure. The bulk of PRMTs in the PDB shares just a structurally conserved catalytic core domain.
Chem Sci
January 2025
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology (SCUT) Guangzhou 510640 China.
Radical-mediated dearomatization strategies offer a blueprint for building value-added and synthetically valuable three-dimensional skeletons from readily available aromatic starting materials. Herein, we report a novel strategy by leveraging benzene-linked O-oxime esters as triply functionalized precursors to form two distinct persistent radicals under a chemodivergent pathway. These radicals then couple with a cyclohexadienyl radical for either carboamination or carbo-aminoalkylation.
View Article and Find Full Text PDFACS Mater Au
January 2025
Department of Electrical and Electronic Engineering, Kyushu Institute of Technology, 1-1 Sensuicho, Tobataku, Kitakyushu, Fukuoka 804-8550, Japan.
Ionic gels (IGs), ionic liquids (ILs) dispersed in polymers, exhibit extremely low vapor pressure, electrochemical and thermal stability, and excellent mechanical characteristics; therefore, they are used for fabricating stretchable sensors, electrochemical transistors, and energy storage devices. Although such characteristics are promising for flexible and stretchable electronics, the mechanical stress-induced ruptured covalent bonds forming polymer networks cannot recover owing to the irreversible interaction between the bonds. Physical cross-linking via noncovalent bonds enables the interaction of polymers and ILs to form supramolecular IGs (SIGs), which exhibit favorable characteristics for wearable devices that conventional IGs with noncovalent bonds cannot achieve.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
Carbonless DNA was designed by replacing all carbon atoms in the standard DNA building blocks with boron and nitrogen, ensuring isoelectronicity. Electronic structure quantum chemistry methods (DFT(ωB97XD)/aug-cc-pVDZ) were employed to study both the individual building blocks and the larger carbon-free DNA fragments. The reliability of the results was validated by comparing selected structures and binding energies using more accurate methods such as MP2, CCSD, and SAPT2+3(CCD)δ.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan.
We studied the vibrational coherences during the ultrafast internal conversions (ICs) of pyrimidine nucleobases and -sides in aqueous solutions and the gas phase with an instrumental resolution of 14 fs. The coherence of the same ring-breathing vibrational mode with a frequency of 750 cm was observed. In the gas phase, the vibrational coherence was transferred during IC from the ππ* to the nπ* state, and it survived for approximately 1 ps.
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