An increasing number of observations show that non-classical isomers may play an important role in the formation of fullerenes and their exo- and endo-derivatives. A quantum-mechanical study of all classical isomers of C , C , and C , and all non-classical isomers with at most one square or heptagonal face, was carried out. Calculations at the B3LYP/6-31G* level show that the favored isomers of C , C , and C have closely related structures and suggest plausible inter-conversion and growth pathways among low-energy isomers. Similarity of the favored structures is reinforced by comparison of calculated ring currents induced on faces of these polyhedral cages by radial external magnetic fields, implying patterns of magnetic response similar to those of the stable, isolated-pentagon C molecule. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jcc.24661 | DOI Listing |
ACS Omega
March 2024
College of Medicine and Health Sciences, Department of Biochemistry and Molecular Biology, United Arab Emirates University, AlAin P.O. Box: 15551, United Arab Emirates.
Bioisosterism is strategically used in drug design to enhance the pharmacokinetic and pharmacodynamic properties of therapeutic molecules. The average electron density (AED) tool has been used in several studies to quantify similarities among nonclassical bioisosteres of carboxylic acid. In this study, the AED tool is used to quantify the similarities among nonclassical bioisosteres of an amide group.
View Article and Find Full Text PDFChem Sci
November 2023
Centre for Analysis and Synthesis, Department of Chemistry, Lund University PO Box 124 22100 Lund Sweden
A number of transition metal hydrides reveal intriguing temperature-dependent in their deuterated derivatives and possibly the temperature dependent hydrogen-hydrogen distance ((H-H)) as well. Previously, theoretical studies rationalized and (H-H) changes in such compounds through a "temperature-elastic" structure model with a significant population of vibrational states in an anharmonic potential. Based on the first variable temperature neutron diffraction study of a relevant complex, (-H-POCOP)IrH, observation of its elusive counterpart with longer (H-H), crystallized as an adduct with CFI, and thorough spectroscopic and computational study, we argue that the model involving isomeric species in solution at least in some cases is more relevant.
View Article and Find Full Text PDFPhys Chem Chem Phys
November 2023
Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China.
A toll-like receptor 4/myeloid differentiation factor 2 complex (TLR4/MD2) has been identified as a non-classical opioid receptor capable of recognizing morphine isomers and activating microglia in a non-enantioselective manner. Additionally, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), the major metabolites of morphine, possess similar chemical structures but exhibit distinct effects on TLR4 signaling. However, the specific mechanisms by which morphine isomers and morphine metabolites are recognized by the innate immune receptor TLR4/MD2 are not well understood.
View Article and Find Full Text PDFJ Chem Phys
April 2023
The Key Laboratory of the Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, 92 Wucheng Road, Taiyuan 030006, Shanxi, People's Republic of China.
The design of clusters featuring non-classical planar hypercoordinate atoms (phAs) often depends on the delocalized multicenter bonds involving reactive electron-deficient elements, which both destabilize the clusters and lead to difficulty in achieving the phA arrangement for electronegative elements such as nitrogen due to their preference for localized bonds. In this work, we computationally designed a series of aluminum chalcogenide clusters NAlX (X = S, Se, Te) with a desired planar tetracoordinate nitrogen and meaningfully improved chemical stability, as evidenced by the wide gaps (6.51-7.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
March 2023
Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, United Kingdom.
The syntheses and crystal structures of four hydro-thermally prepared organo-zinc phosphites, . poly[[(2-amino-3-methyl-pyridine)-μ-phospho-nato-zinc] hemihydrate], {[Zn(HPO)(CHN)]·0.5HO} , (I), poly[(2-amino-4-methyl-pyridine)-μ-phospho-nato-zinc], [Zn(HPO)(CHN)] , (II), poly[(2-amino-5-methyl-pyridine)-μ-phospho-nato-zinc], [Zn(HPO)(CHN)] , (III), and poly[bis-(2-amino-4-methyl-pyridinium) [tetra-μ-phospho-nato-trizinc] monohydrate], {(CHN)[Zn(HPO)]·HO} , (IV), are described.
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