Selective and Effective Stabilization of MoVI═O Bonds by NH···S Hydrogen Bonds via Trans Influence
摘要:
A monooxomolybdenum(IV) complex containing two intramolecular NH center dot center dot center dot S hydrogen bonds, (NEt4)(2)[(MoO)-O-IV-(1,2-S-2-3-t-BuNHCOC6H3)(2)], was synthesized. The trans isomer was crystallized as the major product, and the molecular structure was determined by X-ray analysis. The trans isomer was isomerized by heating in solution to give a 1:1 mixture of trans and cis isomers. Oxidation of these isomers by Me3NO afforded (NEt4)(2)[(MoO2)-O-VI(1,2-S-2-3-t-BuNHCOC6H3)(2)]. H-1 NMR analysis revealed that the dioxomolybdenum(VI) complex existed as a single isomer where both oxo ligands were trans to each of the two hydrogen-bonded thiolate ligands. The Mo-VI=O bond was effectively stabilized by the NH center dot center dot center dot S hydrogen bond via trans influence, which was determined using resonance Raman spectroscopy. These results were supported by preliminary density functional theory calculations.
Monooxomolybdenum(IV) and dioxomolybdenum(VI) benzenedithiolate derivatives containing anilide moieties were synthesized and characterized by 1H NMR, UV-visible, IR, and Raman spectroscopies. These complexes exhibit very strong intramolecular NHâ¯S hydrogen bonds formed by the acidic anilide NH proton and the desired coplanar structure, resulting in significantly positive redox potential and remarkable acceleration in the reduction of Me3NO in DMF.
Carboxy‐thioether‐thiolato titanium–graphene oxide nanocomposite as drug delivery system for targeted cancer therapy: Design, characterization, bovine serum albumin binding study, and biological evaluation
作者:Hanan A. Mohamed、Mohamed M. Ibrahim、Ibrahim M. El‐Mehasseb、Abd El‐Motaleb M. Ramadan、Shaban Y. Shaban
DOI:10.1002/aoc.7009
日期:2023.3
investigate the interactions of CTT, TiCTT, GO, and GO–TiCTT nanocomposite with bovineserumalbumin (BSA). The results revealed that the intrinsic fluorescence quenching of BSA resulting from low concentrations was caused by the formation of stable BSA adducts via the binding interaction with BSA. The stable adduct had a stoichiometry of 1:1 and binding constants (Kb) in the order of 105 M1 at 310 K for CTT
Synthesis, structure and DFT calculation of a hexanuclear mixed-valence copper cluster supported by 2,3-disulfidobenzoate and 3-carboxybenzene-1,2-bis(thiolate)
作者:Kuntal Pal、Satoshi Takamizawa、Kazushi Mashima
DOI:10.1016/j.ica.2011.03.055
日期:2011.7
A homoleptic hexanuclear Cu cluster, [(Cu(DSB)(CBT))(2)(Cu2Br)(2)][PPh4](2) (1-PPh4) [DSB = 2,3-disulfidobenzoate; CBT = 3-carboxybenzene-1,2-bis(thiolate)] was synthesized as dark green crystals by the reaction of CuCl2 with 2,3-dimercaptobenzoic acid in acetate buffer solution. The X-ray crystal study of 1-PPh4 revealed its unique structural features: (1) one of two types of crystallographically distinct Cu centers adopted a square planer geometry and the other center had a tetrahedral geometry, and (2) intermolecular H-bonding interactions connected between carboxylic acid group of CBT and the carboxylate group of DSB led to the construction of an unprecedented topologic architecture of a zigzag patterned infinite sheet. In addition, taking into account the total charge of the molecule, which contained 2,3-disulfidobenzoate and 3-carboxybenzene-1,2-bis(thiolate), and the diamagnetic nature of 1-PPh4, 1-PPh4 led to it is assignment as a mixed-valence Cu(I)/Cu(III) cluster. Such mixed valence states of Cu atoms were also examined by density functional theory calculation. (C) 2011 Elsevier B.V. All rights reserved.
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