Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Angew Chem Int Ed Engl ; 61(42): e202210671, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-35983847

RESUMO

The {Ru(NO)2 }10 dinitrosylruthenium complex [Ru(NO)2 (PPh3 )2 ] (1) shows photo-induced linkage isomerism (PLI) of a special kind: the two NO ligands switch, on photo-excitation, synchronously from the ground state (GS) with two almost linear RuNO functions to a metastable state (MS) which persists up to 230 K and can be populated to ≈50 %. The MS was experimentally characterised by photo-crystallography, IR spectroscopy and DS-calorimetry as a double-bent variant of the double-linear GS. The experimental results are confirmed by computation which unravels the GS/MS transition as a disrotatory synchronous 50° turn of the two nitrosyl ligands. Although 1 shows the usual redshift of the N-O stretch on bending the MNO unit, there is no increased charge transfer from Ru to NO along the GS-to-MS path. In terms of the effective-oxidation-state (EOS) method, both isomers of 1 and the transition state are Ru-II (NO+ )2 species.


Assuntos
Rutênio , Cristalografia por Raios X , Isomerismo , Ligantes , Óxido Nítrico/química , Rutênio/química
2.
Acta Crystallogr B Struct Sci Cryst Eng Mater ; 75(Pt 4): 750-762, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32830731

RESUMO

In order to comprehend the binding of an important metabolite, hippuric acid, with human serum albumin and to understand its chemical and electronic nature, an experimental charge-density analysis has been carried out using high-resolution diffraction data collected under cryogenic conditions, and all the results have been compared with theoretical findings using the B3LYP/6-311++g(2d,2p) level of theory. The structure displays very strong classical hydrogen bonds as well as other noncovalent interactions, which have been fully characterized using Hirshfeld surface analysis and Bader's quantum theory of atoms in molecules. Contact analysis on the Hirshfeld surfaces shows that the O...H, C...H and C...N intermolecular interactions are enriched and gives their relative strengths. Topological analysis of the electron density shows the charge concentration/depletion of hippuric acid bonds in the crystal structure. Electrostatic parameters such as atomic charges and dipole moments were calculated. The mapping of atomic basins and the calculation of respective charges show the atomic volumes of each atom as well as their charge contributions in the hippuric acid crystal structure. The dipole-moment calculations show that the molecule is very polar in nature. Calculations of the electrostatic potential show that the chain part of the molecule has a higher concentration of negative charge than the ring, which might be instrumental in its strong binding with the polar residues of site II of human serum albumin.


Assuntos
Hipuratos/química , Hipuratos/metabolismo , Albumina Sérica Humana/metabolismo , Sítios de Ligação , Fenômenos Químicos , Cristalização , Cristalografia por Raios X , Elétrons , Humanos , Ligação de Hidrogênio , Modelos Moleculares , Estrutura Molecular , Ligação Proteica , Eletricidade Estática
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA