Interaction of the univalent silver cation with [Gly6]-antamanide: Experimental and theoretical study

Autor: Jaroslav Kvíčala, Petr Vaňura, Stanislav Böhm, Paolo Ruzza, Emanuel Makrlík
Rok vydání: 2018
Předmět:
Zdroj: Journal of molecular structure
1155 (2018): 807–812. doi:10.1016/j.molstruc.2017.11.059
info:cnr-pdr/source/autori:Makrlik, Emanuel; Boehm, Stanislav; Kvicala, Jaroslav; Vanura, Petr; Ruzza, Paolo/titolo:Interaction of the univalent silver cation with [Gly(6)]-antamanide: Experimental and theoretical study/doi:10.1016%2Fj.molstruc.2017.11.059/rivista:Journal of molecular structure (Print)/anno:2018/pagina_da:807/pagina_a:812/intervallo_pagine:807–812/volume:1155
ISSN: 0022-2860
DOI: 10.1016/j.molstruc.2017.11.059
Popis: On the basis of extraction experiments and gamma-activity measurements, the extraction constant corresponding to the equilibrium Ag+(aq) + 1 center dot Na+(nb) reversible arrow 1 center dot Ag+ (nb) + Na+(aq) occurring in the two phase water nitrobenzene system (1 = [Gly(6)]-antamanide; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (Ag+,1 center dot Na+) = 1.5 +/- 0.1. Further, the stability constant of the 1 center dot Ag+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 degrees C: log beta(nb) (1 center dot Ag+) = 4.5 +/- 0.2. Finally, by using quantum chemical OFF calculations, the most probable structure of the cationic complex species 1 center dot Ag+ was derived. In the resulting complex, the "central" cation Ag+ is coordinated by four noncovalent interactions to the corresponding four carbonyl oxygen atoms of the parent ligand 1. Besides, the whole l center dot Ag+ complex structure is stabilized by two intramolecular hydrogen bonds. The interaction energy of the considered 1 center dot Ag+ complex was found to be -465.5 kJ/mol, confirming also the formation of this cationic species. (C) 2017 Elsevier B.V. All rights reserved.
Databáze: OpenAIRE