edoc

Influence of a Decreasing Solvent Polarity on the Stability and Structure of Mixed-Ligand Complexes Formed by Copper(II), 2,2'-Bipyridine or 1,10-Phenanthroline and Guanosine 5'-Diphosphate

Operschall, B. P. and Bianchi, E. M. and Griesser, R. and Sigel, H.. (2009) Influence of a Decreasing Solvent Polarity on the Stability and Structure of Mixed-Ligand Complexes Formed by Copper(II), 2,2'-Bipyridine or 1,10-Phenanthroline and Guanosine 5'-Diphosphate. Journal of coordination chemistry, Vol. 62, H. 1. pp. 23-39.

Full text not available from this repository.

Official URL: http://edoc.unibas.ch/dok/A6083352

Downloads: Statistics Overview

Abstract

The stability consts. of the 1:1 complexes formed between Cu(Arm) 2+, where Arm = 2,2'-bipyridine or 1,10-phenanthroline, and (GDP)3- or its monoprotonated form H(GDP)2- were detd. by potentiometric pH titrns. in water and in water contg. 30 or 50 vol.% of 1,4-dioxane (25°; I = 0.1 M, NaNO3). The stability of the binary Cu(GDP)- complex is enhanced due to macro-chelate formation of the diphosphate-coordinated Cu2+ with N7 of the guanine residue as previously shown. In Cu(Arm)(GDP)- the N7 is released from Cu2+ and the stability enhancement of more than one log unit in aq. soln. is clearly attributable to intramol. stack formation between the arom. rings of Arm and the guanine moiety. Indeed, stacked isomers occur to more than 90% in equil. with open unstacked forms. Surprisingly, the same formation degrees of the stacks have previously been obsd. for Cu(Arm)(dGMP) complexes, where dGMP2- = 2'-deoxyguanosine 5'-monophosphate, despite the fact that the overall stability of the latter species is by about 2.7 log units lower. In 1,4-dioxane-water mixts. stack formation is drastically reduced, probably due to hydrophobic solvation of the arom. rings by the ethylene bridges of 1,4-dioxane. The relevance of these results regarding biol. systems is indicated.
Faculties and Departments:05 Faculty of Science > Departement Chemie
UniBasel Contributors:Operschall, Bert P. and Griesser, Rolf and Sigel, Helmut
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
ISSN:0095-8972
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:24 May 2013 09:21
Deposited On:24 May 2013 09:00

Repository Staff Only: item control page