Isomeric Equilibria in Aqueous Solution Involving Aromatic Ring Stacking in the Sexternary Complexes Formed by the Quaternary cis-(NH3)2Pt(2‘-deoxyguanosine-N7)(dGMP-N7) Complex and the Binary Cu(2,2‘-bipyridine)2+ or Cu(1,10-phenanthroline)2+ Complexes (dGMP2- = 2‘-Deoxyguanosine 5‘-monophosphate)

Autor:	Bernhard Lippert, Helmut Sigel, Bin Song, Marc Sven Lüth
Rok vydání:	2000
Předmět:	Aqueous solution Stereochemistry Phenanthroline Potentiometric titration Stacking Aromaticity 2 2'-Bipyridine Inorganic Chemistry Crystallography chemistry.chemical_compound chemistry Stability constants of complexes Titration Physical and Theoretical Chemistry
Zdroj:	Inorganic Chemistry. 39:1305-1310
ISSN:	1520-510X 0020-1669
DOI:	10.1021/ic9905087
Popis:	To the best of our knowledge, for the first time the stabilities of sexternary complexes are determined by potentiometric pH titrations in aqueous solution at 25 °C and I = 0.1 M (NaNO3). The sexternary complexes form by binding of the binary Cu(Arm)2+ complexes, where Arm = 2,2‘-bipyridine (Bpy) or 1,10-phenanthroline (Phen), to the −PO32- group present in the quaternary cis-(NH3)2Pt(dGuo)(dGMP) complex. It is shown by stability constant comparisons and spectrophotometric measurements (observation of charge-transfer bands for the Phen system) that the [cis-(NH3)2Pt(dGuo)(dGMP)·Cu(Arm)]2+ complexes can fold in such a way that aromatic ring stacking between the aromatic rings of Bpy or Phen and a guanine residue (most probably the one of dGMP2-) becomes possible. The formation degree of the stacks reaches approximately 25 and 50% for the [cis-(NH3)2Pt(dGuo)(dGMP)·Cu(Bpy)]2+ and [cis-(NH3)2Pt(dGuo)(dGMP)·Cu(Phen)]2+ species, respectively. By comparisons with Cu(Arm)(dGMP) complexes, it is shown that the cis...
Databáze:	OpenAIRE
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