Solution and solid studies of some metal complexes with cytosine and its derivatives

Abstract

Stability constants for the binary (1 : 1) complexes of CoII, NiII, CuII, ZnII, CdII, CaII, SrII and BaII with cytosine, cytidine, 5-bromocytosine, 5-azacytosine and 5-fluorocytosine were determined in aqueous solution (Ionic strength, ¼ 0.1 mol dm À3 NaNO 3 ) potentiometrically at 25, 35 and 45 C. Experimental pH titration data were analyzed using the BEST computer program in order to evaluate formation constants of various intermediate species formed in the above binary systems. Enthalpy and entropy changes for the formation of binary complexes were calculated. On the basis of solution studies, efforts were made to prepare the binary complexes with 5-azacytosine ligand. Isolated solid complexes were characterized by different techniques and spectroscopic studies suggested a polymeric nature for the complexes, with OH and 5-azacytosine acting as bridging ligands.

Interaction of Cytidine 5′‐Monophosphate with Au(111): An In Situ Infrared Spectroscopic Study

“…Indeed, it is established from studies on metal complexes of nucleic acid components that this site has a high binding affinity towards many metal cations. [35,[54][55][56][57][58][59][60] Density functional theory computations involving a single gold atom, [12] a gold cluster [13] or a CuA C H T U N G T R E N N U N G (111) surface [17] have all pointed to a significant metal-N3 interaction. In close relation to our system, electrochemical studies of cytosine adsorption on gold electrodes have reached the same conclusions.…”