Stability and mode of coordination complexes formed in the silver(i)/nucleoside systems

Abstract

Complexes of silver(I) with nucleosides (adenosine, cytidine, uridine and thymidine) have been studied using potentiometric, spectral and theoretical methods. Stability constants of the complexes as well as their coordination modes have been determined. Results of the equilibrium studies have provided evidence for the formation of only ML and ML(OH) type complexes. The basicity of nucleosides was found to substantially influence the stability constant of the ML type complexes. Spectral data have allowed us to identify the sites of silver attachment to the nucleoside. Additionally a new silver–adenosine complex of stoichiometry Ag(Ado)(OH) was prepared from aqueous solution at pH close to 6. Its characterization and comparison with complexes formed in solution are described. The structures of complexes formed in solution and in solid state were confirmed through computational calculations (DFT/B3LYP: lanL2DZ theoretical procedure).