Synthesis, characterization and X-ray crystal structures of ruthenium polypyridyl and 2-(2′-hydroxyphenyl)-benzoxazole complexes: Reactivity with 1-methylimidazole, purine, glutathione and CT-DNA

Ruthenium complexes containing terpyridine or the 4'-substituted terpyridines and 2-(hydroxyphenyl)-benzoxazole (HPB) have been synthesized and characterized. The crystal structures of three of the complexes have been determined. All three complexes, trans-[Ru(tolylterpy)(HPB)(Cl)](PF6), cis-[Ru(toly-Iterpy)(HPB)(H2O)](PF6)(2) and cis-[Ru(terpy)(HPB)(NMI)](PF6) show a distorted octahedral geometry around the ruthenium center. The influence of the positional coordination of the phenolic oxygen of the HPB ligand on the spectrophotometric properties and the E-1/2 values of the complexes have been observed. The reaction of the aqua complexes with 1-methylimidazole (NMI), glutathione (GSH), purine and CT-DNA have been studied. Activation parameters for the reaction of 1-methylimidazole, glutathione and purine suggest that the substitution of the aqua ligand follow an associative mechanism. Spectrophotometric studies of the reactivity between CT-DNA and the aqua complexes indicate an interaction between the CT-DNA and the aqua complex. Published by Elsevier Ltd.