Biomimetic model of coenzyme B-12: Aquabis(ethane-1,2-diamine-kappa N,kappa N ')ethylcobalt(III) - Its kinetic and binding studies with Imidazoles and amino acids and interactions with CT DNA

Pseudo-first-order reaction kinetics and binding studies of trans-[Co(en)(2)(Et)H2O] complex with 1H-imidazole, substituted 1H-imidazoles, histidine, histamine, glycine and glycine ethyl ester were investigated by means of spectrophotometric techniques. Equilibrium constants were determined as a function of pH at 25 degrees. Binding and kinetic studies were correlated to basicity and steric hindrance. From the equilibrium data, it was found that the entering nucleophile is participating in the transition state, an I-d mechanism is proposed. The effect of the incoming ligands on the complex was studied by molecular mechanics. The interaction of trans-[Co(en)(2)(Et)H2O] with CT DNA was studied spectrophotometrically.