Reactions of water-soluble binuclear tetranitrosyl iron complexes of the μ-S structural type with adenosine triphosphoric acid: kinetics and reaction mechanism

Abstract The reactions of adenosine triphosphoric acid (ATP) with water-soluble binuclear tetranitrosyl iron complexes of the μ-S structural type with functional sulfur-containing ligands (thiosulfate (1) cysteamine (2), and penicillamine (3)) afford products of close structures. The hydrolysis products of the complexes (1–3) in aqueous aerobic solutions are studied by amperometry and mass electrospectrometry. The kinetic regularities of the reactions of the complexes (1–3) with ATP are studied by the spectrofluorimetric method. A generalized kinetic model describing the experimental data of three reactions is proposed for the process. From the qualitative point of view, the reactions of ATP with the studied complexes occur similarly in spite of the difference in the ligands. The rates of particular steps of the process depend on the nature of the ligands. The values determined for the kinetic parameters quantitatively characterize the influence of the ligand nature in complexes 1–3 on the reactivity toward ATP and increase in the order: cysteamine