Mutual Influence of Ligands and Reactivity of Gd and Dy Acidophthalocyaninate Complexes

The results of the kinetic study of dissociation of Gd(III) and Dy(III) complexes with phthalocyanine of the composition (X)LnPc (X is single-charged acido ligand) with isolation of macrocyclic ligand depending on the temperature, composition of mixed ethanol–acetic acid solvent, and the nature of acido ligand are presented. The total kinetic equations, the rate constants, and activation parameters of dissociation reaction are determined. The stoichiomeric mechanism is suggested for the complex dissociation involving the limiting elementary reaction between acetic acid molecule and the complex that occurs as the chelate salt (X)LnPc or the outer-sphere complex [(HOAc)LnPс]+X–. The state of metal phthalocyaninate at the reaction slow stage is shown to be determined by the electronic structure of the metal cation, the strength of binding of the axial ligand, and by its cis-effect on the metal bonds with macrocycle.