Electron spin resonance study of solute-solute interactions in aqueous solutions containing transition metal ion chelates of 4, 4′, 4″, 4‴-tetrasulphophthalocyanine

Abstract

The e.s.r. spectra of frozen aqueous-dimethylformamide (dmf) solutions containing binary mixtures of cobalt(II) tetrasulphophthalocyanine (tspc), nickel(II)tspc, copper(II)tspc and zinc tspc have been used to discern various solute–solute interactions. Addition of zinc tspc or nickel(II) tspc to an aqueous solution containing copper(II) tspc has a profound influence on the ability of dmf to bring about the disaggeregation of the copper(II)tspc. The presence of zinc tspc results in a stabilization of the polymeric form of copper(II) tspc while nickel(II) tspc brings about a breakdown of the aggregated form of copper(II)tspc by addition of dmf. There is unambiguous evidence for the formation of a molecular species containing both nickel(II) tspc and cobalt(II) tspc. The e.s.r. spectra of an aqueous–dmf solution containing copper(II) tspc and cobalt(II) tspc provide evidence for the formation of a species in which dissimilar ion coupling occurs between copper(II) and cobalt(II). Spectra due to cobalt(II) tspc were interpreted by an axial model which did not require the inclusion of quadrupole effects.