An electron spin resonance study of dimer formation by the copper(II) chelates of polyhydroxycarboxylic acids

Abstract

X-Band e.s.r. measurements have been made on the copper(II) complexes of the polyhydroxycarboxylic acids, saccharic, lactobionic, gluconic and mucic at room temperature and 77 K. Dimer formation has been confirmed for the copper(II) complexes of these polyhydroxycarboxylic acids by the observation of ΔM= 2 signals and also ΔM= 1 signals in certain cases. Computer simulation of these signals which arise from dipole–dipole coupling between the copper(II) ions in their dimeric forms, has allowed the determination of the distance between the copper(II) magnetic dipoles. Structures have been proposed which are compatible with these calculated distances. All measurements and postulated structures refer to species formed in solution and frozen solution.