ESR study on copper(II) macrocyclic polythia complexes

ESR measurements have been made on complexes formed by copper(II) with 12]anS₄, 13]anS₄, iso-14]anS₄, and 18]anS₆; they show intramolecular reduction for the central ion by electron transfer from the donor sulfur atoms, and free cation-radicals are formed in solution. The covalency parameter ² indicates that the copper-sulfur bonds are mainly covalent. The electronic structures are analogous to those of the active centers in copper-bearing blue proteins.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 6, pp. 737–742, November–December, 1989.