XPS studies of planar four-coordinate copper(II) and copper(III) complexes

Abstract

X-ray photoelectron spectra of some planar CuS4 copper N,N-dialkyl dithiocarbamate compounds in the formal +2 and +3 oxidation states and the CuO4 complex carbonate, Na2[Cu(CO3)2], have been recorded. Cu(2p3/2) binding energies for the copper(II) dithiocarbamate and carbonate compounds are similar although the `shakeup' satellite structure for the dithiocarbamate compounds is relatively less intense. The modified Auger parameter, a', for the two sets of compounds is also similar but ca. 1-2 eV lower than the value reported for the most Cu(II) compounds. The copper binding and kinetic energy parameters for the Cu(III) compounds have been found to correspond to values found for the Cu(II) compounds with, however, an absence of secondary satellite structure. Differences between the compounds in the two oxidation states are also found in the ligand sulphur 2p binding energies which are ca. 1 eV higher in the Cu(III) compounds.