XAS study on electron transfer in cobalt complexes containing catecholate and semiquinone ligands

Abstract

XAFS measurements have been carried out at both room temperature and 100 K on complexes of general form of CoIII(N-N)(DBQ), where N-N is 1,l0-phenanthroline(phen), N,N,N'N'-tetramethylethlenediammine(tmeda), and DBQ is the 3,6- di-tert-butylcatechol or 3,6-di-tert-semiquinone ligands. Co K-edge XAFS spectra disclosed that Co(tmeda)(DBQ)2 is locked in a charge distribution of CoIII(tmeda)(3,6-DBSQ)(3,6-DBCat), while Co(phen)(DBQ)2 is accompanied by the transition of CoIII/CoIII dependent on temperature.