Charge Transfer Photochemistry of Bis(8-quinolinolato)copper(II) and Bis(8-quinolinethiolato)copper(II) in Aprotic Solvents

Bojana G. Jeliazkova*, Julia K. Panajotova Department of Chemistry, Sofia University, 1, James Bourchier ave, 1126 Sofia, Bulgaria Dedicated to Prof. Hitoshi Ohtaki on the occasion o f his 60th birthday Z. Naturforsch. 50b, 524-528 (1995); received October 17, 1994 Charge Transfer Photochemistry, Bis(8-quinolinolato)Cu(II), Bis(8-quinolinethiolato)Cu(II) The photochemistry of bis(8-quinolinolato)Cu(II), Cu(ox)2, and bis(8-quinolinethiolato)Cu(II), Cu(tox)2, has been studied by continuous photolysis in aprotic solvents. The charge transfer irradiations induce the oxidation of the ligand and the reduction of copper(II) to copper(I). These assignments are supported by EPR data and UV-Vis spectra of the com­ plexes. The photochemical properties of copper(II) complexes are discussed in terms of the population of charge transfer to copper-excited states. Both complexes show solvent-depcndent photochemistry when irradiated in CHC13 and in toluene. The photoproducts of Cu(tox)2 in CHC13 are partially reconverted into the initial complex by thermal reaction, while photo­ reactions of Cu(ox)2 lead to secondary photolytic processes.