Photochemical and photophysical properties of fac-[Re(CO)3(L)2Cl](L = quinoline or isoquinoline)

Abstract

Two new complexes, fac-[Re(CO)₃(L)₂Cl](L = quinoline or isoquinoline), have been prepared and characterized by X-ray crystallography and spectroscopies. Extended-Hückel molecular orbital calculations were applied to the interpretation UV/VIS spectra of the complexes. Their photochemical and photophysical properties were investigated under steady and flash irradiations. While room-temperature luminescence appears strongly related to the metal-to-ligand charge-transfer excited states, the radiative relaxation of the intraligand excited states dominates the 77 K emissions. The photochemical reactions of fac-[Re(CO)₃(L)₂Cl](L = quinoline or isoquinoline) are similar to those of fac-[Re(CO)₃(4Ph-py)₂Cl](4Ph-py = 4-phenylpyridine) and expected to originate in intraligand and/or ligand-to-ligand charge-transfer excited states.