PHOTOCHEMICAL AND PHOTOPHYSICAL PROCESSES IN FAC-RE(CO)(3)-(4-PHENYLPYRIDINE)(3)(CF3SO3) - STEADY-STATE AND FLASH-PHOTOLYSIS STUDY

The photophysics and photochemistry of fac-Re(CO)(3)(4-phenylpyridine) (3)(+) were investigated by monochromatic steady state and flash photo lysis. Two parallel photoprocesses, photogeneration of the emissive me tal-to-ligand charge transfer (MLCT) state and photoredox dissociation in [Re(CO)(3)(4-phenylpyridine)(2)(2+), (4-phenylpyridine(-))], were observed. In the former process, the emission originating from the low er MLCT excited state is electron transfer quenched by triethanolamine (TEOA) producing an Re(CO)(3)(4-phenylpyridine)(3)(.) radical and ene rgy transfer quenched by Cu(TIM)(2+) (TIM = 2,3,9,10-tetramethyl-[14]- 1,4,8,11-tetraene-N-4). The primary species Re(CO)(3)(4-phenylpyridine )(2)(2+) generated in the latter photoprocess undergoes several therma l changes which finally lead to dimeric products. A third photoprocess , namely the photogeneration of the [Re(CO)(3)(4-phenylpyridine)(2)(2) (4-phenylpyridine(-))] species, is involved in the reduction of the copper macrocycle to Cu(TIM)(+).