CHARGE-TRANSFER PROCESSES IN (4-NITROBENZOATE)RE(CO)(3)(AZINE)(2) COMPLEXES - COMPETITIVE REDUCTIONS OF 4-NITROBENZOATE AND AZINE IN THERMALLY AND PHOTOCHEMICALLY INDUCED REDOX PROCESSES

The photochemically and thermally induced redox reactions of the (4-ni trobenzoate)Re(CO)(3) (azine) (azine = 1,10-phenanthroline, 2,2'-bipyr idine, and (4-phenylpyridine)(2)) were investigated by flash photolysi s and pulse radiolysis. Processes characterized as intramolecular char ge transfers from coordinated azine radicals to the 4-nitrobenzoate li gand and vice versa were observed in a 1-100 mu s time scale by pulse radiolysis. In photochemical experiments, the conversion among metal t o Ligand charge-transfer excited states, i.e., from the Re to azine to the Re to 4-nitrobenzoate charge-transfer excited stale, involves int ermediates with Lives of picoseconds. A mechanism for the conversions that incorporates intraligand excited states is discussed.