Activation of a metal axial ligand bond in aluminum porphyrin by visible light

Irradiation with visible light induced a remarkable effect on the reactivity of a metal-carbon bond in (tetraphenylporphinato)aluminum methyl in the nucleophilic substitution reaction with protic compounds such as phenol. A similar photoacceleration effect was also observed in the reversible ligand exchange of (tetraphenylporphinato)aluminum phenoxide with phenol. As for the former reaction, comparable quantum yields were observed upon irradiation at the Soret band and at the Q-band. 22 refs., 5 figs.