Intramolecular photochemical electron transfer. 6. Bridge and solvent dependence of electron transfer in covalently linked porphyrin-peptide-quinone compounds

Intramolecular electron transfer (ET) rate constants k{sub ET} for three covalently linked porphyrin-peptide-quinone compounds have been measured in several solvents. The results show that not only through-bridge, but also through-solvent interactions play important roles in the intramolecular ET process. This latter effect is deduced from the observation that aromatic groups, as both side groups in the bridge and in the solvent, appear to induce a significant increase in the ET rate.