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(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.