Synthesis and Intramolecular Electron-Transfer Reaction of Distance-Fixed Quinone-Linked Porphyrins

Abstract Synthesis is described of a series of distance-fixed quinone-linked porphyrins in which electron affinity of the attached quinone is systematically changed. The fluorescence lifetimes of the porphyrin chromophore in these model compounds were shortened due to the intramolecular electron transfer to the attached quinone. The rates of the charge separation between the singlet excited state of the porphyrin and the quinone were determined on the basis of these shortened fluorescence lifetimes and were plotted against the free energy changes associated with the charge separation. Up to ca. 1.54 eV exothermic reaction, the rates of the charge separation were found to still increase.