Porphyrin-fullerene dyads –synthesis and redox/photophysical properties

Three free base porphyrin-fullerene dyads of C-60-PH2R and their zinc complexes C-60-PZnR were synthesized. They were fully characterized by mass spectrometry, nuclear magnetic resonance, infrared spectroscopy, and ultraviolet-visible spectroscopy. Studies on steady-state fluorescence spectroscopy and cyclic voltammetry show that the coordination of the porphyrin moiety with zinc ions leads to an increases in the singlet excited state energies, and decreases in both the HOMO level and the HOMO-LUMO gap. The introduction of the electron-donating groups of -Me or -OMe to the porphyrin core leads to a negative shift in the first oxidation potential, and a further decrease in the HOMO level. Calculation Results show that the coordination of zinc ions lead to a greatly increase in the photoinduced electron transfer constants k(et) and substituents of the porphyrin core also effect on k(et) value.