Influence of Configuration on Photoinduced Electron-transfer Mechanism in Sulfonyl Amidine Linked Porphyrin-fullerene Dyad

A novel sulfonyl amidine linked porphyrin-fullerene dyad ZnP-H-C-60 was facilely synthesized via a three components one-pot coupling reaction. There are two isomers(Z- and E-) in the dyad solution in low-polarity solvents, such as chloroform and toluene. We found that the photoinduced electron-transfer(PET) process could occur in two isomers, but the electron-transfer mechanism was different from each other. The electron transfer process was mediated by the intramolecular hydrogen-bond in (Z-)ZnP-H-C-60; and in (E-)ZnP-H-C-60, the porphyrin-fullerene exciplex was the precursor of the charge separation(CS) state due to the closer distance between porphyrin and fullerene entities.