Supramolecular Complexation of Porphyrin and Quinone with Two Coordination Bonds and Intramolecular Electron Transfer

Abstract

V-shaped zinc porphyrin dimer and quinone with two pyridyl groups have been rationally designed and synthesized to assemble a porphyrin-quinone supramolecule with two coordination bonds. Selective formation of the 1:1 bridging structure between the host-guest molecules was seen by 1 H NMR and UV-Vis absorption spectroscopy. Molecular mechanics calculation suggests that the bridging structure has rigidity as well as flexibility in geometry between the redox pair, which supports the interpretation of 1 H NMR studies. Intramolecular photoinduced electron transfer from the excited singlet state of the porphyrin to the quinone was observed by steady-state fluorescence spectra and picosecond fluorescence lifetime measurements.