Fluorescence quenching study of zinc bisporphyrins by fulleropyrrolidines and their N-oxides

Novel phenylene-bridged zinc bisporphyrins (1-4), fulleropyrrolidines (C-60-m, C-60-h) and their N-oxides (C-60-mo, C-60-ho) were synthesized. The fluorescence quenching processes of bisporphyrins in toluene solution by fulleropyrrolidines and their N-oxides were investigated by steady-state fluorescence spectra. The fluorescence quenching constants proved that the fluorescence quenching ability was decreased as reduction of the pyrrolidine functional groups of fullerene surface: C-60-h>C-60-m>C-60, and the fluorescence quenching ability was increased about 1.3-7.4 times by utilizing fulleropyrrolidine N-oxides (C-60-mo, C-60-ho) compared to fulleropyrrolidine compounds (C-60-m, C-60-h). The results revealed photoinduced electron transfer (PET) efficiency between bisporphyrin and fullerene derivatives could be tunable by change of functional groups on fullerene surface.