Two modes of photoinduced twisted intramolecular charge transfer in meso-arylaminated subporphyrins

Abstract

Photoinduced twisted intramolecular charge transfer (TICT) of meso-(4-dimethylamino)phenylamino subporphyrin 2 and meso-(4-nitro)phenylamino subporphyrin 3 has been revealed by steady-state and time-resolved absorption/fluorescence experiments and quantum calculations. Subporphyrins 2 and 3 undergo molecular twisting at the C_meso–N bond and the N–C_ipso bond, respectively, to trigger intramolecular charge separation, which is restricted at low temperature or in viscous paraffin oil with concurrent fluorescence recovery of local excited states.