Ultrafast time-resolved laser spectroscopic studies of trans-bis(ferrocene- carboxylato)(tetraphenyl-porphyrinato)tin(IV): Intramolecular electron-transfer dynamics

Abstract

Photophysical properties of a newly-synthesized porphyrin derivative, trans-bis(ferrocene carboxylato)-(5,10,15,20-tetraphenylporphyrinato)tin(IV) [Sn(TPP)(FcCOO)2] were investigated by means of steady-state and fs-time resolved laser spectroscopic techniques, and compared with those of a standard molecule, trans-dichloro(5,10,15,20-tetraphenyl-porphrinato)tin(IV) [Sn(TPP)Cl2]. The fluorescence spectrum of Sn(TPP)-(FcCOO) 2 was observed to exhibit dual emission bands originating from the S2-state and the S1-state, which was greatly quenched as compared to those of Sn(TPP)Cl2. The fs-time resolved fluorescence and transient absorption spectroscopic measurements revealed that the fluorescence quenching is due to formation of the long-lived charge transfer state by intramolecular electron transfer from ferrocene to the S 2-excited SnTPP in addition to the enhanced non-radiative deactivation processes.