Ultrafast Time-Resolved Laser Spectroscopic Studies of trans-Bis(ferrocene-carboxylato)(tetraphenyl-porphyrinato)tin(IV) : Intramolecular Electron-Transfer Dynamics

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)Cl 2 ]. The fluorescence spectrum of Sn(TPP)-(FcCOO) 2 was observed to exhibit dual emission bands originating from the S 2 -state and the S 1 -state, which was greatly quenched as compared to those of Sn(TPP)Cl 2 . 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.