The photophysics of fac-[Re(R)(CO)3(CO2Et-dppz)] + (R = py (1), 4-Me2N-py (2); CO2Et-dppz = dipyrido[3,2a:2′,3′c]phenazine-11-carboxylic ethyl ester) was studied with luminescence spectroscopy and time-resolved infrared (TRIR) spectroscopy in the metal carbonyl (2100-1800 cm-1) and organic ester (1800-1600 cm-1) regions. For 1, the picosecond TRIR spectra in the metal carbonyl region provided evidence for the formation of an intra-ligand IL (π-π*) excited state, which partially decays to an equilibrium with the metal-to-ligand charge transfer (MLCT) excited state. For 2 it is evident that both IL (π-π*) and MLCT excited states are formed within 2 ps of excitation. The magnitude of the ν(CO) shift in the metal carbonyl region following excitation allows the MLCT excited states to be described more precisely as a dπ(Re) → π*(phenazine) 3MLCT state for 1 and as a dπ(Re) → π*(phenanthroline) 3MLCT state for 2.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry