Excited State Dynamics of Isocyano Rhenium(I) Phenanthroline Complexes from Time-Resolved Spectroscopy.

The photophysical processes in a series of isocyano Re(I) phenanthroline complexes {[Re(CNR)n (CO)4-n (phen)](PF6 ); n=2, 3, 4, R=2,6-(i Pr)2 C6 H3 - or t Bu- (n=2)} in acetonitrile have been studied by resonance Raman spectroscopy, transient resonance Raman spectroscopy, and femtosecond / nanosecond transient spectroscopy to elucidate the nature of their electronic transitions and emissive excited state(s). The kinetics of the intersystem crossing, vibrational relaxation and radiative decay of the metal-to-ligand charge transfer {MLCT [dπ(Re)→π*(phen)]} excited state have also been determined.