TUNING THE EXCITED STATES IN fac-[Re(X2dppz)(CO)3(L)]: INTRALIGAND, CHARGE TRANSFER OR BOTH?

Excited state lifetime measurements emission, emission lifetime and Resonance Raman have been conducted on the series fac-[Re(X2dppz)(CO)3(L)]0,+ (L = Cl-, 4-ethylpyridine (4-Etpy), 4,4´-bipyridine (4,4´-bpy)), with the X2dppz substituted dipyrido[3,2-a:2',3'-c] phenazine ligands (X = CH3 and Cl). The results are consistent with closely lying excited states, with pp * lowest, but MLCT contributing significantly to excited state lifetimes for the neutral complexes. fac-[Re(Cl2dppz)(CO)3Cl] appears to undergo a crossover from lowest pp* to lowest MLCT through the glass to fluid transition