PHOTOPHYSICAL PROPERTIES OF RE(CO)(3)L-3(- ELECTRONIC DELOCALIZATION EFFECT IN METAL-TO-LIGAND CHARGE-TRANSFER EXCITED-STATES() (L = MONOAZINE) COMPLEXES )

The photophysical properties of the series of the [Re(CO)(3)L-3]CF3SO3 (L = 4-phenylpyridine, 3-phenylpyridine, 4-benzylpyridine, 4-(4'-nitr obenzyl)-pyridine and 4,4'-bipyridine) have been studied. Emission spe ctral changes with temperature and biexponential decay of the luminesc ence both in dichloromethane fluid solution and frozen (77 K) media sh ow two excited states, intraligand (IL) and metal-to-ligand charge tra nsfer (MLCT) in character, emitting with intrinsic rates. Rates of MLC T emission badly correlate with the excited state-ground state energy gap. Departures from the energy gap law are rationalized in terms of e xcited state distortion and electronic delocalization. (C) 1998 Elsevi er Science S.A. All rights reserved.