Electronic Structural Model for the Emitting MLCT Excited States of Ru(Bpy) sub 32+ and Os(Bpy) sub 32+

摘要

More experimental evidence is needed in order to completely resolve the question of localization versus delocalization for the metal ligand charge transfer (MLCT) excited states of Ru(bpy) sub 32+ and Os(bpy) sub 32+ . The important point of the present work is that only four low-lying states are predicted and their polarization properties are well-defined. Since there is a one-to-one correspondence of predicted to observed states, availability of the polarization data should lead directly to an assignment of the states or to a rejection of the model. Unfortunately, a similar situation does not exist for the delocalized alternative. In a semi-qualitative analysis of the absorption spectra of the two complexes using a delocalized model as demanded by exciton theory, we predicted the existence of five low-lying MLCT excited states. Since the delocalized model gives more predicted than observed states, the goal of obtaining a definitive assignment or of providing a basis for rejection of the model would be more difficult based on the experiment. However, a distinction between the two models could probably be made readily solely on the basis of polarization data over the temperature range 1.7 to 300 K. 6 tables. (ERA citation 08:041761)