Cluster-to-ligand charge transfer

The triruthenium derivatives 31-35 show characteristic intracluster charge transfer (IC) absorptions in the visible to near-infrared region (600-1000 nm) and cluster-to-ligand charge transfer (CLCT) transitions at 320-450 nm. Compared with the low energy bands in [Ru3n m m]+ complexes 31-35, those in the one-electron reduced neutral [Ru3 ]° species are remarkably red-shifted. The decrease in energy for these transitions by one-electron reduction reflects a rise of the occupied d% levels as the number of electrons increases. Complexes 31-35 exhibit... 

Spence T G, Trotter B T, Burns T D and Posey L A 1998 Metal-to-ligand charge transfer in the gas phase cluster limit J. Phys. Chem. A 102 6101... 

In fluid solutions, the resolvation times can be in the subnanosecond time regime. For example, the rapid (<100 ps) relaxation of the excited-state absorption spectra of ruthenium polypyridyl complexes following metal-to-ligand charge-transfer (MLCT) excitation in aqueous solutions have been ascribed to diffusional resolvation of the MLCT excited state. Finally, Robinson and co-workers have provided evidence that the rate of ionization of the singlet excited state of 6-p-toluidine-2-naphthalenesulfonate is determined by the rate at which neighboring solvent fluctuations can form a 3-4 water molecule cluster capable of solvating the electron. 

These three types of clusters all involve one electron orbital. They provide a basis for the description of the d-d (i. e. ligand field) transitions and the ligand to metal charge transfer transitions which are responsible for most of the UV-visible spectra and opti-... 

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