The photophysical and photochemical properties of Ru(bpy)32+ cation exchanged onto porous Vycor glass have been determined as a function of temperature. In the 5-95 °C range, the spectroscopic properties of the adsorbed complex are equivalent to aqueous solution spectra at the same temperature. The emission lifetime of the adsorbed complex declines with increasing temperature, but the emission polarization ratio is independent of temperature and equivalent to that measured in hydrocarbon glasses at 77 K. Photolysis of the adsorbed complex leads to disproportionation, and the quantum yield of the reaction increases with increasing temperature. The latter is interpreted within a surface conduction model where an Arrhenius plot of the quantum yield data indicates that the barrier to electron transport on the glass surface is 6.87 • 0.11 kcal/mol.

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Excitation (410 nm) of the bimetallic [(bpy)(2)Ru(CN)(mu-CN)Rh(NH(3))(4)Br](2+) produces the MLCT state localized on the (bpy)(2)Ru(CN)(2) ligand. Photoinduced cleavage of the bimetallic occurs in the presence of [H(+)], and the dependence yields a K(a) equivalent to that for ground-state cis-(bpy)(2)Ru(CN)(2) implying separation of the bimetallic prior to relaxation. The pH dependence and the emissivity of a bimetallic composed of components that individually quench at a diffusion controlled rate suggest that rupture of the RuCN-Rh bond is due to the reduction in electron density at the cyano ligand that occurs on population of the MLCT state. Unlike known photoinduced metal ligand dissociations, where the excitation energy is consumed in the dissociation, the dissociated "(bpy)(2)Ru(CN)(2) ligand" remains excited.