Intercomponent perturbation of MLCT spectra

All the complexes of this series contain the -Ru(bpy)2- chromophore, which has a typical absorption spectrum, dominated by intense metal-to-ligand charge transfer (MLCT) transitions in the visible. When further metal centers are attached to this chromophore by means of bridging cyanides, the MLCT transitions are still present, but their energy is somewhat perturbed. Some relevant examples [65,67-70,73,74] are collected in Table I, where Ru(III)/Ru(II) redox potentials are also given in addition to MLCT absorption maxima. It is seen that the extent of intercomponent perturbation depends on several factors (i) presence of the additional metal center (see. 

These experimental results clearly indicate that, although the -Ru(bpy)2 - molecular component maintains its characteristic properties (e.g., MLCT absorption in the 400-500 nm range, oxidation potential in the (-i-0.8)-(+l.l) V vs SCE range) in the cyano-bridged polynuclear 

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