Inorganic Chemistry, Vol.37, No.17, 4460-4465, 1998
Crown ether encapsulation effects on the optical properties of delocalized and partially localized bridged ruthenium dimers
The effects of crown ether encapsulation on the position of the near-IR-vis bands of [(NH3)(5)Ru-pyz-Ru(NH3)(5)](m+) and [(NH3)(5)Ru-(4,4'-bpy)-Ru(NH3)(5)](m+) (m = 4, 5) have been investigated within a purely electronic picture. The model accounts for the observed behavior and furnishes a theoretical explanation. The near-IR band, observed experimentally around 1 eV, is found to be a metal-to-ligand charge-transfer transition, in contrast to the common idea that ascribes it to an intervalence transition (Ferretti, A.; Lami, A.; Villani, G. Inorg. Chem. 1998, 37, 2799). The results obtained are a further confirmation that the model proposed contains all the essential ingredients for a basic minimal description of electron transfer in donor-bridge-acceptor systems.