INTRAMOLECULAR ENERGY-TRANSFER IN RU(II)-RU(II) AND RU(II)-CR(III) POLYNUCLEAR COMPLEXES

Ligand-bridged polynuclear complexes made up of metal-containing subunits with long-lived excited states are suited for the study of intramolecular electronic energy transfer. Using Ru(II) and Cr(III) complex units as building blocks and cyanide as bridging ligand, a number of Ru(II)-Ru(II), Ru(II)-Cr(III) polynuclear complexes have been synthesized. Efficient intramolecular energy transfer between adjacent metal centers occurs in these systems, as shown by quenching and photosensitization of the appropriate emissions. When the behavior of the polynuclear complex is compared with that of the component subunits, a number of interesting effect, luminescence shift, enhanced population of the emitting state, photoprotection, excited-state intervalance transfer, chemiluminescent charge recombination. Possible developments of the results towards the design of photonic molecular devices are discussed. © 1990.