INTER-CHROMOPHORE ELECTRONIC INTERACTIONS IN LIGAND-BRIDGED POLYNUCLEAR COMPLEXES - A COMPARATIVE-STUDY OF VARIOUS BRIDGING LIGANDS

A brief survey of various bridging ligands that are currently availabl e for the synthesis of light harvesting systems and of the principles of analysis of electronic coupling is followed by a comparative analys is on what is known on the role of bridging ligands in modulating the electronic communication between the chromophores. Polynuclear complex es of the type [(LL)(2)M(1)-(BL(1))-M(2)(LL')(2)](n+) and BL(2))-M(2)( LL')(2)-(BL(2))-M(3)(LL'')(2)(X)](n+), where LL, LL', LL'' refer to bi pyridine-type ligands (or non-chromophoric ones such as -Cl, H2O, -CN, CO, ...); BL(1) represent bis-bidentate type bridging ligands such as dpp or BPBT and BL, represent bis-monodentate such as cyanide; M(1), M(2) and M(3) stand for the metal centres Ru(II), Os(II) and Re(I), ar e considered.