Synthesis of dinuclear ruthenium (II) diphen complex of TAP and HAT

by Marutharaj, Tamelselvi; Durham, Bill; Millett, Francis Spencer

Elias et. al. have shown that mononuclear ruthenium complexes contg. the ligands 1,4,5,8-tetraazaphenanthrenes (TAP) and 1,4,5,8,9,10-hexaazatriphenylene (HAT) are strong photooxidants. Dinuclear complexes posses many features of the mononuclear complexes but have a larger overall charge and longer excited state lifetimes which can ultimately lead to higher overall yield of photoproducts. Our goal has been the synthesis of dinuclear ruthenium (II) complexes contg. TAP or HAT ligands with the metal centers coupled through 5,5'-bi(1,10-phenanthroline). Our synthetic approach to TAP ligand is by the condensation of glyoxal with 4-nitro-o-phenylenediammine followed by amination, redn. and further glyoxal condensation. We have synthesized the HAT ligand by condensing hexaketocyclohexane with 1,2-diaminoethylene followed by a series of HAT derivs. and decarboxylation of the resulting hexaazatriphenylenehexacarboxylic acid.