EXCITED-STATE ELECTRON-TRANSFER REACTIONS OF TRIS(4,4'-DIALKYL-2,2'-BIPYRIDINE)RUTHENIUM(II) COMPLEXES WITH PHENOLATE IONS - STRUCTURAL AND SOLVENT EFFECTS

The reductive quenching of three *RuL3(2+) complexes (L=4,4'-dialkyl-2,2'-bipyridine) by several substituted phenolate ions was investigated by the luminescence quenching technique. The decrease in the quenching constant k(q) with an increase in the size of the ligand is explained in terms of a change in DELTAG and the electron transfer distance. The p values obtained for the reactions of the three RuL3(2+) complexes with phenolate ions are in accordance with the reactivity-selectivity principle. The influence of the solvent on the photoredox reaction of Ru(bpy)3(2+) (bpy, 2,2'-bipyridine) reveals that, in addition to the bulk properties, the change in solvent reorganization energy (lambda(o)) and solvent longitudinal relaxation time (tau(L)) influence the values of the quenching rate constants.