MECHANISMS OF THE PHOTOSUBSTITUTION OF RUTHENIUM(II) POLYPYRIDINE COMPLEXES - FORMATION OF AN INTERMEDIATE WITH A MONODENTATE POLYPYRIDINE LIGAND AND ITS REACTIONS

A novel intermediate of the photosubstitution of [Ru(bpy)2(dmbpy)]2+ ( dmbpy=3,3'-dimethyl-2,2'-bipyridine) with a monodentate dmbpy was iden tified and its structure in solution was determined. Quantum yields of the formation of the intermediate and of the net photosubstitution of the complex were measured in various solvents. Rate of the thermal re chelation of the monodentate dmbpy in the intermediate was also measur ed. The data indicated that the formation of the intermediate proceede d by dissociative mechanism. Refered to the dmbpy complex the reaction s of [Ru(bpy)3]2+ and [Ru(phen)3]2+ were concluded,to proceed by disso ciative interchange mechanism, and [Ru(bpy)2(L)2]2+ (L=pyridine, imida zole, NH3, ethylenediamine/2, and picolylamine/2) by dissociative mech anism.