pH-dependent luminescence of ruthenium(II) polypyridine complexes

The changes in the absorption and emission of three new complexes, [Ru(bpy)(2)L](2+)(1-3), upon a pH variation are considered and the mechanism of the changes is discussed. The luminescence quantum yields of complexes 2 and 3 are strongly influenced by the pH due to intramolecular photoinduced electron transfer, which depends on the pH of the environment.