Transition Metal Complexes as Mediators in Photochemical and Chemiluminescence Reactions

Transition metal complexes can play the role of photosensitizes in light driven electron transfer reactions and the role of chemiluminescence inducers in exoergonic electron transfer reactions. A unifying view of these processes is given and their relevance concerning the interconversion of light, chemical energy and electrical energy is emphasized. Ru(bpy) is presently the most used photosensitizer and chemiluminescence inducer. Several specific processes mediated by Ru (bpy)2+ 3 (including water splitting by solar energy, generation of light from the reaction between lead dioxide and oxalic acid and “firefly” type emission from the oscillating Belousov-Zhabotinskii reaction) are described.