Cyclometallated and cyclometalsilylated complexes of transition elements as photoredox sensitizers

An account of a vastly improved synthesis of tris-ortho-metalated Ir(III) complexes of 2-phenylpyridine and related ligands has been published. The emission energies, excited state lifetimes and ground state oxidation potentials of these species have also been reported, and from these data potentials for the excited states to function as reducing agents can be estimated. These estimates as well as a summary of several potential means for using these and related photocatalysts to carry out demanding chemical reductions and oxidations have also been published. Several projects within this area are being actively researched at this time, including the following: (a) production of strong reducing agents by photoreduction of tris-ortho-metalated species; (b) precursors for generation of solvated monomeric photocatalysts, and; (c) photochemical methanol production from CO{sub 2} and H{sub 2}O