THE PHOTOCHEMICAL FORMATION OF ORGANOMETALLIC RADICALS FROM ALPHA-DIIMINE COMPLEXES HAVING A METAL-METAL, METAL-ALKYL OR METAL-HALIDE BOND

This article describes the homolytic splitting of metal-metal, metal-alkyl and metal-halide bonds by visible excitation of alpha-diimine complexes into their MLCT transitions. It is shown that mechanistic information about these reactions can best be obtained from the alkyl complexes which show a strong dependence of their quantum yield on the alkyl group. A detailed mechanism is presented for the photochemistry of fac-XMn(CO)3 (alpha-diimine)(X = halide) which complexes, quite unexpectedly, photodecompose into radicals Mn+(CO)3(alpha-diimine.-) via their mer-isomers.