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-a lkyl and metal-halide bonds by visible excitation of alpha-diimine com plexes into their MLCT transitions. It is shown that mechanistic infor mation about these reactions can best be obtained from the alkyl compl exes which show a strong dependence of their quantum yield on the alky l group. A detailed mechanism is presented for the photochemistry of f ac-XMn(CO)3 (alpha-diimine)(X = halide) which complexes, quite unexpec tedly, photodecompose into radicals Mn+(CO)3(alpha-diimine.-) via thei r mer-isomers.