Metal catalyzed activation of E-hydrogen bonds, E = silicon, germanium, tin
A new catalytic system involving iron and molybdenum complexes of the type: (η5-C5H5)M(CO) nMe, and (η5-C5H5)M(CO) n-1(PPh3)Me, M = Fe, n = 2 (1); M = Mo, n = 3 (2), were used to catalyze the dehydrogenative dimerization of di-t-butyltin dihydride to 1,2-dihydro-1,1,2,2-tetra- t-butyl-distannane, tBu2HSn-SnH tBu2 both photochemically and thermally. The thermal catalytic process is much more efficient than the photochemical process and the Mo catalysts are relatively more active than the corresponding Fe catalysts. A mechanism involving oxidative addition and reductive elimination steps has been suggested involving the intermediacy of (η5-C5H5 )M(CO)nSntBu2H. This complex was observed during the reaction and was independently synthesized and completely characterized by single crystal X-ray structural analysis and 13C, 119Sn and 1H NMR spectroscopy. It was also shown to be catalytically active for dehydrogenative dimerization, Scheme 1.1.*
*Please refer to dissertation for diagrams.