THE KINETICS AND MECHANISM OF THE PYROLYSIS OF MANGANESE AND MANGANESE SILICIDE CVD PRECURSORS

The gas-phase pyrolysis of methyl pentacarbonyl manganese and acetyl p entacarbonyl manganese, both alone and in the presence of trimethyl si lane, has been investigated using stirred flow reactor kinetic measure ments and IR laser powered pyrolysis, together with electron spin reso nance (ESR) detection of radical intermediates. For methyl pentacarbon yl manganese alone, all observations support a mechanism initiated by methyl-manganese bond homolysis, whereas the initial step in the acety l compound involves CO loss and methyl migration. The addition of trim ethylsilane sensitizes decomposition of MeMn(CO)(5), yielding methane and trimethylsilyl pentacarbonyl manganese; on the other hand, Me3SiH has little effect on the rate of decomposition of MeCOMn(CO)(5). A mec hanism based on methyl migration is proposed to account for these obse rvations.