ARRHENIUS PARAMETERS FOR H+(CH3)(3)GEH AND (CH3)(2)GEH2

Rate constants for the reactions of H atoms with the methylgermanes, ( CH3)(3)GeH and (CH3)(2)GeH2, have been measured by flash photolysis in the temperature range 298-510 K. H atoms were generated by the mercur y-sensitized photolysis of H-2 and monitored by Lyman-alpha absorption . The values obtained are given by, respectively, k(1)/cm(3) s(-1) = ( 8.80 +/- 1.09:) x 10(-11) exp[(-929 +/- 45)/T] k(2)/cm(3) s(-1) = (9.6 4 +/- 1.51) x 10(-11) exp[(- 854 +/- 56)/T] The results indicate that the reactivity of the Ge-H bond towards H atom attack is increased by methyl substitution, the relative magnitude of the effect being the sa me as that observed for attack on the Si-H bond in the methylsilanes.