The Attempted Syntheses of Low Oxidation State, Organometallic Derivatives of Aluminum, Gallium and Indium, a New Synthesis of Al(CH2SiMe3)3

摘要

The synthesis of KAl(CH2SiMe3)2 by a reductive elimination reaction between Al(CH2SiMe3)3 and KH has been attempted but a pure product could not be isolated. The reactants combine at 70 C to form KAl(CH2SiMe3)3H, a white pyrophoric solid, which has been fully characterized. A molecular weight study indicates the presence of a mixture of monomeric and dimeric species in benzene solution. The pyrolysis of KAl(CH2SiMe3)3H at 205 C produces Si(CH3)4 but also CH4. The formation of Si(CH3)4 suggests that KAl(CH2SiMe3)2 might have been formed but the presence of CH4 indicates that a decomposition reaction occurs either prior to or after the formation of KAl(CH2SiMe3)2. The reactions of mixtures of KH-Al(CH3)3, KH-Ga(CH3)3, NaH-Ga(CH3)3, KH-In(CH3)3 and NaH-In(CH3)3 have also been investigated in order to determine the role of the organic substituent in the attempted reductive elimination reactions. In all cases the formation of CH4 during pyrolysis of KAl(CH3)H, KGa(CH3)3H and the other reaction mixtures is consistent with the occurrence of reduction but no pure compounds could be isolated. A new synthetic route to Al(CH2SiMe3)3 from AlBr3 and LiCH2SiMe3 in refluxing hexane is also described. (Author)