SiC bond cleavage in the reaction of gallium chloride with lithium bis(trimethylsilyl)amide and thermolysis of base adducts of dichloro(trimethylsilyl)amido gallium compounds

The known cyclic dimer, (Me3SiNSiMe2)2 (1), was isolated in the reaction of GaCl3 with one equivalent of Li[N(SiMe3)2] at room temperature as the result of cleavage of a SiC bond from the N(SiMe3)2 anion. Although the gallium product was not isolated from the GaCl3 reaction, pyrolysis of the new base-stabilized dichloro(silyl)amido gallium compounds, Cl2Ga[N(SiMe3)2](quin) (2) (quin=quinuclidine), Cl2Ga[N(SiMe3)2](NMe3) (3), Cl2Ga[N(SiMe3)(tBu)](quin) (4) and Cl2Ga[N(SiMe3)(2,6-iPrC6H3)](quin) (5), afforded MeGaCl2(quin) and MeGaCl2(NMe3) in 27–61% yields confirming a methyl migration from Si to Ga. The SiC bond cleavage and methyl migration were proposed to occur through transition states containing a e ring. No unusual Ga⋯C interaction was found in the solid-state structure of 2 that was monomeric with the gallium atom adopting a distorted tetrahedral geometry. Improved structural data for 1 are also reported.