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

Abstract

The known cyclic dimer, (Me 3SiNSiMe 2) 2 ( 1), was isolated in the reaction of GaCl 3 with one equivalent of Li[N(SiMe 3) 2] at room temperature as the result of cleavage of a SiC bond from the N(SiMe 3) 2 anion. Although the gallium product was not isolated from the GaCl 3 reaction, pyrolysis of the new base-stabilized dichloro(silyl)amido gallium compounds, Cl 2Ga[N(SiMe 3) 2](quin) ( 2) (quin=quinuclidine), Cl 2Ga[N(SiMe 3) 2](NMe 3) ( 3), Cl 2Ga[N(SiMe 3)( t Bu)](quin) ( 4) and Cl 2Ga[N(SiMe 3)(2,6- i PrC 6H 3)](quin) ( 5), afforded MeGaCl 2(quin) and MeGaCl 2(NMe 3) 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 GaNSiM 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.