Synthesis and Structural Characterization of Alkylgallium−Phosphorus Compounds. X-ray Crystal Structures of (Me3CCH2)2(Cl)Ga·P(SiMe3)3, R2GaP(SiMe3)2GaR2Cl (R = Me3CCH2, Me3SiCH2), and [(R)(X)GaP(SiMe3)2]2 (R = Me3CCH2, X = Cl; R = Me3CCH2, X = Me3CCH2; R = Me3SiCH2, X = Br)

Abstract

Reaction of (Me3CCH2)2GaCl with (Me3Si)3P in a 1:1 mole ratio does not result in any intermolecular dehalosilylation but affords the adduct (Me3CCH2)2(Cl)Ga·P(SiMe3)3 (1) in nearly quantitative yield. Mixing (Me3CCH2)2GaCl and (Me3Si)3P in a 2:1 mole ratio yields as the only isolable product the dimeric compound [(Me3CCH2)(Cl)GaP(SiMe3)2]2 (2), which contains three different substituents on the gallium center. This type of product is also observed in the 2:1 reaction of (Me3SiCH2)2GaBr and (Me3Si)3P, where [(Me3SiCH2)(Br)GaP(SiMe3)2]2 (3) is obtained. The salt elimination reaction between (Me3CCH2)2GaCl and LiP(SiMe3)2 leads to the dimer [(Me3CCH2)2GaP(SiMe3)2]2 (4) in good yield. Equilibration of compound 4 with 2 molar equiv of (Me3CCH2)2GaCl produces the mixed-bridge species (Me3CCH2)2GaP(SiMe3)2Ga(CH2CMe3)2Cl (5) in nearly quantitative yield. The mixed-bridge compound (Me3SiCH2)2GaP(SiMe3)2Ga(CH2SiMe3)2Cl (6) results from the 2:1 dehalosilylation reaction of (Me3SiCH2)2GaCl and (Me3Si)3P. Various physical and spectroscopic data are presented for compounds 1−6, as well as the results of their X-ray crystal structure determinations.