Preparation and chemistry of Me 3SiCH 2AsH 2; Preparation of [Me 3SiCH 2(H)AsGaPh 2] 3, a trimeric mono(arsino)gallane containing a hydrogen bonded to arsenic. Isolation and X-ray crystal structure of (Me 3SiCH 2As) 5

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Reduction of Me 3SiCH 2AsCl 2 ( I) with LiA1H 4 at −78°C afforded Me 3SiCH 2 AsH 2 ( II) and reaction of II with Ph 3Ga produced [Me 3SiCH 2(H)AsGaPh 2] 3 ( III) which was characterized by partial elemental analysis (C and H), 1H NMR spectroscopy and a cryoscopic molecular weight determination. Based on 1H NMR data, [Me 3SiCH 2 (H)AsGaMe 2] 3 ( IV) was produced by the reaction of II with Me 3Ga; however, only H 2, Me 4Si, (Me 3SiCH 2As) 5 ( VI) and unreacted (Me 3SiCH 2) 3Ga were identified after allowing the latter to react with II. Reaction of 2 equiv. of Me 3SiCl with a mixture of II and n-BuLi (1 : 2 mole ratio) afforded Me 3SiCH 2As(SiMe 3) 2 ( V). The monosilylated arsine was not isolated when 1 equiv. of Me 3SiCl was allowed to react with combined II and n-BuLi (1 : 1 mole ratio); rather, a mixture of II and V resulted. Attempted preparations of (Me 3SiCH 2AsGaPh) n , are described. The ring compound, VI, was prepared by reaction of I with a mixture of Me 3SiCl and Mg in THF. The molecular structure of this cycloarsane was determined by single-crystal X-ray diffraction methods. Pale yellow crystals of VI belong to the monoclinic system with four molecules occupying the general positions of space group P2 1/ c( C 2 h 5)with cell constants: a = 9.952(1), b = 30.245(9), c = 13.000(3) Å, β = 91.69(1)°, V = 3911.3 Å 3, Z = 4.