Synthesis and Characterization of Sterically Hindered Alkylaluminum−Phosphorus and −Arsenic Compounds. X-ray Crystal Structures of (Me3ECH2)3Al·E‘(SiMe3)3(E = Si, E‘ = As; E = C, E‘ = P, As), (Me3SiCH2)2(Br)Al·P(SiMe3)3, and [(Me3SiCH2)(X)AlE(SiMe3)2]2(X = Br, E = P, As; X = Me3SiCH2, E = As)

Abstract

Abstract : Reaction of (Me3SiCH2)3Al with E(SiMe3)3 (E = P, As) in a 1:1 mole ratio affords the Lewis acid-base adducts (Me3SiCH2)3Al.P(SiMe3)3 (1) and (Me3SiCH2)3Al.As(SiMe3)3 (2). Similarly, the 1:1 mole ratio reaction of (Me3CCH2)3Al with E(SiMe3)3 (E = P, As) leads to the isolation of (Me3CCH2)3Al.P(SiMe3)3 (3) and (Me3CCH2)3Al.As(SiMe3)3 (4). The adduct (Me3SiCH2)2(Br)Al.P(SiMe3)3 (5) was obtained from the 1:1 mole ratio reaction of (Me3SiCH2)2AlBr with P(SiMe3)3. The dimers (Me3SiCH2)(Br)AlP(SiMe3)22 (6) and (Me3SiCH2)(Br)AlAs(SiMe3)22 (7) were isolated as products of the lithium halide elimination reactions of (Me3SiCH2)AlBr2 (10) with LiE(SiMe3)2 (E = P, As), while reaction of (Me3SiCH2)2AlBr with these same lithium pnictide salts leads to the isolation of (Me3SiCH2)2AlP(SiMe3)22 (8) and (Me3SiCH2)2AlAs(SiMe3)22 (9). Various physical and spectroscopic data, including a variable temperature NMR study of the dimeric compounds 6 through 9, are presented for the above compounds, as are the single crystal X-ray structures of 2 through 7 and 9.