Attachment of the New Bulky Ligand (Me3Si)2(Me2NMe2Si)C to Li, Hg, Al, Ga, and Sn. Crystal Structures of [Li{C(SiMe3)2(SiMe2NMe2)}(THF)2], [Hg{C(SiMe3)2(SiMe2NMe2)}2], [Al{C(SiMe3)2(SiMe2NMe2)}X2] (X = Cl, Ph), and [Ga{C(SiMe3)2(SiMe2NMe2)}Cl2]

The organolithium reagent (1) is readily obtained by reaction of the chloride (Me3Si)2(Me2NMe2Si)CCl with LiBu in THF (tetrahydrofuran) at low temperature. Reactions of 1 with HgBr2, AlCl3, GaCl3, and SnCl4 give [Hg{C(SiMe3)2(SiMe2NMe2)}2] (2), (3), Ga{C(SiMe3)2(SiMe2NMe2)}Cl2 (5), and [Sn{C(SiMe3)2(SiMe2NMe2)}Cl3] (6), respectively, and treatment of 3 with LiPh gives (4). Crystal structure determinations have shown that there is intramolecular coordination of the N atom to the metal M, with formation of a planar four-membered ring, in 1, 3, 4, and 5 (but not 2). Engagement of the lone pair on N in coordination with Al in 3 results in an exceptionally long Si−N bond length of 1.875(2) Å, some 0.16 Å longer than that in 2 and in simple silylamines generally; the Si−N bond is possibly shorter in 4 (1.851(2) Å) and 5 (1.858(4) Å), and is markedly so in 1 (1.796(4) Å), but still notably long. The lengths of the N−metal bonds in these compounds are similar to those between alkylamines and the metals in coordination compounds, indicating that at least in these systems the N atoms in the silylamines coordinate as strongly as those in the organic amines. Reaction of 6 with MeOH occurs exclusively at the Si−N bond to give [Sn{C(SiMe3)2(SiMe2OMe)}Cl3], that of 2 with ICl or CF3CO2H gives [Hg{C(SiMe3)2(SiMe2Cl)}2] and [Hg{C(SiMe3)2(SiMe2O2CCF3)}2], respectively, and that of 1 with ICH2CH2I gives the iodide (Me3Si)2(Me2NMe2Si)CI.