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A series of group 13 metal complexes featuring the beta-diketiminate ligand [[(C(6)H(3)-2,6-i-Pr(2))NC(Me)](2)CH](-) (i.e., [Dipp(2)nacnac](-), Dipp = C(6)H(3)-2,6-i-Pr(2)) have been prepared and spectroscopically and structurally characterized. The chloride derivatives Dipp(2)nacnacMCl(2) (M = Al (3), Ga (5), In (8)) were isolated in good yield by the reaction of 1 equiv of Dipp(2)nacnacLi.Et(2)O (2) and the respective metal halides. The iodide derivatives Dipp(2)nacnacMI(2) (M = Al (4), Ga (6), In (9)), which are useful for reduction to afford M(I) species, were made by a variety of routes. Thus, 4 was obtained by treatment of the previously reported Dipp(2)nacnacAlMe(2) with I(2), whereas the gallium analogue 6 was obtained as a product of the reaction of "GaI" with Dipp(2)nacnacLi.Et(2)O, and 9 was obtained by direct reaction of InI(3) and the lithium salt. The methyl derivatives Dipp(2)nacnacMMe(2) (M = Ga (7), In (10)), which are analogous to the previously reported Dipp(2)nacnacAlMe(2), were synthesized by the reaction of GaMe(3) with Dipp(2)nacnacH (1) or by reaction of the indium chloride derivative 8 with 2 equiv of MeMgBr in diethyl ether. The compounds 3-10 exist as colorless, air- and moisture-sensitive crystalline solids. Their X-ray crystal structures feature nearly planar C(3)N(2) arrays in the Dipp(2)nacnac ligand backbone with short C-C and C-N distances that are consistent with a delocalized structure. However, there are large dihedral angles between the C(3)N(2) plane and the N(2)M metal coordination plane which have been attributed mainly to steric effects. The relatively short M-N distances are consistent with the coordination numbers of the metals and the normal/dative character of the nitrogen ligands. The compounds were also characterized by (1)H and (13)C NMR spectroscopy. (1)H NMR data for 7 revealed equivalent methyl groups whereas the spectrum of 10 displayed two In-Me signals which indicated that ring wagging was slow on the (1)H NMR time scale.

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Three stable 1-silapropadienes 1a−c were prepared by the intermolecular addition of organolithium reagents at the carbon−carbon triple bond of fluoroalkynylsilanes 3a,b followed by LiF elimination. The structure of 1a and of the intermediate α-lithiated fluorosilane 2a were determined by X-ray diffraction. The chemical behavior of 1-silapropadienes 1a−c differs greatly depending on the substituents on the silicon atom. When two triisopropylphenyl groups were present (1a), typical addition reactions of the SiC double bond were observed. Thermolysis of 1a yielded benzosilacyclobutene 7. For the more hindered 1-silapropadienes 1b and 1c, no reaction was observed with dioxygen, benzaldehyde, 2,3-dimethylbutadiene, or trimethylchlorosilane at room temperature. However, thermolysis of 1b or treatment with excess ethanol under neutral or acidic conditions produced 8b, the product of an intramolecular insertion of the SiC double bond into an adjoining primary C−H bond of one tert-butyl group in an ortho-position of the supermesityl substituent. In the presence of EtOD and catalytic D2SO4, this reaction occurred very rapidly at −78 °C with over 95% incorporation of deuterium in the product.