- Molecular Zinc Species with Ge-Zn and Sn-Zn Bonds: A Reversible Insertion of a Stannylene into a Zinc-Carbon Bond
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The tetrylenes Ge(ArMe6)2 and Sn(ArMe6)2 (ArMe6 = C6H3-2,6-(C6H2-2,4,6-(CH3)3)2) reacted with dimethylzinc to afford the insertion products (ArMe6)2Ge(Me)ZnMe (1) and (ArMe6)2Sn(Me)ZnMe (3), which feature Ge-Zn and Sn-Zn bonds as well as two-coordinate zinc atoms. Crystals of 1 were found to be unsuitable for X-ray crystallography, so the ethyl-substituted (ArMe6)2Ge(Et)ZnEt (2) was synthesized in a parallel way to provide crystals suitable for X-ray studies. These showed the structure to be similar to that of 3. The reaction of Pb(ArMe6)2 with dimethylzinc yielded ArMe6ZnMe with a linearly coordinated zinc atom via ligand exchange but no characterizable, new lead product was obtained. The reaction of Sn(ArMe6)2 with dimethylzinc is reversible in hydrocarbon solution at room temperature and displayed a dissociation constant Kdiss and a ΔGdiss of 0.0028(5) and 14(4) kJ mol-1 at 298 K, respectively. Compounds 1-4 were characterized by NMR and IR spectroscopy as well as by X-ray crystallography for 1, 3, and 4.
- Erickson, Jeremy D.,Riparetti, Ryan D.,Fettinger, James C.,Power, Philip P.
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- Reaction of a germylene, stannylene, or plumbylene with trimethylaluminum and trimethylgallium: Insertion into Al-C or Ga-C bonds, a reversible metal-carbon insertion equilibrium, and a new route to diplumbenes
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The reaction of the tetrylenes Ge(ArMe6)2, Sn(ArMe6)2, and Pb(ArMe6)2 [ArMe6 = C6H3-2,6-(C6H2-2,4,6-(CH3)3)2] with the group 13 metal alkyls trimethylaluminum and trimethylgallium afforded (ArMe6)2Ge(Me)AlMe2 (1), (ArMe6)2Ge(Me)GaMe2 (2), and (ArMe6)2Sn(Me)GaMe2 (3) in good yields via insertion reaction routes. In contrast, the reaction of AlMe3 with Sn(ArMe6)2 afforded the [1.1.1]propellane analogue Sn2{Sn(Me)ArMe6}3 (5) in low yield, and the reaction of AlMe3 or GaMe3 with Pb(ArMe6)2 resulted in the formation of the diplumbene {Pb(Me)ArMe6}2 (6) and AlArMe6Me2 (7) or GaArMe6Me2 (8) via metathesis. The reaction of Sn(ArMe6)2 with gallium trialkyls was found to be reversible under ambient conditions and analyzed through the reaction of Sn(ArMe6)2 with GaEt3 to form (ArMe6)2Sn(Et)GaEt2 (4), which displayed a dissociation constant Kdiss and ΔGdiss of 8.09(6) × 10-3 and 11.8(9) kJ mol-1 at 296 °C. The new compounds were characterized by X-ray crystallography, NMR (1H, 13C, 119Sn, and 207Pb), IR, and UV-vis spectroscopies.
- Erickson, Jeremy D.,Fettinger, James C.,Power, Philip P.
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p. 1940 - 1948
(2015/06/16)
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- Synthesis and characterization of the monomeric diaryls M{C6H3-2,6-Mes2}2 (M = Ge, Sn, or Pb; Mes = 2,4,6-Me3C6H2-) and dimeric aryl-metal chlorides [M(Cl){C6H3-2,6-Mes2}]2 (M = Ge or Sn)
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The reaction of 2 equiv of LiC6H3-2,6-Mes2 (Mes = 2,4,6-Me3C6H2-) with GeCl2·dioxane, SnCl2, or PbCl2 in ether solution has resulted in the isolation of rare examples of monomeric, σ-bonded, diaryl derivatives M{C6H3-2,6-Mes2}2 (M = Ge (1), Sn (2), or Pb (3)). The compounds 1-3 are thermally stable, purple, crystalline solids with V-shaped geometries and remarkably wide (ca. 114.5°) interligand bond angles. The monoaryl metal chloride derivatives [M(Cl){C6H3-2,6-Mes2}]2 (M = Ge (4) or Sn (5)) were isolated by treatment of the appropriate dichlorides with either 1 equiv of LiC6H3-2,6-Mes2 or 1 equiv of the diaryls 1 or 2. The orange germanium compound 4 has a dimeric structure in which the monomers are linked by a relatively weak, 2.443(2) A?, Ge-Ge interaction. In sharp contrast, its yellow tin analogue 5 has a dimeric structure in which three-coordinate tin centers are associated by asymmetrically bridging chlorides. The compounds 1-3 constitute a unique, structurally characterized diaryl series for Ge, Sn, and Pb and display evidence of steric crowding that is significantly greater than that observed in previously known σ-bonded diorgano group 14 derivatives. The compounds 4 and 5 are the first fully structurally characterized organometal halide derivatives of Ge or Sn in which the organic ligand is monodentate, purely σ-bonded, and nonchelating.
- Simons, Richard S.,Pu, Lihung,Olmstead, Marilyn M.,Power, Philip P.
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p. 1920 - 1925
(2008/10/08)
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