Elimination of bis(trimethylsilyl)stannylene from tris(trimethylsilyl)stannylated zirconocene and hafnocene chlorides

Reactions of (Me₃Si)₃SnK with Cp₂MCl₂ (M = Zr, Hf) give the respective stannylated metallocene chlorides. These complexes display a tendency to eliminate bis(trimethylsilyl)-stannylene under Cp₂M(Cl)SiMe₃ formation.     

Un Nouveau diphosphene stable: Le bis[tris(trimethylsilyl)methyl] diphosphene

A new stable diphosphene (Me₃Si)₃CPPC(SiMe₃)₃ has been isolated and characterized particularly by its NMR data; the ³¹P NMR chemical shift appears to be the largest ever observed.     

Synthesis of volatile bis[bis(trimethylsilyl)amide]-substituted boron derivatives

Russian Journal of General Chemistry - General strategy for the synthesis of organoboron compounds containing bis(trimethylsilyl)amide substituents has been suggested.     

Synthese,Eigenschaften und Struktur von Amin-Addukten der Lithium-tris[bis(trimethylsilyl)methyl]zinkate

Synthesis, Properties, and Structure of the Amine Adducts of Lithium Tris[bis(trimethylsilyl)methyl]zincates . Bis[bis(trimethylsilyl)methyl]zinc and the aliphatic amine 1,3,5-trimethyl-1,3,5-triazinane (tmta) yield in n-pentane the 1:1 adduct, the tmta molecule bonds as an unidentate ligand to the zinc atom. Bis[bis(trimethylsilyl)methyl]zinc · tmta crystallizes in the triclinic space group P1 with {a = 897.7(3); b = 1 114.4(4); c = 1 627.6(6) pm; α = 90.52(1); β = 103.26(1); γ = 102.09(1)°; Z = 2}. The central C₂ZnN moiety displays a nearly T-shaped configuration with a CZnC angle of 157° and Zn? C bond lengths of 199 pm. The Zn? N distances of 239 pm are remarkably long and resemble the loose coordination of this amine; a nearly complete dissociation of this complex is also observed in benzene. The addition of aliphatic amines such as tmta or tmeda to an equimolar etheral solution of lithium bis(trimethylsilyl)methanide and bis[bis(trimethylsilyl)methyl]zinc leads to the formation of the amine adducts of lithium tris[bis(trimethylsilyl)methyl]zincate. Lithium tris[bis(trimethylsilyl)methyl]zincate · tmeda · 2 Et₂O crystallizes in the orthorhombic space group Pbca with {a = 1 920.2(4); b = 2 243.7(5); c = 2 390.9(5) pm; Z = 8}. In the solid state solvent separated ions are observed; the lithium cation is distorted tetrahedrally surrounded by the two nitrogen atoms of the tmeda ligand and the oxygen atoms of both the diethylether molecules. The zinc atom is trigonal planar coordinated; the long Zn? C bonds with a value of 209 pm can be attributed to the steric and electrostatic repulsion of the three carbanionic bis(trimethylsilyl)methyl substituents.     

Reactions of bis(trimethylsilyl)amine and -amide with MoOCl4

Oxo-Mo(VI) imido-chloride, [MoOCl₂(NH)(Et ₂O)] _n and nitrido-chloride, [Mo₂O₂Cl₂(N)₂(Et ₂O)] _n have been synthesized by equimolar reactions of MoOCl₄ with HN(SiMe ₃)₂ and LiN(SiMe ₃)₂, respectively. Higher molar reactions of HN(SiMe ₃)₂ lead to imido-silylamido derivatives, [Mo₂OCl₃(NH)₃(NHSiMe ₃)] _n , whereas those of LiN(SiMe ₃)₂ give silylimido bridged compounds, Mo₄O₄Cl₄(NSiMe ₃)₆ and Mo₄O₄(NSiMe ₃)₈. Elemental analyses, redox titration, magnetic moment, molecular weight, molar conductance, infrared,¹H-NMR and TG-DTG-DTA studies are reported.

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Reaktionen von Bis(trimethylsilyl)amin und -amid mit MoOCl₄

Zusammenfassung Durch equimolare Reaktionen von MoOCl₄ mit HN(SiMe ₃)₂ und LiN(SiMe ₃)₂ wurden die Oxo-Mo(VI) Imido-chloride [MoOCl₂(NH)(Et ₂O)] _n und die Nitrido-chloride [Mo₂O₂Cl₂(N)₂(Et ₂O)] _n dargestellt. Höhermolekulare Reaktionen von HN(SiMe ₃)₂ führen zu Imido-silylamido Derivaten [Mo₂OCl₃(NH)₃(NHSiMe ₃)] _n , währenddessen die von LiN(SiMe ₃)₂ silylimidoüberbrückte Verbindungen ergeben: Mo₄O₄Cl₄(NSiMe ₃)₆ und Mo₄O₄(NSiMe ₃)₈. Die Strukturen sind mit Elementaranalysen, Redoxtitrationen, Messung der magnetischen Momente, Molekulargewichten, molarer Leitfähigkeit, Infrarot,¹H-NMR und TG-DTG-DTA-Untersuchungen charakterisiert.

     

Phosphino[tris(trimethylsilyl)methyl]Boranes and 2,4‐Bis[tris(trimethylsilyl)methyl]‐1,3,2,4‐diphosphadiboretanes [1]

The reaction of tris(trimethylsilyl)methylboron dihalides (Me₃Si)₃CBX₂ (X = Cl, F) with the lithium phosphides LiPHtBu and LiPHmes leads to the phosphinoboranes (Me₃Si)₃CBX‐(PHR), (Me₃Si)₃CB(PHR)₂ or the 1,3,2,4‐diphosphadiboretanes [(Me₃Si)₃CB(PR)]₂, depending on the ratio of the reagents, the reaction temperature and concentration. High dilution and low temperatures are required for the synthesis of (Me₃Si)₃CB(Hal)PHR ( 1–3 ) in order to prevent the formation of (Me₃Si)₃CB(PHR)₂ ( 4 and 5 ). The latter compounds are best prepared in a two step phosphination from (Me₃Si)₃CBHal₂ and LiPHR. At higher temperatures the four‐membered 1,3,2,4‐diphosphadiboretanes [(Me₃Si)₃CB(PR)]₂ 6 and 7 are the most stable compounds. On the other hand, compounds of type (Me₃Si)₃CB(Hal)PR₂, 8 and 9 , are thermally more stable than the monophosphinoboranes 1 – 3 . Phosphinoboranes of type (Me₃Si)₃CB(PR₂)₂ (R = tBu, mes) could not be prepared. NMR and mass spectral data are in accord with the monomeric nature of compounds 1 to 9 .     

Synthesis and reactions of [tris(trimethylsilyl)methyl]ethyl dichlorosilane

The crowded dichlorosilane TsiSiEtCl₂, (1), (Tsi = (Me₃Si)₃C) was prepared from the reaction between EtSiCl₃ and TsiLi, then it was reduced with LiAlH₄ to give TsiSiEtH₂, (2). The hydride (2) was then treated with two equivalents of ICl/CCl₄ or Br₂/CCl₄ to produce TsiSiEtI₂, (3), and TsiSiEtBr₂, (4), respectively. The reaction of compound (2) with one equivalent of ICl/CCl₄ gives TsiSiEtHI, (5). This product reacted with H₂O/dioxane in the presence of AgClO₄ or with dry MeOH to produce TsiSiEtHOH, (6), and TsiSiEtHOMe, (7), respectively. The compound (3) reacted with H₂O in DMSO/CH₃CN to give TsiSiEt(OH)₂, (8), and the compound TsiSiEtIOMe, (9), was prepared from the reaction of the compound (7) with ICl/CCl₄. When the dichloride (1) was treated with NaOMe/MeOH it gave (Me₃Si)₂CHSiEt(OMe)₂. It is suggested that the reaction proceeds through an elimination-addition mechanism. The dichloride (1) was also treated with KSCN, NaN₃ or NaOCN in CH₃CN to give S_N2 substitution products. All the new products were characterized by FTIR, ¹H NMR, and ¹³C NMR spectroscopy, mass spectrometry and elemental analysis.     

双[1,3-二(三甲硅基)环戊二烯基]四羰基二铁的反应性

题示化合物分子中的铁铁键被钠汞齐还原断裂, 生成相应的单核铁负离子, 后者分别与PhCOCl, PhCH~2Cl,ClCH~2COOC~2H~5, Ph~3SnCl 及Ph~2SnCl~2进行亲核取代反应,生成在铁原子上引入相应取代基的产物。题示化合物分别与卤素和二氯化汞反应, 生成铁铁键断裂的铁卤化物和铁氯汞化物。用X-射线测定了题示化合物与Ph~3SnCl反应生成产物的晶体和分子结构。     

Polymer synthesis by means of germylene and stannylene

Divalent group 14 metal species, a germylene(la) and a stannylene(lb), behaved as a comonomer(reductant monomer) in the copolymerization with p-benzoquinone derivatives(oxidant monomer)(“oxidation-reduction copolymerization”) and as an initiator for anionic monomers. The copolymerization took place without initiator at a lower temperature to give an alternating copolymer. N-phenyl-p-quinoneimine also behaved as a reactive oxidant monomer toward la and lb. These species have been shown to induce the polymerization of anionically polymerizable monomers such as methyl methacrylate, methacrylonitrile, and 4-vinylpyridine. Based on the mechanistic examination of the polymerization, a new alternating copolymerization between la and 2-cyclohexene-l-one has been developed to produce a copolymer having a metal-enolate structure, which involves the oxidation-reduction process during the copolymerization.     

Improvements in the preparation and use of [tris(trimethylsilyl)methyl]lithium

Improvements in the preparation and use of [tris(trimethylsilyl)methyl]lithium are described.