- Synthesis and characterisation of novel zirconium(IV) derivatives containing the bis-amido ligand SiMe2(NRR′)2
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The silicon compounds SiMe2(NRR′)2 [NRR′ = NMe2 (1), NEt2 (2), NC4H8 (3), NHEt (4), NHiPr (5), NHtBu (6), NMeBu (7)] have been synthesised via aminolysis of the dichloro species SiMe2Cl 2 and their ligating ability has been investigated towards zirconium(IV). The dimer zirconium compound {Zr[(NiPr) 2SiMe2]2}2 (8) has been synthesised by reacting ZrCl4 with the lithium salt Li2[(N iPr)2SiMe2] and its molecular structure has been determined in the solid state by X-ray diffraction analysis. The reaction of ZrCl4 with SiMe2(NRR′)2 yields the Lewis adducts ZrCl4[(NRR′)2SiMe2] [NRR′ = NMe2 (10), NC4H8 (11), NHEt (12), NHiPr (13), NHtBu (14), NMeBu (15)]. On the other hand, the mixed amido derivative Zr(NMe2)3(NHMe)[(N′Bu) SiMe2(NH′Bu)] (9) has been obtained from the reaction of Zr(NMe2)4 with SiMe2(NHtBu) 2. The solution molecular structure and dynamics of the zirconium derivatives have been elucidated by 1D and 2D multinuclear NMR spectroscopy.
- Passarelli, Vincenzo,Benetollo, Franco,Zanella, Pierino,Carta, Giovanni,Rossetto, Gilberto
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- Process for preparing polyisocyanato/polyisocyanurates by catalytic cyclotrimerization of polyisocyanates
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Polyisocyanurate/polyisocyanates of enhanced stability are prepared by partial catalytic cyclotrimerization of a polyisocyanate in the presence of a catalytically effective amount of an aminosilyl catalyst and wherein the cyclotrimerization reaction is terminated when a predetermined desired amount of isocyanurate groups has been attained, by adding to the reaction mixture, after the cooling thereof to a temperature of below 50° C., a reaction terminating amount of an organic catalyst deactivating compound comprising at least one free hydroxyl moiety, or the reaction product of such hydroxylated organic catalyst deactivating compound with an isocyanate.
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- Complexation and Exchange Reactions of some Dimethylamino-substituted Group 4 Compounds
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Reactions of CH2(NMe2)2, (1), SiMe2(NMe2)2, (2), (cp=η-cyclopentadienyl), (3), and , (4), with covalent metal halides MCl4 (M=Ti,Zr,Si,Ge,or Sn) and MCl3 (M=Ti,V,or Cr) fall into two categories: (a) N-donor chelation leading to complex formation and (b) halide-NMe2 exchange.Compound (1) gives 1:1 complexes with MCl4 (M=Ti or Sn) and 2:1 complex with VCl3.Compound (2) provides 1:1 complexes with MCl4 (M=Ti,Zr,Hf, or Sn).The decomposition of TiCl4*SiMe2(NMe2)2 --> invariably occurs in both the solid state and solution.There is no reaction of (2) with metal(III) chlorides.With MCl4 (M=Si or Ge 'scrambling' reactions involving halide-NMe2 exchange occur and these have been monitored by 1H n.m.r. spectroscopy.Reactions of (3) and (4) with MCl4 (M=Si,Ge,Sn,Ti,Zr,or Hf) consistently feature halide-NMe2 exchange rather than adduct formation.All complexes have been characterised by analytical and spectroscopic (1H n.m.r. and i.r.) investigations.
- Wade, Steven R.,Willey, Gerald R.
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p. 1264 - 1267
(2007/10/02)
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- Chloraminosilanes II. Preparation and spectroscopic studies on alkyl-(dimethylamino)chlorosilanes
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Several new compounds containing both chloro and dimethylamino groups linked to silicon have been prepared. The general method involved reacting a solution of the appropriate polychlorosilane in ether at ca. - 50° with a chilled ethereal solution of dimethylamine. Prepared in this fashion were CH3Si(NMe2)Cl2, CH3Si(NMe2)2-Cl, PhSi(NMe2)Cl2, PhSi(NMe2)2Cl, CH3(H)Si(NMe2)Cl, (CH3)2Si(NMe2)Cl, CH2CH(CH3)Si(NMe2)Cl, and Ph2Si(NMe2)Cl. Comparison of the spectra of these compounds with those in the perhalo and peramine series showed that replacement of NMe2 for Cl resulted in an upfield shift of the resonances of the other groups linked to silicon, a shift which parallels that observed upon substitution of CH3 for Cl. The relationship of ν(SiH) in the IR and δ(SiH) in the NMR spectra was linear.
- Washburne,Peterson Jr.
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