52885-14-0Relevant articles and documents
Catalysis of hydrosilylation: Part XXXIV. High catalytic efficiency of the nickel equivalent of Karstedt catalyst [{Ni(η-CH2=CHSiMe2)2O} 2{μ-(η-CH2=CHSiMe2)2O}]
Maciejewski,Marciniec,Kownacki
, p. 175 - 181 (2007/10/03)
The nickel equivalent of Karstedt catalyst [{Ni(η-CH2=CHSiMe2)2O} 2{μ-(η-CH2=CHSiMe2)2O}] (1) appeared to be a very efficient catalyst for dehydrogenative coupling of vinyl derivatives (styrene, vinylsilanes, vinylsiloxanes) with trisubstituted silanes HSi(OEt)3, HSiMe2Ph. The reaction occurs via three pathways of dehydrogenative coupling, involving formation of an unsaturated compound as the main product as well as a hydrogenated olefin (DS-1) pathway, hydrogenated dimeric olefin (DS-2) and dihydrogen (DC), respectively. The reaction is accompanied by side hydrosilylation. Stoichiometric reactions of 1 with styrene and triethoxysilane, in particular synthesis of the bis(triethoxysilyl) (divinyltetramethyldisiloxane) nickel complex 3 and the first documented insertion of olefin (styrene) into Ni-Si bond of complex 3, as well as all catalytic data have allowed us to propose a scheme of catalysis of this complex reaction by 1.
Competitive dehydrogenative silylation and hydrogenative dimerization of vinyltriethoxysilane catalyzed by the [Ni(acac)2] + PPh3 system, intermediate and mechanistic implications
Marciniec,Maciejewski,Gulinski,Maciejewska,Duczmal
, p. 245 - 251 (2007/10/03)
[Ni(acac)C2H5(PPh3)] (C) has been shown to be an essential intermediate in the reaction between HSi(OC2H5)3 and vinyltrisubstituted silanes catalyzed by the system [Ni(acac)2] + PPh3 at room temperature, but only after oxygenation of the coordinated triphenylphosphine. The stoichiometric and catalytic reactions of complex C with the substrates lead to catalysed, competitive dehydrogenative silylation and hydrogenative dimerization of vinylsilane, which occur following insertion of the latter into Ni-H, Ni-Si ≡ and Ni-C bonds.
Catalysis of hydrosilylation. Part XXV. Effect of nickel(0) and nickel(II) complex catalysts on dehydrogenative silylation, hydrosilylation and dimerization of vinyltriethoxysilane
Marciniec, Bogdan,Maciejewski, Hieronim,Rosenthal, Uwe
, p. 147 - 152 (2007/10/02)
General catalysis by Ni(O) and Ni(II) phosphine and non-phosphine complexes of the competitive-consecutive reaction of vinyltriethoxysilane with triethoxysilane has been observed to give mainly products of dehydrogenative silylation and hydrogenative dimerization accompanied by products of regular hydrosilylation, disproportionation of substrates and secondary reactions of the product-bis(silyl)ethene.In an excess of vinylsilane, side reactions can be practically eliminated.Tertiary phosphine and phosphite ligands of nickel acetylacetonate (Ni(acac)2*2PR3) stop the consecutive reactions of bis(silyl)ethene but in the presence of ?-basic and bulky tricyclohexylphosphine the system catalyzes selectively the regular hydrosilylation of bis(silyl)ethene.Keywords: Nickel; Silicon; Hydrosilylation; Silane; Catalysis
Catalysis of hydrosilylation XXIII. Effect of substituents at silicon on unusual hydrosilylation of vinylsilanes catalysed by nickel acetylacetonate
Marciniec, Bogdan,Maciejewski, Hieronim
, p. 45 - 50 (2007/10/02)
Nickel acetylacetonate catalyses a competitive-consecutive reaction of trisubstituted silanes ((EtO)3SiH and Et3SiH) with a variety of vinyl-trisubstituted silanes, giving products of dehydrogenative silylation, hydrosilylation and hydrogenative oligimerization as well as of disproportionation of substrates and dehydrogenative silylation of bis(silyl)ethenes.The conversion, yield and selectivities of the reaction have been influenced by many factors such as electronic and steric effects of the substituents at silicon of both initial substrates, as well as by the vinyl:hydrosilane ratio, the temperature and the presence of dioxygen.
Catalysis of hydrosilylation. XX. Unusual reaction of vinyltriethoxysilane with triethoxysilane catalyzed by nickel acetylacetonate
Marciniec, Bogdan,Maciejewski, Hieronim,Mirecki, Janusz
, p. 61 - 67 (2007/10/02)
Nickel acetylacetonate is shown to be a catalyst of an unusual reaction of vinyltriethoxysilane with triethoxysilane involving formation of bis(silyl)ethene and bis(silyl)butanes as the main products accompanied by others of direct and dehydrogenative hydrosilylation, bis(silyl)ethane and ethylsilane as well as products of redistribution of triethoxysilane and formation of oligomers.The latter reaction is a consequence of consecutive oligomerization of bis(silyl)ethenes and other products.The effect of temperature, the concentration ratio of substrates and the catalyst, and other reaction conditions on the conversion and reaction yield led us to propose a scheme explaining the course of this competitive-consecutive reaction.
