3681-30-9Relevant articles and documents
Reaction of Hydrogen Peroxide with Organosilanes under Chemical Vapour Deposition Conditions
Moore, Darren L.,Taylor, Mark P.,Timms, Peter L.
, p. 2673 - 2678 (2007/10/03)
When a stream of vapour at low pressure which contained a mixture of H2O2 with an organosilane, RSiH3 (R = alkyl or alkenyl), impinged on a silicon wafer, deposition of oxide films of nominal composition RxSiO(2-0.5x), where x 3 or higher alkenyl groups. or higher alkenylgroups. Possible mechanism for the Si-C bond cleavage reaction are discussed, with energetic rearrangement of radical intermediates of type Si(H)(R)(OOH)' being favoured.
Evidence for the activation of unstrained carbon-carbon bonds by bare transition-metal ions M+ (M = Fe, Co) without prior C-H bond activation
Karrass, Sigurd,Schwarz, Helmut
, p. 2034 - 2040 (2008/10/08)
The metastable ion (MI) decompositions of RNH2/M+ complexes (R = (C2H5)2CHCH2, C2H5C(CH3)2CH2; M - Fe, Co) in the gas phase have been studied by tandem mass spectrometry with a four-sector instrument of BEBE configuration. The analyses of the MI spectra of isotopically labeled complexes uncover processes which inter alia demonstrate that the loss of C4H8 corresponds to a reaction in which site-specific oxidative addition of an unstrained C-C bond to the anchored transition-metal ion M+ takes place without prior C-H bond activation. The intramolecular methyl migration preceding the elimination of C4H8 is subject to a secondary kinetic isotope effect of kH/kD = 1.33 for M+ = Fe+ and kH/kD = 1.15 for M+ = Co+ per D atom. Additional processes observed correspond to the generation of molecular hydrogen, methane, ethylene and ethane. All reactions are highly specific, and mechanisms are suggested that are in keeping with the labeling data. For example, both H2 and C2H4 are formed via remote functionalization involving the ω/ (ω - 1) positions of the ethyl side chain of the amines. Ethane contains an intact ethyl group, and one hydrogen is provided via specific β-hydrogen transfer which does not involve the chemically activated CH2NH2 group. This methylene group is also inert with regard to the reductive elimination of methane from CH3CH2C(CH3)2CHNH 2/Co+. According to the labeling experiments, the intermediate from which CH4 is lberated contains an intact CH3 group that originates from the quaternary carbon center; the missing hydrogen atom is provided to roughly the same amount by both the second CH3 group of C(2) and the CH2 unit of the ethyl group. Again, the -CH2NH2 part does not serve as a hydrogen source for CH4.
Hydrogenation of Ethylene on Metal Electrodes. Part 5. Reduction of Light Ethylene on Pt in Deuteroperchloric Acid Solution and the Dual-pathway Mechanism
Fujikawa, Keikichi,Kita, Hideaki,Sato, Shinri
, p. 3055 - 3072 (2007/10/02)
Electroreduction of light ethylene on a platinum electrode was conducted in a heavy-water solution of deuteroperchloric acid.Deuterium-atom distributions in the product, ethane, support the previous conclusion that ethylene diffusion is rate-controlling at potentials less positive than ca. 100 mV, whereas the surface reaction is rate-controlling at more positive potentials where the Tafel line holds.The D-atom distribution in the latter potential region reveals double maxima at - and -ethanes.This distribution is explained by the dual-pathway mechanism which assumes two reaction rates for the step C2H4(a) + H(a) C2H5(a).The difference in the reaction rate will be attributed to the difference in the adsorption state of C2H4(a) but not of H(a), since only the weakly adsorbed hydrogen atoms are active in the hydrogenation.Reduction of light ethylene with D2 on platinum in deuteroperchloric acid solution gives the same results.A computer simulation based on the above mechanism can reproduce quantitatively not only the present distributions but also others given in the literature, even those observed for the gas-phase heterogeneous reduction.
