7747-99-1Relevant articles and documents
A NMR method for the analysis of mixtures of alkanes with different deuterium substitutions
Loaiza, Alfonso,Borchardt, Dan,Zaera, Francisco
, p. 2481 - 2493 (2007/10/03)
13C NMR at 125.76 MHz with 1H and 2H decoupling, 2H NMR at 76.77 MHz with 1H decoupling, and 1H NMR at 500.14 MHz with 2H decoupling were employed as analytical tools to study the complex mixtures of deuterated ethanes resulting from the catalytic H-D exchange of normal ethane with gas-phase deuterium in the presence of a platinum foil. Reference samples consisting of 1:1 binary mixtures of pure normal ethane and ethane-dn (n = 1-6) were used to identify the peak positions in the 13C, 2H, and 1H NMR spectra due to each individual isotopomer, and the effect of isotopic substitution on the chemical shifts was determined in each case. While the NMR of all three nuclei worked well for the identification of the individual components of the 1:1 standard mixtures, both 1H and 2H NMR suffered from inadequate resolution when studying complex reaction mixtures because of the broadening of the lines due to 1H-1H (1H NMR) and 2H-2H (2H NMR) couplings. 13C NMR was therefore determined to be the method of choice for the quantitative analysis of the reaction mixtures. Using the 13C NMR results, a correlation that takes into account the primary and secondary isotope substitution effects on chemical shifts was deduced. This equation was used for the identification of the individual components of the mixtures, and integration of the individual observed resonances was then employed for quantification of their composition. This study shows that 13C NMR with 1H and 2H decoupling is a viable procedure for studying mixtures of deuterated ethanes. Furthermore, the additivity of the isotopic effects on chemical shifts and the transferability of the values obtained with ethane to other molecules makes this approach general for the analysis of other isotopomer mixtures.
Surface Far-Ultraviolet Photochemistry of Ethyl Chloride on GaAs(1000)
Liberman, Vladimir,Nooney, Matthew G.,Amata, Richard J.,Martin, Richard M.
, p. 2261 - 2269 (2007/10/02)
The photoinduced dissociation at 193 nm of monolayer ethyl chloride (EtCl) was studied on the Ga-rich GaAs(100) (8x2)Ga surface at 90 K.Photodepletion of EtCl is efficient, with a cross section of 6 x 10-19 cm2.Sixty percent of the EtCl molecules depleted by irradiation give ethyl groups bonded to the surface.The ethyl groups are stable up to ca. 500 K, which is the onset of thermal desorption of the products.The thermal desorption products are C2H4, C2H5, C2H6, H2 and GaCl.The hydrocarbon product distribution is approximately 70percent C2H4, 20percent C2H6, and 10percent C2H5 radicals.Experiments with CD3CH2Cl provide evidence that ethylene is formed by β-hydride elimination.The zero-coverage first-order kinetic parameters for this reaction are approximately Ea = 100 kJ/mol and A = 4.4 x 107 s-1.Comparison with the gas-phase photodissociation cross section indicates that the photodepletion is primarily due to substrate-mediated processes rather than to direct photodissociation of EtCl.The most probable mechanism involves photogenerated electron transport to the surface followed by electron dissociative attachment to EtCl.
Reactions of Metal-Metal Multiple Bonds. 8. Forming Mo-Mo Quadruple Bonds by Reductive Elimination (Alkyl Group Disproportionation) in the Reactions of 1,2-Mo2R2(NMe2)4 Compounds (M*M) with Carbon Dioxide and 1,3-Diaryltriazines
Chetcuti, M. J.,Chisholm, M. H.,Folting, K.,Haitko, D. A.,Huffman, J. C.
, p. 2138 - 2146 (2007/10/02)
Addition of CO2 and 1,3-diaryltriazines to 1,2-Mo2R2(NMe2)4 compounds (M*M), where R = CH3 and CH2Si(CH3)3, yields Mo2R2(O2CNMe2)4 and Mo2R2(NMe2)2(ArN3Ar)2 compounds, respectively, with retention of the Mo*Mo bond, whereas related reactions, where R = C2
