2813-62-9Relevant articles and documents
Nuclear spin isomers of ethylene: Enrichment by chemical synthesis and application for NMR signal enhancement
Zhivonitko, Vladimir V.,Kovtunov, Kirill V.,Chapovsky, Pavel L.,Koptyug, Igor V.
supporting information, p. 13251 - 13255 (2014/01/06)
Taking CH2CH2 for a spin: Enrichment of the nuclear spin isomers of ethylene was achieved by a catalytic reaction of acetylene with parahydrogen (see scheme). The spin isomers were used for NMR signal enhancement, both with and without subjecting them to a chemical reaction. The interconversion times of the nuclear spin isomers were evaluated at ambient pressure, thus revealing extremely long-lived spin states with lifetimes of (1000±400)s.
Catalytic behavior of a polynuclear Mg-Mo complex and nitrogenase active site (FeMoco) isolated from the enzyme in reactions with C2H 2, N2, and CO: A comparative study
Bardina,Bazhenova,Petrova,Shilova,Shilov
, p. 793 - 801 (2007/10/03)
In order to identify common and distinctive features in the catalytic behavior of natural and artificial nitrogen-fixation clusters, the kinetics of the catalytic reduction of C2H2 in the presence of Mg-Mo-cluster (1) was investigated and compared with the kinetics of acetylene reduction catalyzed by the cluster FeMoco (2) isolated from the enzyme nitrogenase we studied previously. The reactions were conducted in the presence of Zn/Hg and Eu/Hg as reducing agents and PhSH and C6F5SH as proton donors, i.e., under the same conditions as had been used in the case of 2. Both polynuclear Mg-Mo-complex and the europium amalgam-reduced FeMoco have multiple interdependent binding sites for substrates and/or inhibitors. Carbon monoxide inhibits the acetylene reduction much less efficiently in systems with cluster 1 than in systems with cluster 2, although the type of inhibition is mixed in both systems: CO binds to multiple sites of the cluster and affects both C2H2 complexation to the reduced cluster and decomposition of the catalyst-substrate complex to give the products. Unlike isolated FeMoco, the Mg-Mo-cluster efficiently catalyzes the reduction of molecular nitrogen. The reaction is greatly inhibited by acetylene, while no inhibiting effect of N2 is observed in acetylene reduction, as was found earlier for a system with the natural cluster as the catalyst. Springer Science+Business Media, Inc. 2006.
Stereochemistry of the thermal conversion of 1-vinyl-2,3-cis-dideuteriocyclobutane to butadiene and 1,2-dideuterioethylenes
Lewis, David K.,Hutchinson, Avery,Lever, Steven J.,Spaulding, Eric L.,Bonacorsi Jr., Samuel J.,Baldwin, John E.
, p. 233 - 237 (2007/10/03)
This study has examined the stereochemistry of the decomposition at 900-1000 K in a single-pulse shock tube of 1-vinyl-2,3-cis-dideuteriocyclobutane to ethylenes and buta-1,3-dienes. The deuterated ethylenes formed during the decomposition, CHD=CH2, (E)-CHD=CHD, and (Z)-CHD=CHD, were quantified via two independent techniques, FTIR and IR absorption spectroscopy using a tunable diode laser spectrometer. The results of both analyses indicated that equal amounts of (E)-CHD=CHD and (Z)-CHD=CHD were formed from the cis-labeled reactant. In an earlier shock tube study of the decomposition at 1000-1200 K of two deuterium-labeled cyclohexenes to ethylenes plus buta-1,3-dienes, a pathway via a vinylcyclobutane intermediate was implicated in a significant fraction of the decomposition events; the measured ratios of (E)-CHD=CHD to (Z)-CHD=CHD in that study were consistent with a complex mechanistic model in which the stereochemistry of deuterium labels in the cyclohexene reactant was lost in ethylene products formed via vinylcyclobutane. The present results provide additional support for that model.
