14596-92-0Relevant articles and documents
Laser-Induced Infrared Multiphoton Isomerization Reactions of 2,4- ans 1,3-Hexadienes
Buechele, James L.,Weitz, Eric,Lewis, Frederick D.
, p. 868 - 876 (1984)
Efficient and clean isomerization has been observed in the system consisting of the conjugated 2,4- and 1,3-hexadienes following infrared multiphoton excitaton of these species.Variations of both laser fluence and pressure of the added inert gas are seen to significantly effect branching ratios and yields.Where a competition exists between a low activation energy, low preexponential factor pathway and one with a high activation energy, high preexponential factor, an increase in fluence is seen to favor the latter pathway.An estimate of the degree of excitation in the molecule is obtainable from product branching ratios and inert gas quenching behavior.Photoacoustic measurements of energy input coupled with observation of product ratios indicate that the production of multiple products in a single laser pulse is compatible with a sequential isomerization mechanism which takes place in an almost vibrationally adiabatic fashion.Thermal and CW laser studies of hexadiene isomerization have been performed.Thermal studies yield rate constants and ΔH and ΔS for the various isomers.Thermal studies coupled with multiphoton studies have helped establish the isomerization pathway connecting the cis,trans-2,4- and trans-1,3-hexadiene isomers and have confirmed the other isomerization pathway in the system.The pathways for CW cw laser-induced isomerization have been studied.
Applications of PC(sp3)P iridium complexes in transfer dehydrogenation of alkanes
Bzier, David,Brookhart, Maurice
, p. 3411 - 3420 (2015/02/19)
Iridium ethylene complexes based on the PC(sp3)P pincer-type triptycene ligand have been synthesized. Complexes bearing various substituents on the phosphines have been investigated as catalysts in transfer dehydrogenation of alkanes. The complex 8a, which bears isopropyl groups, has demonstrated high stability and activity when used as a catalyst in the disproportionation of 1-hexene at 180 °C and in the transfer dehydrogenation of linear and cyclic alkanes with tert-butylethylene as a hydrogen acceptor at 200°C. A similar complex bearing a CH2NMe2 group, 33, allowed support of the catalyst on γ-alumina for operation in a heterogeneous mode.
Metal Catalysis in Organic Reactions. Part 13. The Reaction of 3-En-1-ynes with Trialkylalanes: Influence of Transition-metal Complexes
Caporusso, Anna Maria,Giacomelly, Giampaolo,Lardicci, Luciano
, p. 1900 - 1908 (2007/10/02)
The reaction between trialkylalanes and 3-alkyl-, or 4-alkyl-, or 3,4-dialkyl-but-3-en-1-ynes (1) lead to products which correspond to metallation, reduction, and carbalumination processes.The extent of such reactions, and the regio- and stereo-selectivity of the carbalumination, are dependent on the enyne used.A mechanism is proposed involving tautomeric equilibria among several α-unsaturated organoaluminium intermediates to explain the formation of the carbalumination products. In the presence of catalytic amounts of nickel and manganese complexes, 3-en-1-ynes (1), by reacting with tri-isobutylaluminium, are dimerized selectively in a 'head-to-tail' fashion to conjugated tetraenes having different structures in relation to the different nature of the transition-metal complex.The preparative aspect of these induced reactions is discussed, and, in the light of previous reports, some mechanistic considerations are presented.
