197455-55-3Relevant academic research and scientific papers
Nickel-catalyzed alkylation and transfer hydrogenation of α,β-unsaturated enones with methanol
Castellanos-Blanco, Nahury,Flores-Alamo, Marcos,Garcia, Juventino J.
, p. 680 - 686 (2012/04/10)
Complexes of the type [{(dippe)Ni} ( 2-Cα,Cβ- 1,4-dien-3-one)] (dippe = 1,2-bis(diisopropylphosphino)- ethane); n= 1, 2; enone = aromatic 1,4-pentadien-3-ones) were synthesized. The "[(dippe)Ni]" moiety derived from [(dippe)Ni(-H)]2 2-coordinated to the C,C double bonds of the corresponding α,β-unsaturated enone and was fully characterized using a variety of spectroscopic techniques, for instance, single-crystal X-ray diffraction, nuclear magnetic resonance (NMR), and mass spectrometry. The complexes were assessed in a catalytic transfer hydrogenation process using methanol (CH3OH) as a hydrogen donor. This alcohol turned out to be a very efficient reducing and alkylating agent of 1,4- pentadien-3-ones, under neat conditions. The current methodology allowed the selective reduction of C=C bonds in α,β- unsaturated enones to yield enones and saturated ketones by a homogeneous catalytic pathway, whereas by a heterogeneous pathway, the process leads to the formation of mono- and dimethylated ketones. In the latter case, the occurrence of nickel nanoparticles in the reaction media was found to participate in the catalytic alkylation of such dienones.
Mechanistic insights on the hydrodesulfurization of biphenyl-2-thiol with nickel compounds
Torres-Nieto, Jorge,Brennessel, William W.,Jones, William D.,Garcia, Juventino J.
, p. 4120 - 4126 (2009/09/05)
The reactivity of the nickel(I) dimer [(dippe)Ni(μ-H)]2 (1) with biphenyl-2-thiol was explored with the aim of clarifying the key step of sulfur extrusion during the hydrodesulfurization process using dibenzothiophene (DBT). These reactions were monitored by variable temperature NMR experiments which allowed the complete characterization and isolation of [(dippe) 2Ni2(μ-H)(μ-S-2-biphenyl)] (3). The latter compound evolves to the terminal nickel-hydride [(dippe)Ni (η1-C-2- biphenyl)(H)] (4) and transient [(dippe)NiS] (5), to ultimately yield [(dippe)2Ni2(w-S)] (2) and biphenyl as the resulting HDS products. The reactivity of 1 and biphenyl-2-thiol was examined using different ratios of reactants, which allowed preparation of [(dippe)Ni(η1-S-biphenyl- 2-thiolate)2](6) whenusing an excess of this substrate. The reactivity of 6 with 1 was addre ssed, yielding compound 2 and an equivalent amount of biphenyl.
Cleavage of carbon-carbon bonds in alkyl cyanides using nickel(0)
Garcia, Juventino J.,Arevalo, Alma,Brunkan, Nicole M.,Jones, William D.
, p. 3997 - 4002 (2008/10/09)
The reaction of the complex [(dippe)NiH]2 (1) with a variety of alkyl cyanides afforded nickel(O) compounds of the type [(dippe) Ni(η2-RCN)], where R = Me, Et, Pr, iPr, tBu, cyclopropyl, cyclobutyl, adamantyl (2-9, respectively). When compounds 2-9 were warmed to yield oxidative addition products, the thermal reaction proceeded only in the case of 2 to produce [(dippe)Ni(Me)(CN)] (10). Photochemical activation did produce oxidative addition products from compounds 2-8, which rapidly evolved to the β-elimination products of the organic moiety in most cases and to the formation of [(dippe)Ni(CN)2] (11). Reaction of 1 with acetonitrile in the presence of BPh3 gives [(dippe)Ni(η2-MeCNBPh3)] (12), which does not undergo thermal C-CN cleavage upon heating. X-ray crystal structures are reported for 10-12.
