57603-40-4Relevant articles and documents
Nickel-catalyzed transfer hydrogenation of ketones using ethanol as a solvent and a hydrogen donor
Castellanos-Blanco, Nahury,Arévalo, Alma,García, Juventino J.
, p. 13604 - 13614 (2016)
We report a nickel(0)-catalyzed direct transfer hydrogenation (TH) of a variety of alkyl-aryl, diaryl, and aliphatic ketones with ethanol. This protocol implies a reaction in which a primary alcohol serves as a hydrogen atom source and solvent in a one-pot reaction without any added base. The catalytic activity of the nickel complex [(dcype)Ni(COD)] (e) (dcype: 1,2-bis(dicyclohexyl-phosphine)ethane, COD: 1,5-cyclooctadiene), towards transfer hydrogenation (TH) of carbonyl compounds using ethanol as the hydrogen donor was assessed using a broad scope of ketones, giving excellent results (up to 99% yield) compared to other homogeneous phosphine-nickel catalysts. Control experiments and a mercury poisoning experiment support a homogeneous catalytic system; the yield of the secondary alcohols formed in the TH reaction was monitored by gas chromatography (GC) and NMR spectroscopy.
Nickelalactones with an allyl subunit-the effect of penta-coordination on structures and stability
Freund, Robert R. A.,Goerls, Helmar,Langer, Jens
, p. 13988 - 14000 (2014/11/08)
A series of allyl modified nickelalactone derivatives of the general formula [(L)nNi{CH2C(CH3)C(CH 3)CH2COO}] was synthesized via ligand exchange reactions in order to investigate the influence of the neutral ligand L on the structure and stability of these complexes. While the square planar 1,8-diazabicyclo[5,4, 0]undec-7-ene ligated derivative 1 is stable in the solid state and in solution at ambient temperature, the use of the chelating ligands 6-diphenylphosphino-1, 8-diazabicyclo[5.4.0]undec-7-ene, 1,1-bis(dicyclohexylphosphino)methane and 1,2-bis(dicyclohexylphosphino)ethane (dcpe) led to square pyramidal derivatives 2, 4, and 5 with a novel ligand arrangement. In solution, these derivatives are fluxional and show increasing tendencies in the order 2 2 and zero-valent nickel complexes. During the investigation of 5, the tetrahedral complex [(dcpe)2Ni] (6) and the trigonal planar derivative [(dcpe)Ni(dmbd)] (7) were observed as predominant decomposition products. In the case of the application of 1,1-bis(diphenylphosphino)methane as a neutral ligand, a dinuclear nickelalactone species [(μ-dppm)(Ni{CH 2C(CH3)C(CH3)CH2COO})2] (3) was isolated in which the two nickel atoms realize different coordination geometries (SP-4 and SPY-5) in the solid state. The complexes were characterized by NMR techniques, single crystal X-ray diffraction measurements and infrared spectroscopy.
Synthesis and reactions of nickel(0) η2-cyclohexyne complexes and X-ray crystal structure of Ni(η2-C6H8)(C6H 11)2PCH2CH2P(C6H 11)2
Bennett, Martin A.,Johnson, Julian A.,Willis, Anthony C.
, p. 68 - 74 (2008/10/08)
Reduction of 1,2-dibromocyclohexene with 1% sodium amalgam in the presence of Ni(η2-C2H4)L2 gives cyclohexyne nickel(O) complexes Ni(η2-C6H8)L2 [L2 = 2PPh3 (1), dcpe (2), 2PEt3 (3); dcpe = 1,2-bis(dicyclohexylphosphino)ethane, Cy2PCH2CH2PCy2], which are structurally similar to, but less stable than, the corresponding platinum(O) compounds. The crystal structure of 2 has been determined. The molecule contains a nickel atom bound to η2-cyclohexyne [Ni-C(1) = 1.875(4) A?, Ni-C(2) = 1.867(4) A?] and to dcpe [Ni-P(1) = 2.139-(1) A?, Ni-P(2) = 2.138(1) A?]. The geometry is close to trigonal planar if the midpoint of the coordinated triple bond is regarded as occupying one coordination site, and the C=C distance [1.272(5) A?] is slightly less than that in Pt(η2-C6H8)(PPh3)2 [1.297(8) A?]. Complex 2 reacts with methyl iodide and with CO2 to give insertion products containing nickel(II), NiI(2-MeC6H8)(dcpe) (7) and Ni{C6H8C(O)O}(dcpe)(9), respectively. Dimethyl acetylenedicarboxylate inserts into the Ni-C σ-bond of 9 to give a seven-membered nickelacycle Ni{C(CO2-Me)=C(CO2Me)C6H 8C(O)C-(dcpe) (10).
