15629-93-3Relevant articles and documents
A broadly applicable strategy for entry into homogeneous nickel(0) catalysts from air-stable nickel(II) complexes
Standley, Eric A.,Smith, Stacey J.,Mueller, Peter,Jamison, Timothy F.
supporting information, p. 2012 - 2018 (2014/05/20)
A series of air-stable nickel complexes of the form L2Ni(aryl) X (L = monodentate phosphine, X = Cl, Br) and LNi(aryl)X (L = bis-phosphine) have been synthesized and are presented as a library of precatalysts suitable for a wide variety of nickel-catalyzed transformations. These complexes are easily synthesized from low-cost NiCl2·6H2O or NiBr 2·3H2O and the desired ligand followed by addition of 1 equiv of Grignard reagent. A selection of these complexes were characterized by single-crystal X-ray diffraction, and an analysis of their structural features is provided. A case study of their use as precatalysts for the nickel-catalyzed carbonyl-ene reaction is presented, showing superior reactivity in comparison to reactions using Ni(cod)2. Furthermore, as the precatalysts are all stable to air, no glovebox or inert-atmosphere techniques are required to make use of these complexes for nickel-catalyzed reactions.
Homogeneous hydrogenation and isomerization of 1-octene catalyzed by nickel(II) complexes with bidentate diarylphosphane ligands
Mooibroek, Tiddo J.,Wenker, Erica C. M.,Smit, Wietse,Mutikainen, Ilpo,Lutz, Martin,Bouwman, Elisabeth
, p. 8190 - 8201 (2013/08/23)
A systematic library of 24 nickel(II) complexes with bidentate diphosphane ligands was synthesized, and the solid-state structures of five of them were determined with X-ray crystallography. The compounds C1-C3 are common P 2NiIIX2-type complexes, while C4 contains a unique [P2NiII(NH3)(OAc)]+ square-planar structure with a P2NO donor set and C5 constitutes a rare [(P2NiII)2(μ-OH)2] 2+ dinuclear compound. The catalytic activity of all complexes was tested in the hydrogenation and/or isomerization of 1-octene in a CH 2Cl2/CH3OH reaction medium. Catalyst precursors bearing ligands with o-alkoxy aryl rings selectively hydrogentate 1-octene to n-octane, while catalytic systems comprising ligands without the o-alkoxy functionality selectively isomerize the substrate to a mixture of internal alkenes, mostly cis- and trans-2-octene. The conversion is enhanced by equipping the ligand aryl rings with electron-donating alkoxy groups, by increasing the steric bulk of the backbone and/or the aryl rings, by employing relatively noncoordinating anions, and by adding a base as the cocatalyst. Using the compound [Ni(L3X)I2] as the catalyst precursor and upon application of standard hydrogenation conditions, full conversion of the substrate was achieved in 1 h to isomerization products only (TON = 1940). When a catalytic amount of the base is added, a similar result is obtained even in the absence of H2. A maximum TON of 4500 in 1 h with 96% selectivity for n-octane was achieved by employing [Ni(oMeO-L3X)(NH3)(OAc)]PF6 as the catalyst precursor.
