1446141-20-3Relevant academic research and scientific papers
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)
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.
