404873-90-1Relevant academic research and scientific papers
Sterically demanding diphosphonite ligands - Synthesis and application in nickel-catalyzed isomerization of 2-methyl-3-butenenitrile
Van Der Vlugt, Jarl Ivar,Hewat, Alison C.,Neto, Samuel,Sablong, Rafael,Mills, Allison M.,Lutz, Martin,Spek, Anthony L.,Mueller, Christian,Vogt, Dieter
, p. 993 - 1003 (2007/10/03)
The synthesis of a novel class of sterically demanding diphosphonites 1-8, based on rigid backbones, is described. The starting materials are all commercially available and the methodology allows for a modular approach. All ligands have been fully characterized, including an X-ray crystal structure for compound 1, 4,5-bis{di[(2-terr-butyl)phenyl]phosphonito}-9,9-dimethylxanthene. The coordination of these diphosphonite ligands towards Ni(II) and Ni(0) precursors is investigated, both by NMR spectroscopy as well as X-ray crystallography and compared with the behaviour of diphosphine ligands such as Xantphos. The molecular structure for complex 9, trans-[NiBr2(1)] is described in detail. The nickel-catalyzed isomerization of 2-methyl-3- butenenitrile to 3-pentenenitrile is studied, a relevant step in the industrially important hydrocyanation of butadiene (the DuPont adiponitrile process). Good activities and selectivities to the desired 3-pentenenitrile are obtained in this reversible C-C bond activation reaction.
Method for hydroformylation, xanthene-bridged ligands and catalyst comprising a complex of said ligands
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Page/Page column 11, (2008/06/13)
In a process for the hydroformylation of ethylenically unsaturated compounds, at least one complex of a metal of transition group VIII. with at least one phosphorus-, arsenic- or antimony-containing compound as ligand is used as hydroformylation catalyst, where the compound used as ligand in each case comprises two groups which comprise a P, As or Sb atom and at least two further hetero atoms and are bound to a xanthene-like molecular framework. New compounds of this type and catalysts which comprise at least one complex of a metal of transition group VIII. with at least one such compound as ligand are also provided.
