DFT Calculations of the Isomerization of 2-Methyl-3-butenenitrile by [Ni(bisphosphine)] in Relation to the DuPont Adiponitrile Process

The isomerization of 2-methyl-3-butenenitrile (2M3BN) carried out by [Ni(dippe)H](2) can follow either a C-CN activation pathway to form the linear product 3-pentenenitrile (3PN) or a C-H activation pathway to give the branched olefin product 2-methyl-2-butenenitrile (2M2BN). Both pathways have been studied by DFT calculation methods, and the results match well with those observed in stoichiometric experiments. A detailed mechanism has been proposed and tested on several other model bisphosphine ligands to investigate the bite angle and electronic effects on the selectivity of nickel bisphosphine catalysts.