Reductive elimination of benzonitrile from cyanophenyl complexes of nickel(II). III. Reactions of [cyano-(phenyl)bis(triethylphosphine)nickel(II)] with triethyl-phosphite. General reaction mechanism.

The kinetics of the elimination of C6H5CN in the reaction of Ni(CN)(C6H5)-[P(C2H5)3]2 with P(OC2H5)3 have been studied in toluene at 15°C. The results and the rate law show that the elimination mainly takes place by intramolecular decomposition of the 4-coordinate Ni(CN)(C6H5)[P(OC2H5)3]2 formed in initial substitution steps. A minor contribution to the formation of C6H5CN comes from the 5-coordinate species Ni(CN)(C6H5)[P(C2H5)3][P(OC2H5)3]2. The intimate mechanism of these reactions, involving splitting or formation of C—CN bonds in cyanophenyl complexes, is discussed in terms of the peculiar bonding properties of the CN group.