Four- and five-coordinate CO insertion in the copolymerization of carbon monoxide and olefins catalyzed by diphosphine nickel(II) complexes: A dynamical density functional study

We have carried out a theoretical study of the migratory insertion step in the cationic Ni(II) [(dppp)Ni(CH3)(CO)]- complex by means of both static and dynamic density functional methods to shed light on the mechanistic aspects of the migratory insertion and in particular on the role played by five-coordinate species. We find the addition-insertion pathway, taking place via a five-coordinate complex, to be thermodynamically and kinetically favored, with a highest energy barrier of 7.9 kcal mol-1, in agreement with the experimental data. Dynamics simulations have shown that the migratory insertion reaction takes place by a methyl attack on the resting carbonyl group.