Electronic Effect of Ligands on the Stability of Nickel–Ketene Complexes

Electronically variant
(dppf)­Ni­(ketene) complexes were synthesized
and characterized to perform kinetic analysis on their decomposition
through a decarbonylation/disproportion process to Ni–CO complexes
and alkenes. Ligands containing electron-donating groups stabilized
such complexes, whereas an electron-withdrawing group was found to
destabilize them. Hammett analysis on the decomposition reaction revealed
the buildup of negative charges in the rate-determining step, which
corroborates past computational models.