O/C Bond Cleavage of CO₂ by Ni^I

Reaction of (PNP)Ni, where PNP is [(tBu2PCH2SiMe2)2N]−1, with CO2 occurs rapidly even at −60 °C to form exclusively the product of transposition of the amide N and one CO2 oxygen: [(tBu2PCH2SiMe2)2O]Ni(NCO). DFT(B3LYP) evaluation of several candidate intermediates for breaking two Si/N and one C/O bond and forming two Si/O and one N/C bond reveal species at and below the energy of the separated particles, and establish the location of the spin densities in each.