Divergent Reactivity of CO2 and CO and Related Substrates at the Nickel Carbon Double Bond of (PCcarbeneP)Ni(II) Pincer Complexes

The addition of carbon monoxide (CO), carbon dioxide (CO2) and isoelectronic isocyanide and isocyanates to the nickel carbene bond in PCcarbeneP pincer complexes is reported. For CO and CNR, irreversible group transfer reactions are observed, while for CO2, a reversible 2+2 addition to the carbene moiety occurs. The course of the CO and CO2 reactions are strongly affected by the nature of the PCcarbeneP pincer ligand framework and a new more rigid ligand based on a 10,10-dimethyl-9,10-dihydroanthracene core was designed in order to study these reactions, illustrating the profound effect of small changes in ligand structure on reaction outcomes.