Accessing Ni(0) to Ni(IV) via nickel-carbon-phosphorus bond reorganization

Two-electron oxidation of a (NiPh)-Ph-II(PCP) pincer complex initiates phosphine ligand insertion, generating an eta(6)-arylphosphonium moiety coordinated to Ni-II. The reaction is fully reversible under reducing conditions. X-ray crystallography, NMR/EPR spectroscopy, electrochemistry, and DFT calculations support the proposed Ni-C-P bond reorganization mechanisms, which access oxidation states from Ni-0 to Ni-IV.