Nickel–Alkyl Complexes with a Reactive PNC-Pincer Ligand

Abstract

Based on previous work related to the design and application of rigid tridentate phosphine–pyridine–phenyl coordination offered by a PNC-pincer ligand upon cyclometalation to nickel, the synthesis, spectroscopic and solid state characterization and redox-reactivity of two NiII(PNC) complexes featuring either a methyl (2CH3) or CF3 co-ligand (2CF3) are described. One-electron oxidation is proposed to furnish C–C reductive elimination, as deduced from a combined chemical, electrochemical, spectroscopic and computational study. One-electron reduction results in a ligand-centered radical anion, as supported by electrochemistry, UV spectroelectrochemistry, EPR spectroscopy, and DFT calculations. This further attenuates the breadth of chemical reactivity offered by such PNC-pincer ligands.