Redox Non-Innocence of Nitrosobenzene at Nickel.

Nitrosobenzene (PhNO) serves as a stable analogue of nitroxyl (HNO), a biologically relevant, redox-active nitric oxide derivative. Capture of nitrosobenzene at the electron-deficient β-diketiminato nickel(I) complex [(i) Pr2 NNF6 ]Ni results in reduction of the PhNO ligand to a (PhNO)(./-) species coordinated to a square planar Ni(II) center in [(i) Pr2 NNF6 ]Ni(η(2) -ONPh). Ligand centered reduction leads to the (PhNO)(2-) moiety bound to Ni(II) supported by XAS studies. Systematic investigation of structure-reactivity patterns of (PhNO)(./-) and (PhNO)(2-) ligands reveals parallels with superoxo (O2 )(./-) and peroxo (O2 )(2-) ligands, respectively, and forecasts reactivity patterns of the more transient HNO ligand.