Aromatic and aliphatic hydrocarbon hydroxylation a formally NiO oxidant.

The reaction of (NMe)[Ni(L)(OAc)] (1[OAc], L = 2,2',2''-nitrilo-tris-(-phenylacetamide); OAc = acetate) with 3-chloroperoxybenzoic acid (-CPBA) resulted in the formation of a self-hydroxylated Ni-phenolate complex, 2, where one of the phenyl groups of L underwent hydroxylation. 2 was characterised by UV-Vis, EPR, and XAS spectroscopies and ESI-MS. 2 decayed to yield a previously characterised Ni-phenolate complex, 3.

Synthesis and Characterization of a Masked Terminal Nickel-Oxide Complex.

In exploring terminal nickel-oxo complexes, postulated to be the active oxidant in natural and non-natural oxidation reactions, we report the synthesis of the pseudo-trigonal bipyramidal Ni complexes (K)[Ni (L )(DMF)] (1[DMF]) and (NMe ) [Ni (L )(OAc)] (1[OAc]) (L =2,2',2''-nitrilo-tris-(N-phenylacetamide); DMF=N,N-dimethylformamide; OAc=acetate). Both complexes were characterized using NMR, FTIR, ESI-MS, and X-ray crystallography, showing the L ligand to bind in a tetradentate fashion, together with an ancillary donor. The reaction of 1[OAc] with peroxyphenyl acetic acid (PPAA) resulted in the formation of [(L )Ni -O-H⋅⋅⋅OAc] , 2, that displays many of the characteristics of a terminal Ni=O species.

Reactivity Properties of Mixed- and High-Valent Bis(μ-Hydroxide)-Dinickel Complexes.

Despite their potential role in enzymatic systems, there is a dearth of hydroxide-bridged high-valent oxidants. We recently reported the synthesis and characterization of NiNi(μ-OH) () and Ni (μ-OH) () species supported by a dicarboxamidate ligand (,'-bis(2,6-dimethyl-phenyl)-2,2-dimethylmalonamide). Herein, we explore the oxidative reactivity of these species using a series of para-substituted 2,6-di--butyl-phenols (4-X-2,6-DTBP, X = -OCH, -CHCH, -CH, -C(CH), -H, -Br, -CN, and -NO) as a mechanistic probe.

Preparation and Characterisation of a Bis-μ-Hydroxo-Ni Complex.

Hydroxide-bridged high-valent oxidants have been implicated as the active oxidants in methane monooxygenases and other oxidases that employ bimetallic clusters in their active site. To understand the properties of such species, bis-μ-hydroxo-Ni complex (1) supported by a new dicarboxamidate ligand (N,N'-bis(2,6-dimethyl-phenyl)-2,2-dimethylmalonamide) was prepared. Complex 1 contained a diamond core made up of two Ni ions and two bridging hydroxide ligands.