Aromatic and aliphatic hydrocarbon hydroxylation via a formally Ni^IVO oxidant

Abstract

The reaction of (NMe4)2[NiII(LPh)(OAc)] (1[OAc], LPh = 2,2',2''-nitrilo-tris-(N-phenylacetamide); –OAc = acetate) with 3-chloroperoxybenzoic acid (m-CPBA) resulted in the formation of a self-hydroxylate NiIII-phenolate complex, 2, where one of the phenyl...

The elusive active species in nickel(ii)-mediated oxidations of hydrocarbons by peracids: a NiII–oxyl species, an aroyloxy radical, or a NiII–peracid complex?

“…Conversion of the OH group of the Ni III –OH species to a stable H 2 O molecule by abstracting a hydrogen atom from hydrocarbon C–H bonds releases large exothermicity, which might in turn promote the H-abstraction process, like the H-abstraction process by a Ni III –F species. 53 The capability of C–H activation by nickel–oxygen species was also reported by McDonald et al 54–58 For the transition state with m CBA˙, the O–H and C–H distances are 1.422 Å and 1.201 Å, respectively, and the C–H–O angle is 169.3°. For the transition state with the Ni III –OH species, the O–H distance is 1.555 Å, C–H is 1.162 Å, and the C–H–O angle is 165.5°.…”

Unraveling the Mechanism of Hydrogen Atom Transfer by a Nickel-Hypochlorite Species and the Influence of Electronic Effects

“…10,11 Despite these published reports, details about the mechanism operating behind these transformations are unclear. Quite often, the involvement of (high-valent) nickel-oxygen species has been postulated, 12 but examples of well-identified species with oxidizing abilities have been scarcely described. In this line, finding appropriate systems for the entrapment of these nickel-oxygen species and studying their reactivity are especially appealing to design better catalysts.…”