Activation of Dioxygen at a Lewis Acidic Nickel(II) Complex: Characterization of a Metastable Organoperoxide Complex

Abstract

In metal‐mediated O2 activation, nickel(II) compounds hardly play a role, but recently it has been shown that enzymes can use nickel(II) for O2 activation. Now a low‐coordinate Lewis acidic nickel(II) complex has been synthesized that reacts with O2 to give a nickel(II) organoperoxide, as proposed for the enzymatic system. Its formation was studied further by UV/Vis absorption spectroscopy, leading to the observation of a short‐lived intermediate that proved to be reactive in both oxygen atom transfer and hydrogen abstraction reactions, while the peroxide efficiently transfers O atoms. Both for the enzyme and for the functional model, the key to O2 activation is proposed to represent a concomitant electron shift from the substrate/co‐ligand.

Synthesis and Characterization of a Highly Reactive and Robust Chlorine‐Bound Ni Single‐Atom‐Catalyst for the Continuous Flow Ring‐Opening Reaction of Epoxides

“…In addition, the application of the Ni SAC has focused far more on electrochemistry than on organic synthesis. Therefore, considering the potential activating properties of customized Cl‐functionalized Ni−SACs (Cl−Ni−SACs) such as the high Lewis acidity of Ni(II) [38] and Cl‐mediated hydrogen bonding, [39] their catalytic application in the epoxide ring opening reactions is worth investigating.…”

Generation and Reactivity of a NiIII2(μ-1,2-peroxo) Complex

“…Based on these data, and similar species previously reported, we tentatively propose that 1-Na is a dimer as depicted in Scheme 1. 46 Treatment of 1-Na in DCM with dry oxygen at room temperature results in an intractable brown mixture of diamagnetic products as ascertained by 1 H NMR spectroscopy. However, at −78 °C addition of dry oxygen to 1-Na in DCM results in a color change from emerald green to dark purple.…”