Ni-based oxide materials are promising candidates for catalyzing
the oxygen evolution reaction. The detailed mechanism of water splitting in
these systems has been of interest with a goal of understanding the
intermediate species vital for catalytic activity. A potential intermediate
species prior to release of oxygen is a bridging Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo)
complex. However, Ni<sub>2</sub>(<i>μ</i>-1,2-peroxo) complexes are rare in
general and are unknown with oxidation states higher than Ni<sup>II</sup>.
Herein, we report the isolation of such an unusual high-valent species in a Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo)
complex, which has been characterized using single-crystal X-ray diffraction
and X-ray absorption, NMR, and UV-vis spectroscopies. In addition, treatment
with excess tetrabutylammonium chloride results in regeneration of the
precursor Ni–Cl
species, implicating the reversible release of oxygen or a
reactive oxygen species. Taken together, this suggests that Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo)
species are accessible and may be viable intermediates during the oxygen
evolution reaction.
Generation and Reactivity of a NiIII2(μ-1,2-peroxo) Complex
