Electronic Structure\nand CO<sub>2</sub> Reactivity\nof Group IV/V/VI Tetraperoxometalates

Tetraperoxo metal complexes are a category of dioxygen\ncompounds\nwith novel properties. One of their underconsidered applications is\nin direct air capture (DAC) reactions, whose study is of great interest\nin order to slow the effects of climate change. Through computational\nmodeling, the present work considers a family of tetraperoxometalate\ncomplexes of the form [M(O<sub>2</sub>)<sub>4</sub>]<sup><i>x</i>−</sup> that capture atmospheric CO<sub>2</sub> to produce\n[MO(O<sub>2</sub>)<sub>2</sub>(CO<sub>3</sub>)]<sup><i>x</i>−</sup> and O<sub>2</sub>. This reaction was experimentally\ndocumented with vanadium and serves as a model for analogous reactions\nwith Group IV (<i>x</i> = 4; M = Ti, Zr, Hf), Group V (<i>x</i> = 3; M = V, Nb, Ta), and Group VI (<i>x</i> =\n2; M = Cr, Mo, W) metal centers. Descriptors from density functional\ntheory (DFT) calculations, including optimized structures, partial\ncharges, and frontier orbital interactions, provide rationalization\nfor predicted differences in reactivity. Of the nine complexes studied,\n[Ti(O<sub>2</sub>)<sub>4</sub>]<sup>4–</sup> and [W(O<sub>2</sub>)<sub>4</sub>]<sup>2–</sup>, respectively, represent the most\nand least efficient DAC reagents from their differing abilities to\nstabilize a bidentate peroxycarbonate (κ<sup>2</sup>–CO<sub>4</sub><sup>2–</sup>) intermediate in the proposed reaction\nmechanism.