DFT Study of Halide‐Free Mechanism of the CO2 Cycloaddition onto Epoxide by [PW11O39{Zn(H2O)}]5−: Evidences for the Formation of Hydrogencarbonate Intermediates

The computational study, sustained by experimental data, of the catalytic activity of [PW₁₁O₃₉{Zn(H₂O)}]⁵⁻ in CO₂ cycloaddition to epoxide highlights how the carbonic anhydrase-like character of this complex couples to the versatile binding properties of the polyoxometalate in this reaction pathway.

Abstract

The intertwined experimental and theoretical study of the reaction of CO₂ with styrene oxide in the presence of the tetraoctylammonium salt of [PW₁₁O₃₉Zn^II(H₂O)]⁵⁻ evidences the carbonic anhydrase-like role of the polyoxometalate center in catalyzing the reaction. We computationally propose a reaction pathway involving the transient formation of an HCO₃ ⁻ moiety involved in the stepwise conversion of the epoxide into a cyclic carbonate. These calculations enabled us to improve the catalytic reactivity of these polyoxometalates by introducing HCO₃ ⁻ as a co-catalyst in the cycloaddition reactions of CO₂ on a variety of epoxides.

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