Reductive disproportionation of carbon dioxide to carbonate and squarate products using a mixed-sandwich U(iii) complex

Abstract

The mixed-sandwich U(III) complexes [U(η-C₈H₆{SiⁱPr₃-1,4}₂)(η-Cp^R)(THF)] (R = Me₅, Me₄H) react with CO₂ to give free CO and the U(IV) carbonate products [U(η-C₈H₆{SiⁱPr₃-1,4}₂)(η-Cp^R)]₂(μ-η¹:η²-CO₃)]; the latter has been structurally characterised for R = Me₄H; a 25% molar excess of the U(III) reductant gives a mixture of the carbonate and squarate [U(η-C₈H₆{SiⁱPr₃-1,4}₂)(η-C₅Me₄H)]₂(μ-η²:η²-C₄O₄) products—the first synthesis of an oxocarbon from a CO₂ carbon source.