Activation of carbon suboxide (C3O2) by U(iii) to form a cyclobutane-1,3-dione ring

Abstract

The activation of C₃O₂ by the U(III) complex [U(η⁵-Cp′)₃] (Cp′ = C₅H₄SiMe₃) is described. The reaction results in the reductive coupling of three C₃O₂ units to form a tetranuclear complex with a central cyclobutane-1,3-dione ring, with concomitant loss of CO. Careful control of reaction conditions has allowed the trapping of an intermediate, a dimeric bridging ketene complex, which undergoes insertion of C₃O₂ to form the final product.