Activation Of Carbon Suboxide (C3o2) By U(Iii) To Form A Cyclobutane-1,3-Dione Ring

The activation of C3O2 by the U(iii) complex [U((5)-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.