Mechanistic Studies on the Reductive Cyclooligomerisation of CO by U (III) Mixed Sandwich Complexes; the Molecular Structure of (U (η-C8H6SiiPr3-1, 42) (η-Cp*) 2 (μ-η1: η1-C2O2)

The stoichiometric reaction of 1 equiv of CO with (U (eta-C8H6SiiPr3-1, 42) (eta-Cp*) affords the linear diuranium ynediolate complex (U (eta-C8H6SiiPr3-1, 42) (eta-Cp*) 2 (mu-eta1: eta1-C2O2) which does not react with further CO to give the deltate derivative (U (eta-C8H6SiiPr3-1, 42) (eta-Cp*) 2 (mu-eta1: eta2-C3O3). Spectroscopic and computational studies suggest a plausible mechanism for the formation of the deltate complex, in which a "zig-zag" diuranium ynediolate species is the key intermediate.