Mechanistic Studies on the Reductive Cyclooligomerisation of CO by U(III) Mixed Sandwich Complexes; the Molecular Structure of [(U(η-C8H6{SiiPr3-1,4}2)(η-Cp*)]2(μ-η11-C2O2)

Abstract
The stoichiometric reaction of 1 equiv of CO with [(U(η-C8H6{SiiPr3-1,4}2)(η-Cp*)] affords the linear diuranium ynediolate complex [(U(η-C8H6{SiiPr3-1,4}2)(η-Cp*)]2(μ-η11-C2O2) which does not react with further CO to give the deltate derivative [(U(η-C8H6{SiiPr3-1,4}2)(η-Cp*)]2(μ-η12-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.