Preparation and Characterization of Uranium–Iron Triple‐Bonded UFe(CO)₃⁻ and OUFe(CO)₃⁻ Complexes

Abstract

Abstract We report the preparation of UFe(CO) 3 − and OUFe(CO) 3 − complexes using a laser‐vaporization supersonic ion source in the gas phase. These compounds were mass‐selected and characterized by infrared photodissociation spectroscopy and state‐of‐the‐art quantum chemical studies. There are unprecedented triple bonds between U 6d/5f and Fe 3d orbitals, featuring one covalent σ bond and two Fe‐to‐U dative π bonds in both complexes. The uranium and iron elements are found to exist in unique formal U(I or III) and Fe(−II) oxidation states, respectively. These findings suggest that there may exist a whole family of stable df–d multiple‐bonded f‐element‐transition‐metal compounds that have not been fully recognized to date.