Actinide Organometallic Complexes with π‐Ligands

Abstract

The recent developments and results from the organometallic chemistry of the actinides are reviewed. In the last one and a half years structure data of about 15 organometallic complexes of trans-uranium actinides (Np or Pu) have been published, all involving π-ligands in the coordination sphere of the metal ion. On the basis of these data a comparison of these molecules is presented. Depending on the steric demands of the ligands, effects like the actinide contraction seem to be stronger or weaker in the structural features. This indicates that the interplay between the actinide ion and the π-ligand is rather flexible, enabling the formation of stable bonds over a broad range of actinide ion oxidation states.

f‐Block Phospholyl and Arsolyl Chemistry

“…Firstly, we speculate that the heteroatom lone pairs in phospholyl and arsolyl rings in η 5 ‐bound complexes could be actively involved in reactivity profiles. Ln and An Cp and Cp R complexes have well‐established applicability in a wide range of hydroelementation and polymerisation reactions, including catalytic processes, [75] and low oxidation state Ln and An complexes of these ligands have shown rich small molecule activation chemistry [2d–g] . We anticipate that future investigations with analogous Ln and An phospholyl and arsolyl complexes will furnish results that complement and contrast with established Cp/Cp R chemistry, with the possible involvement of P and As lone pairs in these reactions an exciting prospect.…”

“…For transuranic elements, the increasing radiological hazard across the An series limits investigations to specialist facilities, [1b] but the recent extension of Cp R chemistry to a structurally authenticated Am III complex [74] indicates that phospholyls and arsolyls can also find success for Np, Pu, Am and even beyond. Investigations into An phospholyl and arsolyl redox chemistry is also currently limited to U III and U IV examples, where there are a wide range of An oxidation states to explore; [1b] for example, for U, Cp R complexes have been structurally authenticated from the +2 to the +6 oxidation state [2d–g] …”

Synthesis and Utility of Neptunium(III) Hydrocarbyl Complex

“…These complexes are of interest for their small‐molecule activation, spectroscopic and magnetic properties, as well as starting materials for advancing the fundamental coordination chemistry and reactivity of low‐valent actinides . To date, the organometallic chemistry of the actinides, particularly transuranic chemistry, has been dominated by π‐ligands such as cyclopentadienyl and other derivatives …”

“…[17] To date, the organometallic chemistry of the actinides, particularly transuranic chemistry, has been dominated by π-ligands such as cyclopentadienyl and other derivatives. [18] The coordination chemistry of transuranic elements has lagged behind that of thorium and uranium due to lack of easily accessible starting materials as well as the associated cost and infrastructure required in obtaining and handling these elements. Since transuranic elements are byproducts of irradiating uranium, exploring the chemistry of these elements is necessary to better understand how to separate the minor actinides from complex matrices when recycling spent nuclear fuel.…”

Synthesis and reactivity of low-valent uranium and neptunium complexes

“…136 To date, the organometallic chemistry of the actinides, particularly transuranic chemistry, has been dominated by π-ligands such as cyclopentadienyl and other derivatives. 137 The coordination chemistry of transuranic elements has lagged behind that of thorium and uranium because of the lack of easily accessible starting materials, as well as the associated cost and infrastructure required to obtain and handle these elements. Since transuranic elements are byproducts of irradiating uranium with neutrons, exploring the chemistry of these elements is necessary to better understand how to separate the minor actinides from complex matrices when recycling spent nuclear fuel.…”