Focus

Actinide chemistry

Our understanding of the bonding, reactivity and electronic structure of actinides, though it has both fundamental and practical importance, lags behind that of the rest of the periodic table. A collection of articles in this Focus highlights recent developments in this area, in particular featuring uranium(VI) dianions bearing four U–N multiple bonds, berkelium(IV) stabilized in aqueous solution and a plutonium material showing evidence for the delocalization of 5f electrons.

Content

  • Nature Chemistry | Article

    The field of high-valent uranium chemistry has been dominated by the linear uranyl moiety [UO2]2+ and its imido analogues. A family of tetrakis(imido)uranate dianions has now been developed that displays four uranium–nitrogen multiple bonds. Their geometry is dictated by cation coordination and steric factors rather than electronic ones.

    • Nickolas H. Anderson
    • , Jing Xie
    • , Debmalya Ray
    • , Matthias Zeller
    • , Laura Gagliardi
    •  &  Suzanne C. Bart
  • Nature Chemistry | Article

    Berkelium is the only transplutonium element predicted to be able to exhibit both +III and +IV oxidation states in solution. Bk(IV) has now been stabilized through chelation with a siderophore derivative. The resulting neutral coordination compound was characterized and compared with the negatively charged species obtained by chelation of neighbouring trivalent actinides.

    • Gauthier J.-P. Deblonde
    • , Manuel Sturzbecher-Hoehne
    • , Peter B. Rupert
    • , Dahlia D. An
    • , Marie-Claire Illy
    • , Corie Y. Ralston
    • , Jiri Brabec
    • , Wibe A. de Jong
    • , Roland K. Strong
    •  &  Rebecca J. Abergel
  • Nature Chemistry | Article

    Unlike in the d block, intervalence charge transfer is rare in the 5f block owing to localized valence electrons and poor overlap between metal and ligand orbitals. Delocalization of 5f electrons has now been observed in a Pu(III)/Pu(IV)–pyridinedicarboxylate solid-state compound. It occurs through metal-to-ligand charge transfer with both plutonium centres.

    • Samantha K. Cary
    • , Shane S. Galley
    • , Matthew L. Marsh
    • , David L. Hobart
    • , Ryan E. Baumbach
    • , Justin N. Cross
    • , Jared T. Stritzinger
    • , Matthew J. Polinski
    • , Laurent Maron
    •  &  Thomas E. Albrecht-Schmitt

From the archives

  • Nature Chemistry | Article

    Covalency in actinide–­ligand bonding is poorly understood compared to that in other parts of the periodic table due to the lack of experimental data. Here, pulsed electron paramagnetic resonance methods are used to directly measure the electron spin densities at coordinated ligands in molecular thorium and uranium complexes.

    • Alasdair Formanuik
    • , Ana-Maria Ariciu
    • , Fabrizio Ortu
    • , Reece Beekmeyer
    • , Andrew Kerridge
    • , Floriana Tuna
    • , Eric J. L. McInnes
    •  &  David P. Mills
  • Nature Chemistry | Article

    Probing the chemistry of transuranic elements is notoriously challenging. Now, three neptunium(III) organometallic sandwich complexes have been prepared using a flexible macrocycle as ligand, and their molecular and electronic structures characterized, adding to our understanding of the behaviour of f-elements and suggesting that the lower oxidation state Np(II) may be chemically accessible.

    • Michał S. Dutkiewicz
    • , Joy H. Farnaby
    • , Christos Apostolidis
    • , Eric Colineau
    • , Olaf Walter
    • , Nicola Magnani
    • , Michael G. Gardiner
    • , Jason B. Love
    • , Nikolas Kaltsoyannis
    • , Roberto Caciuffo
    •  &  Polly L. Arnold
  • Nature Chemistry | Article

    The nature of actinide–ligand bonding is attracting attention, in particular in the context of nuclear waste separations. Structurally authenticated one-, two- and threefold uranium–arsenic bonding interactions are now reported. Computational analysis suggests the presence of polarized σ2, σ2π2, and σ2π4 in the arsenide, terminal arsinidene, and arsenido complexes, respectively.

    • Benedict M. Gardner
    • , Gábor Balázs
    • , Manfred Scheer
    • , Floriana Tuna
    • , Eric J. L. McInnes
    • , Jonathan McMaster
    • , William Lewis
    • , Alexander J. Blake
    •  &  Stephen T. Liddle
  • Nature Chemistry | Article

    Multi-electron redox chemistry is important in transition-metal-mediated processes, but is rarely observed with uranium due to its propensity to undergo single-electron reactions. Now, uranium can use its electrons, coupled with those stored in redox-active ligands, to perform multi electron reduction of organoazides and form uranium tris(imido) derivatives.

    • Nickolas H. Anderson
    • , Samuel O. Odoh
    • , Yiyi Yao
    • , Ursula J. Williams
    • , Brian A. Schaefer
    • , John J. Kiernicki
    • , Andrew J. Lewis
    • , Mitchell D. Goshert
    • , Phillip E. Fanwick
    • , Eric J. Schelter
    • , Justin R. Walensky
    • , Laura Gagliardi
    •  &  Suzanne C. Bart