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Triamidoamine uranium(IV)–arsenic complexes containing one-, two- and threefold U–As bonding interactions

Nature Chemistry volume 7, pages 582–590 (2015)Cite this article

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Abstract

To further our fundamental understanding of the nature and extent of covalency in uranium–ligand bonding, and the benefits that this may have for the design of new ligands for nuclear waste separation, there is burgeoning interest in the nature of uranium complexes with soft- and multiple-bond-donor ligands. Despite this, there have so far been no examples of structurally authenticated molecular uranium–arsenic bonds under ambient conditions. Here, we report molecular uranium(IV)–arsenic complexes featuring formal single, double and triple U–As bonding interactions. Compound formulations are supported by a range of characterization techniques, and theoretical calculations suggest the presence of polarized covalent one-, two- and threefold bonding interactions between uranium and arsenic in parent arsenide [U–AsH2], terminal arsinidene [U=AsH] and arsenido [U≡AsK2] complexes, respectively. These studies inform our understanding of the bonding of actinides with soft donor ligands and may be of use in future ligand design in this area.

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Figure 1: Synthesis of compounds 2c, 3c, 4, 5, 6 and 7 from precursor 1.
Figure 2: Molecular structures of 2c, 3c and 4.
Figure 3: Variable-temperature effective magnetic moment data for 2c, 3c and 4.
Figure 4: Selected NBOs that principally represent the U–As σ2 and σ2π2 interactions in 2c and 3c.
Figure 5: Selected NBOs that principally represent the four U–As σ2π4 interactions in the pruned model of 4′.

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Acknowledgements

The authors acknowledge the Royal Society, the European Research Council, the Engineering and Physical Sciences Research Council, the Universities of Nottingham, Manchester and Regensburg, the Deutsche Forschungsgemeinschaft, the UK National Nuclear Laboratory, COST Action CM1006 and the EPSRC UK National EPR Facility for supporting this work.

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Authors and Affiliations

  1. School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK

    Benedict M. Gardner, Jonathan McMaster, William Lewis, Alexander J. Blake & Stephen T. Liddle

  2. Institut of Inorganic Chemistry, University of Regensburg, Universitaets Strasse 31, Regensburg, 93053, Germany

    Gábor Balázs & Manfred Scheer

  3. School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, UK

    Floriana Tuna & Eric J. L. McInnes

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  1. Benedict M. Gardner
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Contributions

B.M.G. synthesized and characterized the compounds. G.B. prepared the parent potassium arsenide complex. F.T. and E.J.L.M. recorded and interpreted the magnetic data. J.M. and S.T.L. conducted and analysed the theoretical calculations. W.L. and A.J.B. carried out the X-ray single-crystal diffraction work. S.T.L. and M.S. originated the central idea, supervised the work, analysed the data and wrote the manuscript with contributions from all co-authors.

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Correspondence to Manfred Scheer or Stephen T. Liddle.

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First set of crystallographic data for compound 2c (CIF 29 kb)

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Second set of crystallographic data for compound 2c (CIF 55 kb)

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Crystallographic data for compound 3c (CIF 84 kb)

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Crystallographic data for compound 4 (CIF 116 kb)

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Crystallographic data for compound 5 (CIF 112 kb)

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Crystallographic data for compound 7 (CIF 81 kb)

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Gardner, B., Balázs, G., Scheer, M. et al. Triamidoamine uranium(IV)–arsenic complexes containing one-, two- and threefold U–As bonding interactions. Nature Chem 7, 582–590 (2015). https://doi.org/10.1038/nchem.2279

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