Solid-state auride salts featuring the negatively charged Au ion are known to be stable in the presence of alkali metal counterions. While such electron-rich species might be expected to be nucleophilic (in the same manner as I, for example), their instability in solution means that this has not been verified experimentally. Here we report a two-coordinate gold complex (NON)AlAuPtBu3 (where NON is the chelating tridentate ligand 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene) that features a strongly polarized bond, Auδ–Alδ+. This is synthesized by reaction of the potassium aluminyl compound [K{Al(NON)}]2 with tBu3PAuI. Computational studies of the complex, including quantum theory of atoms in molecules charge analysis, imply a charge at gold (−0.82) that is in line with the relative electronegativities of the two metals (Au: 2.54; Al: 1.61 on the Pauling scale). Consistently, the complex is found to act as a nucleophilic source of gold, reacting with diisopropylcarbodiimide and CO2 to give the Au–C bonded insertion products (NON)Al(X2C)AuPtBu3 (X = NiPr, 4; X = O, 5).

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Data availability

Crystallographic data for the structures reported in this Article have been deposited at the Cambridge Crystallographic Data Centre under deposition nos. CCDC 1854973 (2), 1854972 (3), 1854971 (4) and 1854974 (5). Copies of the data can be obtained free of charge from www.ccdc.cam.ac.uk/structures/. All other data supporting the findings of this study are available within the Article and its Supplementary Information, at the Oxford University Research Archive (https://ora.ox.ac.uk) and from the corresponding authors upon reasonable request.

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This work was supported by the SCG Oxford Centre of Excellence. P.V. thanks the Magnus Ehrnrooth, Finnish Cultural and Emil Aaltonen Foundations for postdoctoral funding. Computational resources were provided by CSC – IT Center for Science, Finland, the Finnish Grid and Cloud Infrastructure (persistent identifier nrn:nbn:fi:research-infras-2016072533) and the University of Jyväskylä.

Author information


  1. Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK

    • Jamie Hicks
    • , Petra Vasko
    • , Jose M. Goicoechea
    •  & Simon Aldridge
  2. Department of Chemistry, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland

    • Akseli Mansikkamäki
    •  & Petra Vasko


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J.H. carried out the synthetic and reaction studies. A.M. and P.V. carried out the computational analyses. J.H. conducted the crystallographic studies. J.H., J.M.G. and S.A. wrote the manuscript. J.M.G. and S.A. managed the project.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to Jose M. Goicoechea or Simon Aldridge.

Supplementary information

  1. Supplementary Information

    General considerations and starting material preparations; synthetic, spectroscopic and analytical data; 1H-NMR spectra; X-ray crystallographic studies; computational studies

  2. Crystallographic data

    CIF for compound 2; CCDC reference: 1854973

  3. Crystallographic data

    CIF for compound 3; CCDC reference: 1854972

  4. Crystallographic data

    CIF for compound 4; CCDC reference: 1854971

  5. Crystallographic data

    CIF for compound 5; CCDC reference: 1854974

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