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The role of uranium–arene bonding in H2O reduction catalysis

Abstract

The reactivity of uranium compounds towards small molecules typically occurs through stoichiometric rather than catalytic processes. Examples of uranium catalysts reacting with water are particularly scarce, because stable uranyl groups form that preclude the recovery of the uranium compound. Recently, however, an arene-anchored, electron-rich uranium complex has been shown to facilitate the electrocatalytic formation of H2 from H2O. Here, we present the precise role of uranium–arene δ bonding in intermediates of the catalytic cycle, as well as details of the atypical two-electron oxidative addition of H2O to the trivalent uranium catalyst. Both aspects were explored by synthesizing mid- and high-valent uranium–oxo intermediates and by performing comparative studies with a structurally related complex that cannot engage in δ bonding. The redox activity of the arene anchor and a covalent δ-bonding interaction with the uranium ion during H2 formation were supported by density functional theory analysis. Detailed insight into this catalytic system may inspire the design of ligands for new uranium catalysts.

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Figure 1: Overview of the proposed mechanism for electrocatalytic H2O reduction with 1, graphical representations of mes complex 1 and tacn analogue 3, and the synthetic scheme towards oxo complexes relevant for the catalytic cycle.
Figure 2: Molecular structures of oxo complexes 2, 2–K and 4 determined by single-crystal X-ray crystallography, and a model of the distorted mesitylene backbone of complex 2.
Figure 3: EPR spectroscopic analysis of U(V) oxo complexes 2 and 4.
Figure 4: Electronic structure analysis by SQUID magnetometry and electronic absorption spectroscopy.
Figure 5: Calculated molecular orbital maps describing the electronic structure of complex 2.
Figure 6: Calculated reaction profile and SOMOs of the first transition state for H2O reduction with complex 1.

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References

  1. Liddle, S. T. The renaissance of non-aqueous uranium chemistry. Angew. Chem. Int. Ed. 54, 8604–8641 (2015).

    CAS  Google Scholar 

  2. Lukens, W. L., Beshouri Sharon, M. Jr, Blosch, L. L. & Andersen, R. A. Oxidative elimination of H2 from [CP′2U(µ-OH)]2 to form [Cp′2U(µO)]2 where Cp′ is 1,3-(Me3C)2C5H3 or 1,3-(Me3Si)2C5H3 . J. Am. Chem. Soc. 118, 901–902 (1996).

    CAS  Google Scholar 

  3. Schmidt, A.-C., Heinemann, F. W., Lukens, W. W. & Meyer, K. Molecular and electronic structure of dinuclear uranium bis-μ-oxo complexes with diamond core structural motifs. J. Am. Chem. Soc. 136, 11980–11993 (2014).

    CAS  PubMed  Google Scholar 

  4. Summerscales, O. T., Cloke, F. G. N., Hitchcock, P. B., Green, J. C. & Hazari, N. Reductive cyclotrimerization of carbon monoxide to the deltate dianion by an organometallic uranium complex. Science 311, 829–831 (2006).

    CAS  PubMed  Google Scholar 

  5. Schmidt, A.-C., Nizovtsev, A. V., Scheurer, A., Heinemann, F. W. & Meyer, K. Uranium-mediated reductive conversion of CO2 to CO and carbonate in a single-vessel, closed synthetic cycle. Chem. Commun. 48, 8634–8636 (2012).

    CAS  Google Scholar 

  6. Halter, D. P., Heinemann, F. W., Bachmann, J. & Meyer, K. Uranium-mediated electrocatalytic dihydrogen production from water. Nature 530, 317–321 (2016).

    CAS  PubMed  Google Scholar 

  7. Fox, A. R., Bart, S. C., Meyer, K. & Cummins, C. C. Towards uranium catalysts. Nature 455, 341–349 (2008).

    CAS  PubMed  Google Scholar 

  8. La Pierre, H. S. & Meyer, K. Activation of small molecules by molecular uranium complexes. Prog. Inorg. Chem. 58, 303–416 (2014).

    CAS  Google Scholar 

  9. Castro-Rodriguez, I., Nakai, H., Zakharov, L. N., Rheingold, A. L. & Meyer, K. A linear, O-coordinated η1-CO2 bound to uranium. Science 305, 1757–1759 (2004).

    CAS  PubMed  Google Scholar 

  10. Lam, O. P., Bart, S. C., Kameo, H., Heinemann, F. W. & Meyer, K. Insights into the mechanism of carbonate formation through reductive cleavage of carbon dioxide with low-valent uranium centers. Chem. Commun. 46, 3137–3139 (2010).

    CAS  Google Scholar 

  11. Lam, O. P. & Meyer, K. Uranium-mediated carbon dioxide activation and functionalization. Polyhedron 32, 1–9 (2012).

    CAS  Google Scholar 

  12. Schmidt, A.-C. et al. Activation of SO2 and CO2 by trivalent uranium leading to sulfite/dithionite and carbonate/oxalate complexes. Chem. Eur. J. 20, 13501–13506 (2014).

    CAS  PubMed  Google Scholar 

  13. Gardner, B. M. et al. Homologation and functionalization of carbon monoxide by a recyclable uranium complex. Proc. Natl Acad. Sci. USA 109, 9265–9270 (2012).

    CAS  PubMed  Google Scholar 

  14. Fortier, S., Brown, J. L., Kaltsoyannis, N., Wu, G. & Hayton, T. W. Synthesis, molecular and electronic structure of UV(O)[N(SiMe3)2]3 . Inorg. Chem. 51, 1625–1633 (2012).

    CAS  PubMed  Google Scholar 

  15. Shannon, R. D. Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr. A 32, 751–767 (1976).

    Google Scholar 

  16. Diaconescu, P. L., Arnold, P. L., Baker, T. A., Mindiola, D. J. & Cummins, C. C. Arene-bridged diuranium complexes: inverted sandwiches supported by δ backbonding. J. Am. Chem. Soc. 122, 6108–6109 (2000).

    CAS  Google Scholar 

  17. Evans, W. J., Kozimor, S. A., Ziller, J. W. & Kaltsoyannis, N. Structure, reactivity, and density functional theory analysis of the six-electron reductant, [(C5Me5)2U]2(μ-η66-C6H6), synthesized via a new mode of (C5Me5)3M reactivity. J. Am. Chem. Soc. 126, 14533–14547 (2004).

    CAS  PubMed  Google Scholar 

  18. Patel, D. et al. A formal high oxidation state inverse-sandwich diuranium complex a new route to f-block-metal bonds. Angew. Chem. Int. Ed. 50, 10388–10392 (2011).

    CAS  Google Scholar 

  19. Camp, C., Mougel, V., Pécaut, J., Maron, L. & Mazzanti, M. Cation-mediated conversion of the state of charge in uranium arene inverted-sandwich complexes. Chem. Eur. J. 19, 17528–17540 (2013).

    CAS  PubMed  Google Scholar 

  20. Liddle, S. T. Inverted sandwich arene complexes of uranium. Coord. Chem. Rev. 293–294, 211–227 (2015).

    Google Scholar 

  21. Bart, S. C., Heinemann, F. W., Anthon, C., Hauser, C. & Meyer, K. A new tripodal ligand system with steric and electronic modularity for uranium coordination chemistry. Inorg. Chem. 48, 9419–9426 (2009).

    CAS  PubMed  Google Scholar 

  22. La Pierre, H. S., Kameo, H., Halter, D. P., Heinemann, F. W. & Meyer, K. Coordination and redox isomerization in the reduction of a uranium(III) monoarene complex. Angew. Chem. Int. Ed. 53, 7154–7157 (2014).

    CAS  Google Scholar 

  23. Halter, D. P., La Pierre, H. S., Heinemann, F. W. & Meyer, K. Uranium(IV) halide (F, Cl, Br, and I) monoarene complexes. Inorg. Chem. 53, 8418–8424 (2014).

    CAS  PubMed  Google Scholar 

  24. La Pierre, H. S., Scheurer, A., Heinemann, F. W., Hieringer, W. & Meyer, K. Synthesis and characterization of a uranium(II) monoarene complex supported by δ backbonding. Angew. Chem. Int. Ed. 53, 7158–7162 (2014).

    CAS  Google Scholar 

  25. Franke, S. M. et al. Uranium(III) complexes with bulky aryloxide ligands featuring metal–arene interactions and their reactivity toward nitrous oxide. Inorg. Chem. 52, 10552–10558 (2013).

    CAS  PubMed  Google Scholar 

  26. Arney, D. S. J. & Burns, C. J. Synthesis and structure of high-valent organouranium complexes containing terminal monooxo functional groups. J. Am. Chem. Soc. 115, 9840–9841 (1993).

    CAS  Google Scholar 

  27. King, D. M. et al. Single-molecule magnetism in a single-ion triamidoamine uranium(V) terminal mono-oxo complex. Angew. Chem. Int. Ed. 52, 4921–4924 (2013).

    CAS  Google Scholar 

  28. Bart, S. C. et al. Carbon dioxide activation with sterically pressured mid- and high-valent uranium complexes. J. Am. Chem. Soc. 130, 12536–12546 (2008).

    CAS  PubMed  Google Scholar 

  29. Batsanov, S. S. Van der Waals radii of elements. Inorg. Mater. 37, 871–885 (2001).

    CAS  Google Scholar 

  30. Effenberger, F. 1,3,5-tris(dialkylamino)benzenes: model compounds for the electrophilic substitution and oxidation of aromatic compounds. Acc. Chem. Res. 22, 27–35 (1989).

    CAS  Google Scholar 

  31. Anamimoghadam, O. et al. Electronically stabilized nonplanar phenalenyl radical and its planar isomer. J. Am. Chem. Soc. 137, 14944–14951 (2015).

    CAS  PubMed  Google Scholar 

  32. Kochi, J. K., Rathore, R. & Le Maguères, P. Stable dimeric aromatic cation−radicals. Structural and spectral characterization of through-space charge delocalization. J. Org. Chem. 65, 6826–6836 (2000).

    CAS  PubMed  Google Scholar 

  33. Neidig, M. L., Clark, D. L. & Martin, R. L. Covalency in f-element complexes. Coord. Chem. Rev. 257, 394–406 (2013).

    CAS  Google Scholar 

  34. Zi, G. et al. Preparation and reactions of base-free bis(1,2,4-tri-tert-butylcyclopentadienyl)uranium oxide, Cp′2UO. Organometallics 24, 4251–4264 (2005).

    CAS  Google Scholar 

  35. Kraft, S. J., Walensky, J., Fanwick, P. E., Hall, M. B. & Bart, S. C. Crystallographic evidence of a base-free uranium(IV) terminal oxo species. Inorg. Chem. 49, 7620–7622 (2010).

    CAS  PubMed  Google Scholar 

  36. Evans, W. J., Kozimor, S. A. & Ziller, J. W. Bis(pentamethylcyclopentadienyl) U(III) oxide and U(IV) oxide carbene complexes. Polyhedron 23, 2689–2694 (2004).

    CAS  Google Scholar 

  37. Brown, J. L., Fortier, S., Lewis, R. A., Wu, G. & Hayton, T. W. A complete family of terminal uranium chalcogenides, [U(E)(N{SiMe3}2)3] (E = O, S, Se, Te). J. Am. Chem. Soc. 134, 15468–15475 (2012).

    CAS  PubMed  Google Scholar 

  38. Gourier, D., Caurant, D., Berthet, J. C., Boisson, C. & Ephritikhine, M. Influence of the nature of the ligands on the electronic ground state of organouranium(V) compounds, studied by electron paramagnetic resonance. Inorg. Chem. 36, 5931–5936 (1997).

    CAS  PubMed  Google Scholar 

  39. Pankhurst, J. R. et al. Inner-sphere vs. outer-sphere reduction of uranyl supported by a redox-active, donor-expanded dipyrrin. Chem. Sci. 8, 108–116 (2017).

    CAS  PubMed  Google Scholar 

  40. Kindra, D. R. & Evans, W. J. Magnetic susceptibility of uranium complexes. Chem. Rev. 114, 8865–8882 (2014).

    CAS  PubMed  Google Scholar 

  41. Kosog, B., Kefalidis, C. E., Heinemann, F. W., Maron, L. & Meyer, K. Uranium(III)-mediated C–C-coupling of terminal alkynes: formation of dinuclear uranium(IV) vinyl complexes. J. Am. Chem. Soc. 134, 12792–12797 (2012).

    CAS  PubMed  Google Scholar 

  42. Lam, O. P., Heinemann, F. W. & Meyer, K. A new diamantane functionalized tris(aryloxide) ligand system for small molecule activation chemistry at reactive uranium complexes. C. R. Chim. 13, 803–811 (2010).

    CAS  Google Scholar 

  43. Graves, C. R. et al. Probing the chemistry, electronic structure and redox energetics in organometallic pentavalent uranium complexes. Inorg. Chem. 47, 11879–11891 (2008).

    CAS  PubMed  Google Scholar 

  44. Tsoureas, N., Kilpatrick, A. F. R., Inman, C. J. & Cloke, F. G. N. Steric control of redox events in organo-uranium chemistry: synthesis and characterisation of U(v) oxo and nitrido complexes. Chem. Sci. 7, 4624–4632 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  45. Rosenzweig, M. W. et al. Uranium(IV) terminal hydrosulfido and sulfido complexes insights into the nature of the uranium–sulfur bond. Chem. Sci. 7, 5857–5866 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  46. Anderson, N. H. et al. Harnessing redox activity for the formation of uranium tris(imido) compounds. Nat. Chem. 6, 919–926 (2014).

    CAS  PubMed  Google Scholar 

  47. Mohammad, A., Cladis, D. P., Forrest, W. P., Fanwick, P. E. & Bart, S. C. Reductive heterocoupling mediated by Cp*2U(2,2′-bpy). Chem. Commun. 48, 1671–1673 (2012).

    CAS  Google Scholar 

  48. Kraft, S. J. et al. Synthesis, characterization, and multielectron reduction chemistry of uranium supported by redox-active α-diimine ligands. Inorg. Chem. 50, 9838–9848 (2011).

    CAS  PubMed  Google Scholar 

  49. Lu, E. & Liddle, S. T. Uranium-mediated oxidative addition and reductive elimination. Dalton Trans. 44, 12924–12941 (2015).

    CAS  PubMed  Google Scholar 

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Acknowledgements

The authors thank H.S. La Pierre for discussions and M.E. Miehlich for assistance with EPR spectroscopy. D.P.H. acknowledges support from the Graduate School of Molecular Science (GSMS) of FAU Erlangen-Nürnberg. The Bundesministerium für Bildung und Forschung (BMBF, support codes 02NUK012C and 02NUK020C), the FAU Erlangen-Nürnberg and COST Action CM1006 are acknowledged for funding.

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D.P.H. and K.M. planned the research and prepared the manuscript. D.P.H. performed the experiments. F.W.H. conducted the XRD analyses and refined structures. L.M. performed theoretical calculations and analyses. All authors edited and reviewed the manuscript in the context of their contributions. K.M. supervised all aspects of the project.

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Correspondence to Karsten Meyer.

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The authors declare no competing financial interests.

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Crystallographic data for compound 2-K (CIF 1526 kb)

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Crystallographic data for compound 2 (CIF 8189 kb)

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Crystallographic data for compound 3 (CIF 3005 kb)

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Crystallographic data for compound 4 (CIF 7920 kb)

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Halter, D., Heinemann, F., Maron, L. et al. The role of uranium–arene bonding in H2O reduction catalysis. Nature Chem 10, 259–267 (2018). https://doi.org/10.1038/nchem.2899

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