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Uranium azide photolysis results in C–H bond activation and provides evidence for a terminal uranium nitride

Abstract

Uranium nitride [U≡N]x is an alternative nuclear fuel that has great potential in the expanding future of nuclear power; however, very little is known about the U≡N functionality. We show, for the first time, that a terminal uranium nitride complex can be generated by photolysis of an azide (U–N=N=N) precursor. The transient U≡N fragment is reactive and undergoes insertion into a ligand C–H bond to generate new N–H and N–C bonds. The mechanism of this unprecedented reaction has been evaluated through computational and spectroscopic studies, which reveal that the photochemical azide activation pathway can be shut down through coordination of the terminal azide ligand to the Lewis acid B(C6F5)3. These studies demonstrate that photochemistry can be a powerful tool for inducing redox transformations for organometallic actinide complexes, and that the terminal uranium nitride fragment is reactive, cleaving strong C–H bonds.

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Figure 1: Generation of UIV azide complexes.
Figure 2: Photochemical generation and reactivity of terminal uranium nitride.
Figure 3: UV–visible–NIR absorption spectra in a toluene solution.
Figure 4: DFT calculations on the mechanism for the formation of 5 from 3.
Figure 5: Deconvoluted UV–vis spectrum of (C5Me5)2U[N(SiMe3)2](N3) (3) and calculated (TD-DFT) electronic transitions (vertical red lines).
Figure 6: Analogy between cytochrome P450 and uranium nitride C−H activation.

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References

  1. Yeamans, C. B. et al. Oxidative ammonolysis of uranium(IV) fluorides to uranium(VI) nitride. J. Nucl. Mater. 374, 75–78 (2008).

    Article  CAS  Google Scholar 

  2. Streit, M. & Ingold, F. Nitrides as a nuclear fuel option. J. Eur. Ceram. Soc. 25, 2687–2692 (2005).

    Article  CAS  Google Scholar 

  3. Denning, R. G. Electronic structure and bonding in actinyl ions and their analogs. J. Phys. Chem. A 111, 4125–4143 (2007).

    Article  CAS  Google Scholar 

  4. Arnold, P. L. et al. Reduction and selective oxo group silylation of the uranyl dication. Nature 451, 315–317 (2008).

    Article  CAS  Google Scholar 

  5. Burdet, F., Pecaut, J. & Mazzanti, M. Isolation of a tetrameric cation–cation complex of pentavalent uranyl. J. Am. Chem. Soc. 128, 16512–16513 (2006).

    Article  CAS  Google Scholar 

  6. Steele, H. & Taylor, R. J. A theoretical study of the inner-sphere disproportionation reaction mechanism of the pentavalent actinyl ions. Inorg. Chem. 46, 6311–6318 (2007).

    Article  CAS  Google Scholar 

  7. Korobkov, I., Gambarotta, S. & Yap, G. P. A. A highly reactive uranium complex supported by the calix[4]tetrapyrrole tetraanion affording dinitrogen cleavage, solvent deoxygenation, and polysilanol depolymerization. Angew. Chem. Int. Ed. 41, 3433–3436 (2002).

    Article  CAS  Google Scholar 

  8. Evans, W. J., Kozimor, S. A. & Ziller, J. W. Molecular octa-uranium rings with alternating nitride and azide bridges. Science 309, 1835–1838 (2005).

    Article  CAS  Google Scholar 

  9. Evans, W. J. et al. Analysis of uranium azide and nitride complexes by atmospheric pressure chemical ionization mass spectrometry. Inorg. Chem. 46, 8008–8018 (2007).

    Article  CAS  Google Scholar 

  10. Fox, A. R. & Cummins, C. C. Uranium–nitrogen multiple bonding: the case of a four-coordinate uranium(VI) nitridoborate complex. J. Am. Chem. Soc. 131, 5716–5717 (2009).

    Article  CAS  Google Scholar 

  11. Fox, A. R., Arnold, P. L. & Cummins, C. C. Uranium–nitrogen multiple bonding: isostructural anionic, neutral and cationic uranium nitride complexes featuring a linear U=N=U core. J. Am. Chem. Soc. 132, 3250–3251 (2010).

    Article  CAS  Google Scholar 

  12. Nocton, G., Pecaut, J. & Mazzanti, M. A nitrido-centered uranium azido cluster obtained from a uranium azide. Angew. Chem. Int. Ed. 47, 3040–3042 (2008).

    Article  CAS  Google Scholar 

  13. Berry, J. F. et al. An octahedral coordination complex of iron(VI). Science 312, 1937–1941 (2006).

  14. Vogel, C. et al. An iron nitride complex. Angew. Chem. Int. Ed. 47, 2681–2684 (2008).

    Article  CAS  Google Scholar 

  15. Scepaniak, J. J. et al. Structural and spectroscopic characterization of an electrophilic iron nitrido complex. J. Am. Chem. Soc. 130, 10515–10517 (2008).

    Article  CAS  Google Scholar 

  16. Scepaniak, J. J. et al. Formation of ammonia from an iron nitrido complex. Angew. Chem. Int. Ed. 48, 3158–3160 (2009).

    Article  CAS  Google Scholar 

  17. Kalina, D. G., Marks, T. J. & Wachter, W. A. Photochemical synthesis of low-valent organothorium complexes. Evidence for photoinduced β-hydride elimination. J. Am. Chem. Soc. 99, 3877–3879 (1977).

    Article  CAS  Google Scholar 

  18. Bruno, J. W. et al. Mechanistic study of photoinduced β-hydride elimination. The facile photochemical synthesis of low-valent thorium and uranium organometallics. J. Am. Chem. Soc. 104, 1860–1869 (1982).

    Article  CAS  Google Scholar 

  19. Shaik, S. et al. Theoretical perspective on the structure and mechanism of cytochrome P450 enzymes. Chem. Rev. 105, 2279–2328 (2005).

    Article  CAS  Google Scholar 

  20. Thomson, R. K. et al. Noble reactions for the actinides: safe gold-based access to organouranium and azido complexes. Eur. J. Inorg. Chem. 1451–1455 (2009).

  21. Dori, Z. & Ziolo, R. F. Chemistry of coordinated azides. Chem. Rev. 73, 247–254 (1973).

    Article  CAS  Google Scholar 

  22. Rozsnyai, L. F. & Wrighton, M. S. Selective electrochemical deposition of polyaniline via photopatterning of a monolayer-modified substrate. J. Am. Chem. Soc. 116, 5993–5994 (1994).

    Article  CAS  Google Scholar 

  23. Arney, D. S. J. & Burns, C. J. Synthesis and properties of high-valent organouranium complexes containing terminal organoimido and oxo functional groups. A new class of organo-f-element complexes. J. Am. Chem. Soc. 117, 9448–9460 (1995).

    Article  CAS  Google Scholar 

  24. Peters, R. G., Warner, B. P. & Burns, C. J. The catalytic reduction of azides and hydrazines using high-valent organouranium complexes. J. Am. Chem. Soc. 121, 5585–5586 (1999).

    Article  CAS  Google Scholar 

  25. Peters, R. G. et al. C–H bond activation with actinides: the first example of intramolecular ring bite of a pentamethylcyclopentadienyl methyl group. Organometallics 18, 2587–2589 (1999).

    Article  CAS  Google Scholar 

  26. 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).

    Article  CAS  Google Scholar 

  27. Monreal, M. J. & Diaconescu, P. L. A weak interaction between iron and uranium in uranium alkyl complexes supported by ferrocene diamide ligands. Organometallics 27, 1702–1706 (2008).

    Article  CAS  Google Scholar 

  28. Fraenk, W. et al. Pentafluorophenyl and phenyl substituted azidoborates. Can. J. Chem. 80, 1444–1450 (2002).

    Article  CAS  Google Scholar 

  29. Crevier, T. J. & Mayer, J. M. Insertion of an osmium nitride into boron–carbon bonds. Angew. Chem. Int. Ed. 37, 1891–1893 (1998).

    Article  CAS  Google Scholar 

  30. Evans, W. J. et al. A crystallizable f-element tuck-in complex: the tuck-in tuck-over uranium metallocene [(C5Me5)U{μ-η5:η1:η1-C5Me3(CH2)2}(μ-H)2U(C5Me5)2]. Angew. Chem. Int. Ed. 47, 5075–5078 (2008).

    Article  CAS  Google Scholar 

  31. Gardner, B. M. et al. A crystallizable dinuclear tuck-in-tuck-over tuck-over dialkyl tren uranium complex and double dearylation of BPh4 to give the BPh2-functionalized metallocycle [U{N(CH2CH2NSiMe3)2(CH2CH2NSiMe2CHBPh2)}(THF)]. J. Am. Chem. Soc. 131, 10388–10389 (2009).

    Article  CAS  Google Scholar 

  32. Arney, D. S. J., Burns, C. J. & Smith, D. C. Synthesis and structure of the first uranium(VI) organometallic complex. J. Am. Chem. Soc. 114, 10068–10069 (1992).

    Article  CAS  Google Scholar 

  33. Hayton, T. W. Metal–ligand multiple bonding in uranium: structure and reactivity. Dalton Trans. 39, 1145–1158 (2010).

    Article  CAS  Google Scholar 

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Acknowledgements

The authors thank the Los Alamos National Laboratory (LANL) G. T. Seaborg Institute for Transactinium Science for a postdoctoral fellowship to R.K.T., LANL for a Director's postdoctoral fellowship to T.C., and the Division of Chemical Sciences, Office of Basic Energy Science, Heavy Element Chemistry program and the LANL Laboratory Directed Research and Development (LDRD) program for funding. R. M. Chamberlin and D. L. Clark (both LANL) are thanked for helpful discussions.

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Contributions

R.K.T. synthesized and characterized the compounds and wrote the manuscript. B.L.S. collected single-crystal X-ray crystallographic data and solved the structures. T.C. and E.R.B. performed DFT calculations. D.E.M. aided in the analysis and interpretation of UV–vis–NIR spectral data. J.L.K. generated and managed the project and helped write the manuscript.

Corresponding authors

Correspondence to Enrique R. Batista or Jaqueline L. Kiplinger.

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The authors declare no competing financial interests.

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Supplementary information (PDF 1656 kb)

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Crystallographic data for compound 2 (CIF 16 kb)

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Crystallographic data for compound 3 (CIF 28 kb)

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Crystallographic data for compound 4 (CIF 18 kb)

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Crystallographic data for compound 5 (CIF 29 kb)

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Crystallographic data for compound 7 (CIF 25 kb)

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Thomson, R., Cantat, T., Scott, B. et al. Uranium azide photolysis results in C–H bond activation and provides evidence for a terminal uranium nitride. Nature Chem 2, 723–729 (2010). https://doi.org/10.1038/nchem.705

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