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Roaming-mediated isomerization in the photodissociation of nitrobenzene

Nature Chemistry volume 3, pages 932–937 (2011)Cite this article

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Abstract

Roaming reactions comprise a new class of reaction in which a molecule undergoes frustrated dissociation to radicals, followed by an intramolecular abstraction reaction. Nitro compounds have long been known to dissociate to give NO as a major product. However, rates based upon isomerization via calculated tight transition states are implausibly slow, so the key dissociation pathway for this important class of molecules remains obscure. Here, we present an imaging study of the photodissociation of nitrobenzene with state-specific detection of the resulting NO products. We observe a bimodal translational energy distribution in which the slow products are formed with low NO rotational excitation, and the fast component is associated with high rotational excitation. High-level ab initio calculations identified a ‘roaming-type’ saddle point on the ground state. Branching ratio calculations then show that thermal dissociation of nitrobenzene is dominated by ‘roaming-mediated isomerization’ to phenyl nitrite, which subsequently decomposes to give C6H5O + NO.

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Figure 1: Direct current sliced images of NO from the photodissocation of nitrobenzene excitation at ~226 nm.
Figure 2: Total translational energy distributions derived from the images in Fig. 1.
Figure 3: State-correlated plot showing NO(J) versus total translational energy or relative velocity derived from analysis of the images.
Figure 4: Schematic potential surfaces for the ground singlet and lowest triplet states of nitrobenzene.
Figure 5: Plot of the branching ratio for dissociation of nitrobenzene versus energy relative to the simple bond fission threshold (loss of NO2).

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References

  1. Schuler, V. H. & Woeldike, A. Phys. Z. 45, 171 (1944).

    CAS  Google Scholar 

  2. Hastings, S. H. & Matsen, F. A. The photodecomposition of nitrobenzene. J. Am. Chem. Soc. 70, 3514–3515 (1948).

    Article  CAS  Google Scholar 

  3. Matveev, V. G. & Nazin, G. M. Kinetics and mechanism of the decomposition of nitrobenzene in the gas phase. Bull. Acad. Sci. USSR Div. Chem. Sci. 24, 697–700 (1975).

    Article  Google Scholar 

  4. Gonzalez, A. C., Lamon, C. W., McMillen, D. F. & Golden, D. M. Mechanism of decomposition of nitroaromatics. Laser-powered homogeneous pyrolysis of substituted nitrobenzenes. J. Phys. Chem. 89, 4809–4814 (1985).

    Article  CAS  Google Scholar 

  5. Tsang, W., Rodaugh, D. & Mallard, W. G. Single-pulse shock-tube studies on C–NO2 bond cleavage during the decomposition of some nitro aromatic compounds. J. Phys. Chem. 90, 5968–5973 (1986).

    Article  CAS  Google Scholar 

  6. Porter, G. & Ward, B. The photolytic preparation of cyclopentadienyl and phenyl nitrene from benzene derivatives. Proc. R. Soc. London Ser. A 303, 139–156 (1968).

    Article  CAS  Google Scholar 

  7. Galloway, D. B., Bartz, J. A., Huey, L. G. & Crim, F. F. Pathways and kinetic disposal in the photodissociation of nitrobenzene. J. Chem. Phys. 98, 2107–2115 (1993).

    Article  CAS  Google Scholar 

  8. Galloway, D. B., Glenewinkel-Meyer, T., Bartz, J. A., Huey, L. G. & Crim, F. F. The kinetic and internal energy of NO from the photodissociation of nitrobenzene. J. Chem. Phys. 100, 1946–1953 (1994).

    Article  CAS  Google Scholar 

  9. Lin, M. F., Lee, Y. T., Ni, C.-K., Xu, S. & Lin, M. C. Photodissociation dynamics of nitrobenzene and o-nitrotoluene. J. Chem. Phys. 126, 64310–64321 (2007).

    Article  Google Scholar 

  10. Marshall, A., Clark, A., Jennings, R., Ledingham, K. W. D. & Singhal, R. P. J. Mass. Spectrom. Ion Proc. 135, 229–242 (1992).

    Google Scholar 

  11. Suits, A. G. Roaming atoms and radicals: a new mechanism in molecular dissociation. Acc. Chem. Res. 41, 873–881 (2008).

    Article  CAS  Google Scholar 

  12. Suits, A. G., Chambreau, S. D. & Lahankar, S. A. State-correlated d.c. slice imaging of formaldehyde photodissociation: roaming atoms and multichannel branching. Int. Rev. Phys. Chem. 26, 585–607 (2007).

    Article  CAS  Google Scholar 

  13. Houston, P. L. & Kable, S. H. Dissociation of acetaldehyde at 308 nm: another example of the ‘roaming’ mechanism? Proc. Natl Acad. Sci. USA 16079–16082 (2006).

  14. van Zee, R. D., Foltz, M. F. & Moore, C. B. Evidence for a 2nd molecular channel in the fragmentation of formaldehyde. J. Chem. Phys. 99, 1664–1673 (1993).

    Article  CAS  Google Scholar 

  15. Herath, N. & Suits, A. G. Roaming radical reactions. J. Phys. Chem. Lett. 2, 642–647 (2011).

    Article  CAS  Google Scholar 

  16. Grubb, M. P., Warter, S. C., Suits, A. G. & North, S. W. Evidence of roaming dynamics and multiple channels for molecular elimination in NO3 photolysis. J. Phys. Chem. Lett. 1, 2455–2458 (2010).

    Article  CAS  Google Scholar 

  17. Zhu, R. S. & Lin, M. C. CH3NO2 decomposition/isomerization mechanism and product branching ratios: an ab initio chemical kinetic study. Chem. Phys. Lett. 478, 11–16 (2009).

    Article  CAS  Google Scholar 

  18. Xu, S. & Lin, M. C. Computational study on the kinetics and mechanism for the unimolecular decomposition of C6H5NO2 and the related C6H5+NO2 and C6H5O+NO reactions. J. Phys. Chem. B 109, 8368–8373 (2005).

    Google Scholar 

  19. Fayet, G., Jounert, L., Rotureau, P. & Adamo, C. Theoretical study on the decomposition reactions in substituted nitrobenzenes. J. Phys. Chem. A 112, 4054–4059 (2008).

    Article  CAS  Google Scholar 

  20. Castle, K. J., Abbott, J. E., Peng, X. & Kong, W. Photodissociation of o-nitrotoluene between 220 and 250 nm in a uniform electric field. J. Phys. Chem. A 104, 10419–10425 (2000).

    Article  CAS  Google Scholar 

  21. Chen, S. C., Xu, S. C., Diau, E. & Lin, M. C. A computational study on the kinetics and mechanism for the unimolecular decomposition of o-nitrotoluene. J. Phys. Chem. A 110, 10130–10134 (2006).

    Article  CAS  Google Scholar 

  22. Johns, J. W. C., Reid, J. & Lepard, D. W. The vibration-rotation fundamental of NO. J. Mol. Spectrosc. 65, 155–162 (1977).

    Article  CAS  Google Scholar 

  23. Xiao, H., Maeda, S. & Morokuma, K. Excited-state roaming dynamics in photolysis of a nitrate radical. J. Phys. Chem. Lett. 2, 934–938 (2011).

    Article  CAS  Google Scholar 

  24. Townsend, D., Minitti, M. P. & Suits, A. G. Direct current slice imaging. Rev. Sci. Instrum. 74, 2530–2539 (2003).

    Article  CAS  Google Scholar 

  25. Li, W., Chambreau, S. D., Lahankar, S. A. & Suits, A. G. Megapixel ion imaging with standard video. Rev. Sci. Instrum. 76, 63106–63113 (2005).

    Article  Google Scholar 

  26. Gonzalez, C. & Schlegel, H. B. An improved algorithm for reaction-path following. J. Chem. Phys. 90, 2154–2161 (1989).

    Article  CAS  Google Scholar 

  27. GAUSSIAN 09 (Revision A.1) (Gaussian, 2009).

  28. Wardlaw, D. M. & Marcus, R. A. RRKM reaction-rate theory for transition-states of any looseness. Chem. Phys. Lett. 110, 230–234 (1984).

    Article  CAS  Google Scholar 

  29. Klippenstein, S. J., Wagner, A. F., Robertson, S. H., Dunbar, R. & Wardlaw, D. M. Variflex software, Version 1.00 (1999); available at http://chemistry.anl.gov/variflex.

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Acknowledgements

This work was supported by the US Army Research Laboratory and the US Army Research Office (contract/grant no. W911NF-10-1-0531). R.S.Z. acknowledges funding from the Office of Naval Research (contract no. N000140810106) and M.C.L. thanks Taiwan's NSC and MoE/ATU programmes for their support. M.L.H. also acknowledges the Office of the Vice President for Research at Wayne State University for a post-doctoral fellowship. A.G.S. acknowledges many fruitful discussions with J.M. Bowman.

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Authors and Affiliations

  1. Department of Chemistry, Wayne State University, Detroit, 48202, Michigan, USA

    Michael L. Hause, Nuradhika Herath & Arthur G. Suits

  2. Department of Chemistry, Emory University, Atlanta, 30322, Georgia, USA

    Rongshun Zhu & M. C. Lin

  3. National Chiao Tung University, Hsinchu, Taiwan

    M. C. Lin

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  1. Michael L. Hause
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  2. Nuradhika Herath
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  4. M. C. Lin
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Contributions

M.H. analysed the data, performed experiments and wrote portions of the paper. N.H. performed experiments and analysed data. R.S.Z. performed the calculations. A.G.S. conceived and designed the experiments. M.C.L. conceived and designed the calculations. All authors contributed to writing sections of the paper.

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Correspondence to Arthur G. Suits.

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Hause, M., Herath, N., Zhu, R. et al. Roaming-mediated isomerization in the photodissociation of nitrobenzene. Nature Chem 3, 932–937 (2011). https://doi.org/10.1038/nchem.1194

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