Skip to main content
SpringerLink
Log in

Reactivity of halides with triplets of 6-chloro and 6-bromopicolinic acids: contrasting effects of bromide and chloride

  • Paper
  • Published:
Photochemical & Photobiological Sciences Aims and scope Submit manuscript

Abstract

The reactivity of Br− and Cl− with triplet of anionic 6-chloropicolinic acid (pH = 5.4) and with triplets of 6-chloro and 6-bromopicolinic acids in zwitterionic forms (pH = 0.9) was studied by laser flash photolysis and steady-state irradiation. Br− was found to trap the three triplets. Triplet lifetime measurements gave quenching rate constants of 8 × 108 mol−1 dm3 s−1 for the zwitterion of 6-chloropicolinic acid and of 3.4 × 105 mol−1 dm3 s−1 for the anionic counterpart. No secondary transient species were observed indicating that the charge transfer intermediates are subject to dissipative processes. Cl− trapped triplet of zwitterions only, and reactions were found to be associated with a high quantum yield of radicals. The photolysis of 6-bromopicolinic acid photolysis was drastically enhanced by Cl−, 6-chloropicolinic acid being produced with a chemical yield of about 90%. The 6-bromo-2-carboxypyridinyl radical could be characterized (λmax/nm = 318 with shoulder at 370 nm and ε/mol−1 dm3 cm−1 = 8100).

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. M. Anbar, and J. K. Thomas, Pulse radiolysis studies of aqueous sodium chloride solutions, J. Phys. Chem., 1964, 68(12), 3829–3835.

    Article  CAS  Google Scholar 

  2. J. C. Scaiano, M. Barra, G. Calabrese, and R. Sinta, Photochemistry of 1,2-dibromoethane in solution. A model for the generation of hydrogen bromide, J. Chem. Soc., Chem. Commun., 1992, 1418–1419.

    Google Scholar 

  3. G. G. Jayson, B. J. Parsons, and A. J. Swallow, Simple, highly reactive, inorganic chlorine derivatives in aqueous solution. Formation using pulses of radiation and their role in the mechanism of the Fricke dosimeter, J. Chem. Soc., Faraday Trans. 1, 1973, 69(9), 1597–1607.

    Article  CAS  Google Scholar 

  4. L. I. Grossweiner, and M. S. Matheson, The kinetics of the dihalide ions from the flash photolysis of aqueous alkali halide solutions, J. Phys. Chem., 1957, 61, 1089–1095.

    Article  CAS  Google Scholar 

  5. G. Bartocci, and G. Favaro, Excited state reactivity of azaaromatics. VII: production and quenching of triplet naphthylpyridylethylene induced by halide anions, J. Photochem., 1979, 11(2), 79–86.

    Article  CAS  Google Scholar 

  6. H. Shizuka, M. Nakamura, and T. Morita, Anion-induced fluorescence quenching of aromatic molecules, J. Phys. Chem., 1980, 84, 989–994.

    Article  CAS  Google Scholar 

  7. A. Treinin, and E. Hayon, Quenching of triplet states by inorganic ions. Energy transfer and charge transfer mechanisms, J. Am. Chem. Soc., 1976, 98(13), 3884–3891.

    Article  CAS  Google Scholar 

  8. J. K. Hurley, H. Linschitz, and A. Treinin, Interaction of halide and pseudohalide ions with triplet benzophenone-4-carboxylate: kinetics and radical yields, J. Phys. Chem., 1988, 92, 5151–5159.

    Article  CAS  Google Scholar 

  9. F. Rollet, C. Richard, and J. F. Pilichowski, Photochemistry of 6-chloro and 6-bromopicolinic acids in water. Heterolytic vs. homolytic photodehalogenation, Photochem. Photobiol. Sci., 2006, 5, 88–94.

    Article  CAS  Google Scholar 

  10. Calculated using Advanced Chemistry Development (ACD/Labo) software Solaris V4.67, 1994–2005, data base of Chemical Abstracts Service

  11. F. Bonnichon, and C. Richard, Phototransformation of 3-hydroxybenzonitrile in water, J. Photochem. Photobiol., A, 1998, 119, 25–32.

    Article  CAS  Google Scholar 

  12. G. Grabner, personal communication.

  13. G. R. Dey, D. B. Naik, K. Kishore, and P. N. Moorthy, Reactions of hydrated electron, atomic hydrogen, and hydroxyl radical with picolinic acid studied by pulse radiolysis, J. Radioanal. Nucl. Chem., 1992, 163(2), 391–400.

    Article  CAS  Google Scholar 

  14. S. Solar, W. Solar, N. Getoff, J. Holeman, and K. Sehested, Reactivity of atomic hydrogen, hydroxyl radicals, and solvated electrons with nicotinic acid: a pulse radiolysis study, Radiat. Phys. Chem., 1988, 32, 585–592.

    CAS  Google Scholar 

  15. G. G. Wubbels, E. J. Snyder, and E. B. Coughlin, HCl-catalyzed photoreduction of 4-bromonitrobenzene as a concomitant of nucleophilic aromatic photosubstitution involving radical intermediates, J. Am. Chem. Soc., 1988, 110, 2543–2548.

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Laboratoire de Photochimie Moléculaire et Macromoléculaire, UMR n°6505 CNRS-Université Blaise Pascal, Ensemble Universitaire des Cézeaux, F-63177, Aubière Cedex, France

    Florence Rollet & Claire Richard

Authors
  1. Florence Rollet
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Claire Richard
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Claire Richard.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Rollet, F., Richard, C. Reactivity of halides with triplets of 6-chloro and 6-bromopicolinic acids: contrasting effects of bromide and chloride. Photochem Photobiol Sci 5, 674–679 (2006). https://doi.org/10.1039/b601319h

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1039/b601319h

Search

Navigation