Theoretica chimica acta

, Volume 63, Issue 3, pp 177–194 | Cite as

TheT1 state ofp-nitroaniline and related molecules: A CNDO/S study

  • Richard W. Bigelow
  • Hans-Joachim Freund
  • Bernhard Dick
Original Investigations

Abstract

The nature of the lowest energy triplet state (T1) ofp-nitroaniline (PNA), N,N-dimethyl-p-nitroaniline (DMPNA) and nitrobenzene (NB) is reexamined using the semiempirical CNDO/S-CI method with selected parameter options. The present results indicate that in the case of theunperturbed molecules the short-axis polarized π* ←n(π) triplet largely localized at the acceptor end of the molecule may lie lower in energy than the triplet manifold counterpart of the intense intramolecular charge-transferD+Asinglet excitation. Computations suggest, however, that polar solvents strongly stabilize the PNA and DMPNA π* ← π charge-transfer triplet relative to other excitations, whereas specific solvent hydrogen-bonded interactions stabilize the π* ←n(σ) triplet of NB below those of π* ← π character. These assignments allow a rationalization of phosphorescence lifetime data,T n T1 absorption measurements and relative photochemical behavior.

Key words

p-nitroaniline Nitrobenzene Triplet state Photo reductions Quantum Yield Solvent shifts 

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References and Notes

  1. 1.
    Khalil, O. S., Meeks, J. L., McGlynn, S. P.: J. Am. Chem. Soc.95, 5876 (1973)Google Scholar
  2. 2.
    Khalil, O. S., Seliskar, C. J., McGlynn, S. P.: J. Chem. Phys.58, 1607 (1973)Google Scholar
  3. 3.
    Seliskar, C. J., Khalil, O. S., McGlynn, S. P.: Excited states, Vol. 1, p. 231–294, Lim, E. C., Ed. New York: Academic Press, 1974Google Scholar
  4. 4.
    Khalil, O. S., Seliskar, C. J., McGlynn, S. P.: J. Mol. Spect.70, 74 (1978)Google Scholar
  5. 5.
    Carsey, T. P., Findley, G. L., McGlynn, S. P.: J. Am. Chem. Soc.101, 4502 (1979)Google Scholar
  6. 6.
    Findley, G. L., Carsey, T. P., McGlynn, S. P.: J. Am. Chem. Soc.101, 4511 (1979).Google Scholar
  7. 7.
    Wolleben, J., Testa, A. C.: J. Phys. Chem.81, 429 (1977)Google Scholar
  8. 8.
    Bigelow, R. W.: J. Chem. Phys.73, 3864 (1980)Google Scholar
  9. 9.
    Pignataro, S., Distefano, G.: J. Elect. Spect. Rel. Phenom.2, 171 (1973)Google Scholar
  10. 10.
    Pignataro, S., DiMarino, R., Distefano, G.: J. Elect. Spect. Rel. Phenom.4, 90 (1974)Google Scholar
  11. 11.
    Pignataro, S., Distefano, G.: Z. Naturforsch.30A, 815 (1975)Google Scholar
  12. 12.
    Tsuchiya, S., Seno, M.: Chem. Phys. Letters54, 132 (1978)Google Scholar
  13. 13.
    Domcke, W., Cederbaum, L. S., Schirmer, J., von Niessen, W.: Chem. Phys.39, 149 (1979)Google Scholar
  14. 14.
    Banna, M. S.: Chem. Phys.45, 383 (1980)Google Scholar
  15. 15.
    Bigelow, R. W., Freund, H.-J.: Chem. Phys. Letters77, 261 (1981)Google Scholar
  16. 16.
    Freund, H.-J., Bigelow, R. W.: Chem. Phys.55, 407 (1981)Google Scholar
  17. 17.
    Morrell, J. A., Albrecht, A. C.: Chem. Phys. Letters64, 46 (1979)Google Scholar
  18. 18.
    Lalama, S. J., Garito, A. F.: Phys. Rev.A20, 1179 (1979)Google Scholar
  19. 19.
    Levine, B. F.: J. Chem. Phys.63, 115 (1975)Google Scholar
  20. 20.
    Levine, B. F.: Chem. Phys. Letters37, 516 (1976)Google Scholar
  21. 21.
    Oudar, J. L., Chemla, D. S.: J. Chem. Phys.66, 2664 (1977)Google Scholar
  22. 22.
    Oudar, J. L.: J. Chem. Phys.67, 446 (1977)Google Scholar
  23. 23.
    Levine, B. F., Bethea, C. G.: J. Chem. Phys.69, 5240 (1978)Google Scholar
  24. 24.
    Nishimoto, K., Mataga, N.: Z. Phys. Chem. (Frankfurt am Main)12, 335 (1957)Google Scholar
  25. 25.
    Smith, H. E., Cozart, W. I., dePaulis, T., Chen, F. M.: J. Am. Chem. Soc.101, 5186 (1979). These workers argue in favor of low-lying PNA π** ←n(σ) singlet excitations based on a comparison of independent CNDO/S-CI results with the PNA crystal spectrumGoogle Scholar
  26. 26.
    In this regard our results parallel those of Plotnikov, V. G. and Komarov, V. M.: Spect. Letters9, 265 (1976). It should be noted, however, that Plotnikov and Komarov do not mention a D+A triplet π* ← π intramolecular charge-transfer excitation, although their work explicitly yields such character for theS 1 stateGoogle Scholar
  27. 27.
    As discussed in the text theT 1 state we define for the unperturbed molecules in this study is derived from a π-orbital lone-pair completely localized on the oxygen centers. According to Sidman, J. W.: Chem. Rev.58, 689 (1958), for example, any orbital largely localized in space can be properly classified as lone-pair (n), wheren may be either parallel to,n(π), or orthogonal to,n(σ), the main π-electron framework. We emphasize this point here because it appears that in the literature such ann-orbital distinction, particularly in regard to the nitroanilines, has often been reserved forn(σ)-type orbitals (see Refs [5] and [24], for example). For simplicity, however, we also reserve then classification primarily forn(σ)-type orbitals and explicitly indicate the lone-pair nature of the oxygen π-orbital in question asn(π) whenever failure to do so would cause some confusionGoogle Scholar
  28. 28.
    Parr, R. G.: J. Chem. Phys.20, 1499 (1952)Google Scholar
  29. 29.
    Pariser, R., Parr, R. G.: J. Chem. Phys.21, 767 (1953)Google Scholar
  30. 30.
    DelBene, J., Jaffé, H. H.: J. Chem. Phys.48, 1807, 4050 (1968);49, 1221 (1968);50, 1126 (1969)Google Scholar
  31. 31.
    Ellis, R. L., Kuehnlenz, G., Jaffé, H. H.: Theoret. Chim. Acta (Berl.)26, 131 (1972)Google Scholar
  32. 32.
    Dick, B., Hohlneicher, G.: Theoret. Chim. Acta (Berl.)53, 221 (1979)Google Scholar
  33. 33.
    Dick, B.: Chem. Phys., to be submitted for publicationGoogle Scholar
  34. 34.
    Pople, J. A., Beveridge, D. L.: Approximate molecular orbital theory, p. 111. New York: McGraw-Hill, 1970Google Scholar
  35. 35.
    Jacques, P., Faure, J., Chalvet, O., Jaffé, H. H.: J. Phys. Chem.85, 473 (1981)Google Scholar
  36. 36.
    Bertinelli, F., Polmieri, P., Brillante, A., Taliani, C.: Chem. Phys.25, 333 (1977)Google Scholar
  37. 37.
    Davis, L. P., Guidry, R. M.: Aust. J. Chem.32, 1369 (1979)Google Scholar
  38. 38.
    Masmanidis, C. A., Jaffé, H. H., Ellis, R. L.: J. Phys. Chem.79, 2052 (1975).Google Scholar
  39. 39.
    Chang, H. M., Jaffé, H. H.: Chem. Phys. Letters23, 146 (1973)Google Scholar
  40. 40.
    Koutecky, J.: J. Chem. Phys.47, 1501 (1967)Google Scholar
  41. 42.
    Roothaan, C. C. J.: Rev. Mod. Phys.23, 69 (1951)Google Scholar
  42. 43.
    Oikawa, S., Tsuda, M., Ueno, N., Sugita, K.: Chem. Phys. Letters74, 379 (1980)Google Scholar
  43. 44.
    Ito, H., I'Haya, Y.: Bull. Chem. Soc. Japan49, 940 (1976)Google Scholar
  44. 45.
    Suzuki, H.: Electronic absorption spectra and geometry of organic molecules, pp. 190–192; 430. New York: Academic Press, 1967Google Scholar
  45. 46.
    Lewis, G. N., Kasha, M.: J. Am. Chem. Soc.66, 2100 (1944)Google Scholar
  46. 47.
    Hurley, R., Testa, A. C.: J. Am. Chem. Soc.90, 1949 (1968)Google Scholar
  47. 48.
    Khalil, O. S., Bach, H. G., McGlynn, S. P.: J. Mol. Spect.35, 455 (1970)Google Scholar
  48. 49.
    McGlynn, S. P., Azumi, T., Kinoshita, M.: Molecular spectroscopy of the triplet state. New Jersey: Prentice-Hall, 1969Google Scholar
  49. 50.
    Hochstrasser, R. M.: Molecular aspects of symmetry. New York: Benjamin, 1966Google Scholar
  50. 51.
    Wild, U.P.: Topics in Current Chem.55, 1 (1975)Google Scholar
  51. 52.
    Jano, I.: Compt. Rend. Acad. Sci. Paris261, 103 (1965)Google Scholar
  52. 53.
    Lim, E. C., Chakrabarti, S. K.: Chem. Phys. Letters1, 28 (1967)Google Scholar
  53. 54.
    Döpp, D.: Topics in Current Chem.55, 49 (1975)Google Scholar
  54. 56.
    Khalil, O. S., McGlynn, S. P.: J. Luminescence11, 185 (1975/76)Google Scholar
  55. 57.
    Ledger, M. B., Suppan, P.: Spectrochim. Acta23A, 641 (1967)Google Scholar
  56. 58.
    Nagakura, S., Kojima, M., Maruyama, Y.: J. Mol. Spectros.13, 174 (1964)Google Scholar
  57. 59.
    Vidal, B., Murreil, J. N.: Chem. Phys. Letters31, 46 (1975)Google Scholar
  58. 60.
    Wiberg, K. B.: Physical organic chemistry, p. 189. New York: Wiley, 1964Google Scholar
  59. 61.
    Ref. [49], pp. 246–247Google Scholar
  60. 62.
    Vanquickenborne, L., McGlynn, S. P.: J. Chem. Phys.43, 4755 (1966)Google Scholar
  61. 63.
    Mataga, N., Kubota, T.: Molecular interactions and electronic spectra. New York: Marcel Dekker, Inc., 1970Google Scholar

Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • Richard W. Bigelow
    • 1
  • Hans-Joachim Freund
    • 2
  • Bernhard Dick
    • 2
  1. 1.Xerox Webster Research CenterWebsterUSA
  2. 2.Lehrstuhl für Theoretische Chemie der Universität zu KölnKölnFederal Republic of Germany

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