View PDF Version
 
DOI: 10.1039/A606216D (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1997, 533-536

Solvent induced variations in nitrogen NMR shieldings of some oxime systems as a test of the Solvaton model of non-specific molecular interactions

(Note: The full text of this document is currently only available in the PDF Version )

Michal Witanowski, Zenobia Biedrzycka, Wanda Sicinska and Graham A. Webb

Abstract

High precision 14N NMR measurements are reported for three oxime systems in a variety of solvents. Both hydrogen bonding and solvent polarity effects are found to make significant contributions to the observed range of nitrogen shieldings. For a non-conjugated oxime moiety the solvent induced nitrogen shielding variations are found to be of opposite sign to those found for oximes which have a strongly conjugated carbonyl group. These shielding variations are interpreted in terms of solute–solvent specific and non-specific interactions. The analysis of the shielding data results in the view that, in these two cases of carbonyl group conjugation, there are opposing directions of electronic charge migration as a function of an increase in solvent polarity. There appears to be a change in the preference of the solute hydrogen bond acceptor site from the oxime to the carbonyl moiety in the case of p-benoquinone mono oxime derivatives. Medium polarity effects on the solute nitrogen shielding are adequately accounted for by INDO/S parametrised molecular orbital calculations of nitrogen shieldings as a function of solvent relative permittivity (ε) by means of the Solvaton model. This model describes satisfactorily the effects of a change in solvent polarity on the nitrogen shielding of a variety of nitrogen containing solutes.

References

  1. M. Witanowski, W. Sincinska, S. Biernat and G. A. Webb, J. Magn. Reson., 1991, 91, 289 CAS .
  2. M. Witanowski, W. Sicinska and G. A. Webb, J. Magn. Reson., 1992, 98, 109 CAS .
  3. M. Witanowski, W. Sicinska, Z. Grabowski and G. A. Webb, Magn. Reson. Chem., 1990, 28, 988 CAS .
  4. M. Witanowski, W. Sicinska, Z. Biedrzycka and G. A. Webb, J. Magn. Reson., 1994, 109A, 177 .
  5. M. Witanowski, W. Sicinska, Z. Biedrzycka, Z. Grabowski and G. A. Webb, J. Chem. Soc., Perkin Trans. 2, 1996, 619 RSC .
  6. M. Witanowski, Z. Biedrzycka, W. Sicinska, Z. Grabowski and G. A. Webb, J. Magn. Reson., 1996, 120A, 148 .
  7. M. Witanowski, W. Sicinska, Z. Biedrzycka, Z. Grabowski and G. A. Webb, J. Magn. Reson., 1995, 112A, 66 .
  8. M. Witanowski, W. Sicinska, Z. Grabowski and G. A. Webb, J. Magn. Reson., 1993, 104A, 310 .
  9. M. Witanowski, W. Sicinska and G. A. Webb, Spectrosc. Int. J., 1992, 10, 25 CAS .
  10. M. Witanowski, W. Sicinska and G. A. Webb, J. Mol. Struct., 1994, 321, 225 CrossRef CAS .
  11. M. Witanowski, W. Sicinska, S. Biernat and G. A. Webb, J. Magn. Reson., 1989, 83, 351 CAS .
  12. M. Witanowski, W. Sicinska and G. A. Webb, Spectrosc. Int. J., 1992, 10, 31 CAS .
  13. M. Witanowski, Z. Biedrzycka, W. Sicinska and G. A. Webb, J. Mol. Struct., 1994, 328, 253 CrossRef CAS .
  14. M. Witanowski, J. Sitkowski, S. Biernat, B. Kamienski, B. T. Hamdi and G. A. Webb, Magn. Reson. Chem., 1985, 23, 748 CAS .
  15. M. Witanowski, J. Sitkowski, S. Biernat, L. V. Sudha and G. A. Webb, Magn. Reson. Chem., 1987, 25, 725 CAS .
  16. M. Witanowski, W. Sicinska, Z. Biedrzycka and G. A. Webb, Magn. Reson. Chem., 1993, 31, 916 CAS .
  17. M. Witanowski, Z. Biedrzycka and G. A. Webb, Magn. Reson. Chem., 1996, 34, 233 CrossRef CAS .
  18. M. Witanowski, W. Sicinska and G. A. Webb, Magn. Reson. Chem., 1989, 27, 380 CAS .
  19. M. Witanowski, W. Sicinska and G. A. Webb, Magn. Reson. Chem., 1992, 30, 169 CAS .
  20. I. Ando and G. A. Webb, Theory of NMR Parameters, Academic Press, London, 1983 Search PubMed .
  21. Handbook of Chemistry and Physics, ed. R. C. Weast, CRC, Cleveland, OH, 64th edn., 1984, p. E–49 Search PubMed .
  22. M. H. Abraham, P. L. Grellier, J. L. M. Abboud, R. M. Doherty and R. W. Taft, Can. J. Chem., 1988, 66, 2673 CAS .
  23. Y. Marcus, Chem. Soc. Rev., 1993, 409 RSC .
  24. M. Witanowski, L. Stefaniak and G. A. Webb, Annual Reports on NMR Spectroscopy, Academic Press, London, 1993, 25, 41 Search PubMed .
  25. F. Stunnenberg and H. Cerfontain, J. Phys. Chem., 1987, 91, 6490 CrossRef CAS .
  26. M. Witanowski, L. Stefaniak and G. A. Webb, Annual Reports on NMR Spectroscopy, Academic Press, London, 1993, 25, 380 Search PubMed .
  27. A. I. Vogel, W. T. Creswell, G. H. Jeffery and J. Leicester, J. Chem. Soc, 1952, 514 RSC .
  28. S. Veibel and M. M. Simensen, Ber., 1930, 63, 2476 Search PubMed .
  29. E. Havinga and A. Schors, Recl. Trav. Pays-Bas, 1958, 69, 464 .
Click here to see how this site uses Cookies. View our privacy policy here.