Advertisement

Structural Chemistry

, Volume 18, Issue 5, pp 703–708 | Cite as

The use of chemical shifts vs. coupling constants for studying tautomerism: a combined experimental and theoretical approach

  • Dionisia Sanz
  • Rosa M. Claramunt
  • Ibon Alkorta
  • José Elguero
Original Paper

Abstract

When observing average NMR signals originated from a rapid equilibrium, the procedure to estimate the composition of the mixture is to use interpolation. To illustrate the difficulties of this approach, the much-studied case of the NH and OH tautomers of pyrazolinones will be reexamined. Calculated absolute shieldings and coupling constants were compared with experimental data. Although the large predominance of the OH tautomer in DMSO was confirmed, the result is a little disappointing because no consistency in the percentages was achieved using chemical shifts and coupling constants.

Keywords

13C NMR 15N NMR CP/MAS GIAO Coupling constants Tautomerism 

Notes

Acknowledgments

Thanks are given to MCyT (project number BQU2003-00976) and to MEC (project number CTQ2006-02586) of Spain for financial support.

References

  1. 1.
    Claramunt RM, López C, Santa María MD, Sanz D, Elguero J (2006) Prog Nucl Magn Reson Spectrosc 49:169CrossRefGoogle Scholar
  2. 2.
    Minkin VI, Garnovskii AD, Elguero J, Katritzky AR, Denisko OV (2000) Adv Heterocycl Chem 76:157CrossRefGoogle Scholar
  3. 3.
    Hawkes GE, Randall EW, Elguero J, Marzin CJ (1977) J Chem Soc Perkin Trans 2:1024Google Scholar
  4. 4.
    Ditchfield R (1974) Mol Phys 27:789. London F (1937) J Phys Radium 8:397Google Scholar
  5. 5.
    Alderete JB, Belmar J, Parra M, Zúñiga C (2000) Bol Soc Chil Quím 45:85Google Scholar
  6. 6.
    Belmar J, Alderete JB, Zúñiga C, Jiménez C, Jiménez H, Núñez H, Grandy R, Yori A (2001) Bol Soc Chil Quím 46:459Google Scholar
  7. 7.
    Kleinpeter E, Koch E (2001) J Phys Org Chem 14:566. Kleinpeter E, personal letter to the author (JE) of May 30, 2006Google Scholar
  8. 8.
    Dudek GO, Dudek EP (1966) J Am Chem Soc 88:2407CrossRefGoogle Scholar
  9. 9.
    Claramunt RM, Sanz D, Alarcón SH, Pérez-Torralba M, Elguero J, Foces-Foces C, Pietrzak M, Langer U, Limbach HH (2001) Angew Chem Int Ed 40:420CrossRefGoogle Scholar
  10. 10.
    Pietrzak M, Limbach HH, Pérez-Torralba M, Sanz D, Claramunt RM, Elguero J (2001) Magn Reson Chem 39:S100CrossRefGoogle Scholar
  11. 11.
    Sanz D, Pérez-Torralba M, Alarcón SH, Claramunt RM, Foces-Foces C, Elguero J (2002) J Org Chem 67:1462CrossRefGoogle Scholar
  12. 12.
    Holzer W, Kautsch C, Laggner C, Claramunt RM, Pérez-Torralba M, Alkorta I, Elguero J (2004) Tetrahedron 60:6791CrossRefGoogle Scholar
  13. 13.
    Berger S, Braun S (2004) 200 and more NMR experiments. Wiley-VCH, WeinheimGoogle Scholar
  14. 14.
    Becke AD (1993) J Chem Phys 98:5648. Lee C, Yang W, Parr RG (1988) Phys Rev B 37:785Google Scholar
  15. 15.
    Hariharan PA, Pople JA (1973) Theor Chim Acta 28:213CrossRefGoogle Scholar
  16. 16.
    Gaussian 03, Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Montgomery Jr JA, Vreven T, Kudin KN, Burant JC, Millam JM, Iyengar SS, Tomasi J, Barone V, Mennucci B, Cossi M, Scalmani G, Rega N, Petersson GA, Nakatsuji H, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Klene M, Li X, Knox JE, Hratchian HP, Cross JB, Adao C, Jaramill, J, Gomperts R, Stratmann RE, Yazyev O, Austin AJ, Cammi R, Pomelli C, Ochterski JW, Ayala PY, Morokuma K, Voth GA, Salvador P, Dannenberg JJ, Zakrzewski VG, Dapprich S, Daniels AD, Strain MC, Farkas O, Malick DK, Rabuck AD, Raghavachari K, Foresman JB, Ortiz JV, Cui Q, Baboul AG, Clifford S, Cioslowski J, Stefanov BB, Liu G, Liashenko A, Piskorz P, Komaromi I, Martin RL, Fox DJ, Keith T, Al-Laham MA, Peng CY, Nanayakkara A, Challacombe M, Gill PMW, Johnson B, Chen W, Wong MW, Gonzalez C, Pople JA (2003) Gaussian, Inc., Pittsburgh PAGoogle Scholar
  17. 17.
    Frisch MJ, Pople JA, Krishnam R, Binkley JS (1984) J Chem Phys 80:3265Google Scholar
  18. 18.
    Foces-Foces C, Fontenas C, Elguero J, Sobrados I (1997) An Quím Int Ed 93:219Google Scholar
  19. 19.
    Begtrup M, Boyer G, Cabildo P, Cativiela C, Claramunt RM, Elguero J, García JI, Toiron C, Vedsø P (1993) Magn Reson Chem 31:107CrossRefGoogle Scholar
  20. 20.
    Begtrup M, Balle T, Claramunt RM, Sanz D, Jiménez JA, Mó O, Yáñez M, Elguero J (1998) J Mol Struct (Theochem) 453:255CrossRefGoogle Scholar
  21. 21.
    Claramunt RM, Sanz D, López C, Jiménez JA, Jimeno ML, Elguero J, Fruchier A (1997) Magn Reson Chem 35:35CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Dionisia Sanz
    • 1
  • Rosa M. Claramunt
    • 1
  • Ibon Alkorta
    • 2
  • José Elguero
    • 2
  1. 1.Departamento de Química Orgánica y Bio-Orgánica, Facultad de CienciasUniversidad Nacional de Educación a Distancia (UNED)MadridSpain
  2. 2.Instituto de Química MédicaConsejo Superior de Investigaciones Científicas (CSIC)MadridSpain

Personalised recommendations