Ligand dynamics in tetracoordinate copper(I) complexes of bis(pyrazolyl)pyridine ligands[hair space]

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

Palanichamy Manikandan, Mahadevan Subramoni, Babu Varghese and Periakaruppan ThangiahManoharan


Abstract

Several mononuclear and a binuclear copper(I)–phosphine complex with a tridentate ligand, L [2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine] or L′ [2,6-bis(pyrazol-1-ylmethyl)pyridine], have been prepared and characterized. The crystal structure of [LCu(PPh2CH2CH2PPh2)CuL][ClO4]2 has been solved. All complexes exhibit interesting molecular dynamics which could be monitored by 1H NMR spectral characteristics arising from the methylene group of the ligand and also from the protons of the pyrazole part of the ligand in some cases. The complexes with unsymmetric phosphine ligands such as PPhnBu3–n with n = 1 or 2 revealed the presence of two conformations with differing populations as evidenced by temperature dependent 1H NMR spectral data. The thermodynamics of these transformations due to the fluxional character of the ligand, L, has been studied by computer simulations of the experimental spectra. The NMR spectral characteristics revealed that the methylene protons are diastereotropic.


References

  1. K. D. Karlin and J. Tyeklsr(Editors), Bioinorganic Chemistry of Copper, Chapman & Hall, New York, 1993 Search PubMed.
  2. K. D. Karlin, R. W. Cruse, M. S. Haka and Y. Gultneh, Inorg. Chim. Acta., 1986, 125, L43 CrossRef CAS.
  3. K. D. Karlin, M. S. Haka, R. W. Cruse, G. J. Meyer, A. Faroog, Y. Gultneh, J. C. Hayes and J. Zubieta, J. Am. Chem. Soc., 1988, 110, 1196 CrossRef CAS.
  4. K. D. Karlin, R. W. Cruse, Y. Gultneh, J. C. Hayes and J. Zubieta, J. Am. Chem. Soc., 1984, 106, 3372 CrossRef CAS.
  5. N. J. Blackburn, R. W. Strange, A. Farooq, M. S. Haka and K. D. Karlin, J. Am. Chem. Soc., 1988, 110, 4263 CrossRef CAS.
  6. L. Casella, O. Carugo, M. Gullotti, S. Garofani and P. Zanello, Inorg. Chem., 1993, 32, 2056 CrossRef CAS.
  7. N. Kitajima and Y. Moro-oka, Chem. Rev., 1994, 94, 737 CrossRef CAS.
  8. N. Kitajima, K. Fujisawa and Y. Moro-oka, J. Am. Chem. Soc., 1989, 111, 8975 CrossRef CAS.
  9. E. I. Solomon, Copper Proteins, ed. T. G. Spiro, Wiley, New York, 1981 vol.3, pp. 41–108 Search PubMed.
  10. P. Manikandan, B. Varghese and P. T. Manoharan, J. Chem. Soc., Dalton Trans., 1996, 371 RSC.
  11. J. T. Gill, J. J. Mayerle, P. S. Welcker, D. F. Lewis, D. A. Ucko, D. J. Barton, D. Stowens and S. J. Lippard, Inorg. Chem., 1976, 15, 1155 CrossRef CAS.
  12. B. Mohr, E. E. Brooks, N. Rath and E. Deutsch, Inorg. Chem., 1991, 30, 4541 CrossRef CAS.
  13. M. R. Churchill and K. L. Kalra, Inorg. Chem., 1974, 13, 1065 CrossRef CAS.
  14. E. L. Muetterties, Inorg. Chem., 1965, 4, 769 CrossRef CAS.
  15. S. J. Berners-Price, C. K. Mirabelii, R. K. Johnson, L. F. Faucette, F. L. McCabe and P. J. Sadler, Inorg. Chem., 1987, 26, 3383 CrossRef CAS.
  16. R. K. Johnson, C. K. Mirabelli, L. F. Faucette, F. L. McCabe, B. M. Sutton, D. L. Bryan, G. R. Girard and D. T. Hill, Proc. Am. Assoc. Cancer Res., 1985, 26, 254 Search PubMed.
  17. J. Diez, M. P. Gamasca, J. Gimeno, A. Tiripichio and M. T. Camellini, J. Chem. Soc., Dalton Trans., 1987, 1275 RSC.
  18. J. A. Goodwin, L. J. Wilson, D. M. Stanbury and R. A. Scott, Inorg. Chem., 1989, 28, 42 CrossRef CAS.
  19. D. K. Coggin, J. A. Gonzalez, A. M. Kook, D. M. Stanbury and L. J. Wilson, Inorg. Chem., 1991, 30, 1115 CrossRef CAS.
  20. D. K. Coggin, J. A. González, A. M. Kook, C. Bergman, T. D. Brennan, W. R. Scheidt, D. M. Stanbury and L. J. Wilson, Inorg. Chem., 1991, 30, 1125 CrossRef CAS.
  21. G. Binsch, Dynamic Nuclear Magnetic Resonance Spectroscopy, eds. L. M. Jackaman and F. A. Cotton, Academic Press, New York, 1975, p. 45 Search PubMed.
  22. J. D. Salter, V. Šik, S. A. Williams and T. Adatia, J. Chem. Soc., Dalton Trans., 1996, 643 RSC.
  23. S. Gutoswky and Saiker, J. Chem. Phys., 1953, 21, 1688 CrossRef CAS.
  24. H. Kessler, Angew. Chem., Int. Ed. Engl., 1970, 9, 219 CrossRef CAS.
  25. G. Binsch and H. Kessler, Angew. Chem., Int. Ed. Engl., 1980, 19, 411 CrossRef.
  26. R. S. Drago, Physical Methods in Chemistry, W. B. Saunders Company, London, 1977 Search PubMed.
  27. G. J. Hawkins and J. A. Palmer, Coord. Chem. Rev., 1982, 44, 1 CrossRef CAS.
  28. D. F. Shriver and M. A. Drezdzon, Manipulation of air sensitive compounds, 2nd edn., Wiley-Interscience, New York, 1986 Search PubMed.
  29. D. D. Perrin and W. L. F. Armerego, Purification of laboratory chemicals, 3rd edn, Pergamon, New York, 1988 Search PubMed.
  30. S. Mahapatra, R. N. Gupta and N. Mukherjee, J. Chem. Soc., Dalton Trans., 1991, 2911 RSC.
  31. G. M. Sheldrick, Acta Crystallogr., Sect. A, 1990, 46, 467 CrossRef.
  32. G. M. Sheldrick, SHELXL 93, Program for Crystal Structure Refinement, University of Göttingen, 1993.
  33. L. Zsolnai and H. Pritzkowm, ORTEP program for personal computer, University of Heidelberg, 1994.
  34. R. H. Holm, Dynamic Nuclear Magnetic Resonance Spectroscopy, eds. L. M. Jackaman and F. A. Cotton, Academic Press, New York, 1975, p. 317 Search PubMed.
Click here to see how this site uses Cookies. View our privacy policy here.