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DOI: 10.1039/A902339I (Paper) Reference Section for: Chem. Commun., 1999, 1221-1222

Evidence for unusually strong intramolecular hydrogen bonding in highly nonplanar porphyrins

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Maria S. Somma, Craig J. Medforth, Nora Y. Nelson, Marilyn M. Olmstead, Richard G. Khoury and Kevin M. Smith

Abstract

The 1H NMR spectra of the 5,10,15,20-tetraalkylporphyrins 2–4 reveal a large downfield shift of the signal for the NH protons and a reduction in the activation energy for NH tautomerism as the alkyl substituents become larger; these unusual changes can be rationalized in terms of greatly enhanced intramolecular hydrogen bonding of the NH protons as the bulkier substituents distort the macrocycle from planarity and contract the porphyrin core.

References

  1. H. Scheer and J. J. Katz, in Porphyrins and Metalloporphyrins, ed. K. M. Smith, Elsevier, Amsterdam, 1975, 399 Search PubMed.
  2. T. R. Janson and J. J. Katz, in The Porphyrins, ed. D. Dolphin, Academic Press, New York, 1979, vol. 4, p. 1 Search PubMed.
  3. M. O. Senge, I. Bischoff, N. Y. Nelson and K. M. Smith, J. Porphyrins Phthalocyanines, 1999, 3, 99 CrossRef CAS.
  4. C. J. Medforth, in The Porphyrin Handbook, ed. K. M. Kadish, K. M. Smith and R. Guilard, Academic Press, Burlington, MA, 1999, in the press Search PubMed.
  5. W. Jentzen, M. C. Simpson, J. D. Hobbs, X. Song, T. Ema, N. Y. Nelson, C. J. Medforth, K. M. Smith, M. Veyrat, M. Mazzanti, R. Ramasseul, J.-C. Marchon, T. Takeuchi, W. A. Goddard III and J. A. Shelnutt, J. Am. Chem. Soc., 1995, 117, 11 085 CrossRef CAS.
  6. M. O. Senge, T. Ema and K. M. Smith, J. Chem. Soc., Chem. Commun., 1995, 733 RSC.
  7. C. J. Medforth, C. M. Muzzi, K. M. Shea, K. M. Smith, R. J. Abraham, S. Jia and J. A. Shelnutt, J. Chem. Soc., Perkin Trans. 2, 1997, 839 RSC.
  8. Z. Smedarchina, M. Z. Zgierski, W. Siebrand and P. W. Kozlowski, J. Chem. Phys., 1988, 109, 1014 CrossRef.
  9. E. Vogel, M. Kocher, H. Schmickler and J. Les, Angew. Chem., Int. Ed. Engl., 1986, 25, 257 CrossRef.
  10. X.-Z. Song, L. Jaquinod, W. Jentzen, D. J. Nurco, S. Jia, R. Khoury, J. Ma, C. J. Medforth, K. M. Smith and J. A. Shelnutt, Inorg. Chem., 1998, 37, 2009 CrossRef CAS.
  11. J. A. Shelnutt, X.-Z. Song, W. Jentzen, J.-G. Ma, S.-L. Jia, W. Jentzen and C. J. Medforth, Chem. Soc. Rev., 1998, 27, 31 RSC.
  12. D. J. Nurco, C. J. Medforth, T. P. Forsyth, M. M. Olmstead and K. M. Smith, J. Am. Chem. Soc., 1996, 118, 10 918 CrossRef CAS.
  13. J. Takeda and M. Sato, Chem. Lett., 1995, 971 CAS.
  14. S. Parkin, B. Moezzi and H. Hope, J. Appl. Crystallogr., 1995, 28, 53 CrossRef CAS.
  15. K. M. Barkigia, M. W. Renner, N. Y. Nelson, R. Khoury, K. M. Smith, D. Holten, M. C. Piqueras, C. M. Rohlfing, S. Jia, J. A. Shelnutt and J. Fajer, unpublished work.
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