Solvent and substituent effects on the fluorescent properties of coelenteramide analogues

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Ryota Saito, Takashi Hirano, Haruki Niwa and Mamoru Ohashi


Abstract

Coelenteramide 1 is the light emitter in aequorin bioluminescence. To establish the fluorescent character of 1, the fluorescence properties of 1 and a series of its analogues, 3a–f, possessing a substituent R [= CF3, F, H, OCH3, OH, N(CH3)2] at the para-position on the 5-phenyl group have been investigated in solvents of various polarity. The fluorescence emission maxima of 1 and 3d–f, possessing an electron-donating group R [= OCH3, OH, N(CH3)2] shift to lower energy with increasing solvent polarity, while those of the analogues 3a–c (R = CF3, F, H) are independent of the solvent polarity. The linear correlation between the fluorescence maxima of 1 and 3d–f and the solvent polarity scales can be explained by formation of the singlet excited state with a charge-transfer (CT) character. The quantum yields of CT fluorescence of 1 and 3d–f have been found to be higher than those of 3a–c. These results indicate that the solvatochromic fluorescence of 1 originates from the CT excited state and the existence of an electron donating hydroxy group on the 5-phenyl group is essential for determining a wavelength and a high fluorescence quantum yield of aequorin bioluminescence.


References

  1. (a) O. Shimomura, F. H. Johnson and Y. Saiga, J. Cell. Comp. Physiol., 1962, 59, 223 Search PubMed; (b) O. Shimomura and F. H. Johnson, Nature (London), 1970, 227, 1356 CAS; (c) F. H. Johnson and O. Shimomura, Methods Enzymol., 1978, 57, 71.
  2. O. Shimomura and F. H. Johnson, Nature (London), 1975, 256, 236 CAS.
  3. O. Shimomura and F. H. Johnson, Tetrahedron Lett., 1973, 2963 CrossRef.
  4. Y. Ohmiya, M. Ohashi and F. I. Tsuji, FEBS Lett., 1992, 301, 197 CrossRef CAS.
  5. T. Hirano, I. Mizoguchi, M. Yamaguchi, F. Q. Chen, M. Ohashi, Y. Ohmiya and F. I. Tsuji, J. Chem. Soc., Chem. Commun., 1994, 165 RSC.
  6. (a) F. McCapra and Y. C. Chang, J. Chem. Soc., Chem. Commun., 1967, 1011 RSC; (b) T. Goto, S. Inouye and S. Sugiura, Tetrahedron Lett., 1968, 3873 CrossRef CAS; (c) T. Goto, S. Inoue, S. Sugiura, K. Nishikawa, M. Isobe and Y. Abe, Tetrahedron Lett., 1968, 4035 CrossRef CAS; (d) F. McCapra and M. J. Manning, J. Chem. Soc., Chem. Commun., 1973, 467 RSC; (e) K. Hori, J. E. Wampler and M. J. Cormier, J. Chem. Soc., Chem. Commun., 1973, 492 RSC; (f) T. Hirano, Y. Gomi, T. Takahashi, K. Kitahara, F. Q. Chen, I. Mizoguchi, S. Kyushin and M. Ohashi, Tetrahedron Lett., 1992, 33, 5771 CrossRef CAS.
  7. O. Shimomura, Biochem. J., 1995, 306, 537 CAS.
  8. T. Goto and H. Fukatsu, Tetrahedron Lett., 1969, 4299 CrossRef CAS.
  9. Y. Kishi, H. Tanino and T. Goto, Tetrahedron Lett., 1972, 2747 CrossRef CAS.
  10. O. Shimomura, B. Musicki and Y. Kishi, Biochem. J., 1989, 261, 913 CAS.
  11. F. Q. Chen, Y. Gomi, T. Hirano, M. Ohashi, Y. Ohmiya and F. I. Tsuji, J. Chem. Soc., Perkin Trans 1, 1992, 1607 RSC.
  12. K. Teranishi and T. Goto, Bull. Chem. Soc. Jpn., 1989, 62, 2009 CAS.
  13. E. M. Kosower, H. Kanety, H. Dodiuk, G. Striker, T. Jovin, H. Boni and D. Huppert, J. Phys. Chem., 1983, 87, 2479 CrossRef CAS and references cited therein.
  14. R. M. Hermant, N. A. C. Bakker, T. Scherer, B. Krijnen and J. W. Verhoeven, J. Am. Chem. Soc., 1990, 112, 1214 CrossRef CAS.
  15. C. Reichardt, Solvents and Solvent Effects in Organic Chemistry, VCH, Weinheim, 2nd edn., 1988 Search PubMed.
  16. E. M. Kosower, H. Dodiuk, K. Tanizawa, M. Ottolenghi and N. Orbach, J. Am. Chem. Soc., 1975, 97, 2167 CrossRef CAS.
  17. Hammett σp values were taken from the following: C. Hansch, A. Leo and R. W. Taft, Chem. Rev., 1991, 91, 165 Search PubMed.
  18. E. M. Kosower, Acc. Chem. Res., 1982, 15, 259 CrossRef CAS.
  19. Y. Toya, T. Kayano, K. Sato and T. Goto, Bull. Chem. Soc. Jpn., 1992, 65, 2475 CAS.
  20. J. H. D. Eland, Int. J. Mass Spectrom. Ion Phys., 1969, 2, 471 CrossRef CAS.
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