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Theoretical study of intramolecular proton transfer of perylenequinone

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Abstract

AM1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, singlet excited state and triplet excited state of PQ are 89.75, 55.40 and 83.97 kJ/mol, respectively. (ii) Barriers a-gainst the IPT process of anion of PQ in ground state and singlet excited state are 80.12 and 79. 91 kJ/mol, respectively, (iii) Barriers against the IPT of cation and anion radical of PQ (PQ,+ and PC,-) are 65. 94 and 59.29 kJ/ mol. (iv) The barrier against double proton transfer of PQ is 172.13 kJ/mol. (v) Two barriers against IPT of a type of perylenequinonoid photosensitizer (PQP), hypocrellin A (HA), are 89. 24 and 88. 07 kJ/mol. From these data conclusions can be drawn as follows: (i) IPT processes in ground state and excited state of PQ exist, but the transfer rate of excited state is much higher than that of ground state. (ii) It is almost impossible for PQ to transfer two protons simultaneously. (iii) IPT processes in anion, anion radical and cation radical of PQ still exist. (iv) The seven-membered side ring of HA has no marked influence on its barrier against IPT.

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References

  1. Diwu, Z., Novel therapeutic and diagnostic applications of hypocrellins and hypericins,Photochem. Photobiol., 1995, 61(6): 529.

    CAS  Google Scholar 

  2. Hu, Y. Z., An, J. Y., Jiang, L. J. et al., Spectroscopic study on the photoreduction of hypocrellin A: generation of semiquinone radical anion and hydroquinone,J. Photochem. Photobiol., A:Chem., 1995, 89: 45.

    Article  CAS  Google Scholar 

  3. Diwu, Z., Lown, J. W., Photosensitization with anticancer agents (15) —Perylenequinonoid pigments as potential photodynamic therapeutic agents: formation of semiquinone radicals and reactive oxygen species on illumination,J. Photochem. Photobiol. B:Biol., 1993, 18: 131.

    Article  CAS  Google Scholar 

  4. Gai, F., Fehr, M. J., Petrich, J. W., Observation of excited-state tautomerization in the antivirul agent hypericin and identification of its fluorescent species,J. Phys. Chem., 1994, 98: 5784.

    Article  CAS  Google Scholar 

  5. Gajewski, J. J., Gillbert, K. E., Mckelvey, J, MMX: an enhanced version of MM2,Adv. Mol. Model, 1990, 2: 65.

    CAS  Google Scholar 

  6. Dewar, M. J. S., Zoebisch, E. G., Healy, E. F. et al., AM1: a new general purpose quantum mechanical molecular model,J. Am. Chem. Soc., 1985, 107: 3902.

    Article  CAS  Google Scholar 

  7. Rossetti, R., Haddon, R. C., Brus, L. E., Intramolecular proton tunnelling in the ground and lowest excited singlet states of 9-hydroxyphenalenone,J. Am. Chem. Soc., 1980, 102: 6913.

    Article  CAS  Google Scholar 

  8. Kunze, K. L., de la Vega, J. R., Intramolecular proton exchange in 9-hydroxyphenalen-1-one and methyl-9-hydroxyphenalen-1-one,J. Am. Chem. Soc., 1984, 106(22): 6528.

    Article  CAS  Google Scholar 

  9. Diwu, Z., Jiang, L., Zhang, M. et al., The stereochemistry of hypocrellin A,Chin. Sci. Bull. (in Chinese), 1989, 34(14): 1073.

    Google Scholar 

  10. Zhang, H., Zhang, Z., Molecular mechanics study on conformation of perylenequinonoid photosensitizer,Science in China (in Chinese), Ser. B, 1997, 27(4): 358.

    Google Scholar 

  11. Zhang, H., Zhang, Z., Determination of pK a values of perylenequinonoid photosensitizer in excited state,Chin. Sci. Bull. (in Chinese), 1997, 42: 1428.

    Google Scholar 

  12. Yamazaki, T., Ohta, N., Yamazaki, I. L. et al., Excited-state properties of hypericin-electronic spectra and fluorescence dacay kinetics,J. Phys. Chem., 1993, 97: 7870.

    Article  CAS  Google Scholar 

  13. Freeman, D., Frolow, F., Kapinus, E. et al., Acidic properties of hypericin and its octahydroxy analog in the ground and excited states,J. Chem. Soc. Chem. Commun., 1994: 891.

  14. Diwu, Z., Lown, J. W., Photosensitization with anticancer agents (14)—Perylenequinonoid pigments as new potential photodynamic therapeutic agents: formation of tautomeric semiquinone radicals,J. Photochem. Photobiol. A:Chem, 1992, 69: 191.

    Article  CAS  Google Scholar 

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Project supported by the National Natural Science Foundation of China (Grant No. 39470184).

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Zhang, H., Zhang, Z. Theoretical study of intramolecular proton transfer of perylenequinone. Sc. China Ser. B-Chem. 41, 85–90 (1998). https://doi.org/10.1007/BF02875562

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