Abstract
When the thymine base is oxidized, the resulting cation may deprotonate reversibly at N3, or irreversibly at >C5-CH3. In all thymine derivatives studied so far in the solid state, there is always a significant concentration of a radical formed by net H-abstraction from the >C5-CH3. DFT calculations on this allyl-like radical are in good agreement with the experimental results for both the isotropic and anisotropic hyperfine couplings. There is a tendency for the thymine cation to deprotonate at N3 in solution. Calculations on the N3 deprotonated thymine cation yield two structures, one planar radical with an unusually large N1-C2 bond length, and one nonplanar radical with the N3 more than 25° out of the molecular plane. Calculations show that the structure with the lowest energy is the allyl-like radical.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
Close, D. M. Radiat. Res. 1993, 135, 1.
Steenken, S. Free Radic. Res. Commun. 1992, 16, 349.
Sevilla, M. D. J. Phys. Chem. 1971, 75, 626.
Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery, J. A. Jr.; Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam, M.; Daniels, J. M.; Kudin, A. D.; Strain, K. N.; Farkas, M. C.; Tomasi, O.; Barone, J.; Cossi, V.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford, S.; Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Cioslowski, J.; Ortiz, J. V.; Baboul, A. G.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Gonzalez, C.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Andres, J. L.; Gonzalez, C.; Head-Gordon, M.; Replogle, E. S.; Pople, J. A.; Gaussian, Inc., Pittsburgh PA, 1998.
Geimer, J.; Brede, O.; Beckert, D. Chem. Phys. Lett. 1997, 276, 411.
Geimer, J.; Beckert, D. J. Phys. Chem. 1999, 103, 3991.
Naumov, S.; Barthel, A.; Reinhold, J.; Dietz, F.; Geimer, J.; Beckert, D. Phys. Chem. Chem. Phys. 2000, 2, 4207.
Wong, M. W.; Frisch, M. J.; Wiberg, K. B. J. Am. Chem. Soc. 1991, 113, 4776.
Hush, N. S.; Cheung, S. A. Chem. Phys. Lett. 1975, 24, 11.
Gatzweiler, W., Huttermann, J.; Rupprecht, A. Radiat. Res. 1994, 138, 151.
Heller, A. Faraday Discuss. 2000, 116, 1.
Hole, E. O.; Sagstuen, E.; Nelson, W. H.; Close, D. M. J. Phys. Chem. 1991, 95, 1494.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Close, D., Forde, G., Gorb, L. et al. Model Calculations of Radiation-Induced Damage in Thymine Derivatives. Structural Chemistry 14, 451–454 (2003). https://doi.org/10.1023/B:STUC.0000004489.70088.ed
Issue Date:
DOI: https://doi.org/10.1023/B:STUC.0000004489.70088.ed