| Yazarlar |
| Özet |
| Motivation. The interaction of alkali metal with thymine is an interesting target of studies in connection with bioinorganic chemistry and biological chemistry of toxicity and carcinogenicity. We studied interactions of one of the oxo groups of thymine and its tautomers with alkali metals (Li, Na, K, Rb and Cs) by ab initio calculations. The stability of these species has been studied in gas and solution phases. Characterization of intermolecular (C= O) and intramolecular (C--N) bonds has been studied with the NBO method and, the interactions that cause the strongest stabilization have been studied, as well. The stability of metalated thymine and its tautomers has been studied thermochemically. The present study reports the quantum chemistry analysis of the metal--assisted tautomerization.Method. Ab initio and DFT methods at the HF and B3LYP levels of theory were used. Results. Interactions of alkali metals with oxo group of thymine and its tautomers stabilize rare tautomers compared to the major form. Investigation of interactions in solution phase shows that with increasing dielectric constants of solvent, the tautomers are stabilizing compared to the major form. Thermochemical analysis shows that the stability of metalated thymine is more for less electropositive metals. These results show that basicity of metalated thymine has been increased. NBO calculations show that in metalated thymine (1, metalated),(5, metalated) the N2 and N4 lone pair is seen to be the lowest occupancy and highest energy Lewis NBO and to be primarily delocalized into antibonds the vicinal π* C3--O3 and π* C1--O1 NBO, respectively. In other species lowest occupancy ... |
| Anahtar Kelimeler |
| Makale Türü | Özgün Makale |
| Makale Alt Türü | Uluslararası alan indekslerindeki dergilerde yayımlanan tam makale |
| Dergi Adı | Internet Electronic Journal of Molecular Design |
| Dergi Tarandığı Indeksler | |
| Makale Dili | İngilizce |
| Basım Tarihi | 01-2003 |
| Cilt No | 2 |
| Sayfalar | 741 / 756 |
