DFT Study on Tautomerism of Gaseous Cytosine
- Received Date: 2004-03-19
- Density Functional Theory, Cytosine, Tautomerism /
Abstract: By comparing the ready experimental results with the calculated results obtained at 7 basis sets and 3 theoretical levels, respectively, for the tautomeric form Cyt1 of cytosine, the relatively accurate B3LYP/6-311+G** theoretical method to study the tautomerism of cytosine was chosen. The ground-state structures of 8 tautomers of cytosine were fully optimized at B3LYP/6-311+G** level, and the tautomerism of 6 relatively stable tautomers of cytosine was studied. The frequency analysis was performed on all the optimized structures. For the groundstate geometries, all the calculated frequencies are real; for the transition-state geometries, there is only one imaginary frequency for each structure. Detailed Intrinsic Reaction Coordination calculations were carried out to guarantee the optimized transition-state structures being connected to the related tautomers. All the energies given include the zero-point energy corrections. The theoretical results can give a reasonable interpretation for the experimental results.
|Citation:||Sun Julong, Yang Guanghui, He Guozhong, Han Keli. DFT Study on Tautomerism of Gaseous Cytosine[J]. Chinese Journal of Chemical Physics , 2005, 18(3): 325-330. doi: 10.1088/1674-0068/18/3/325-330|