This study investigates the electronic structure of natural DNA nucleosides and their 2’-difoluoro analogues to assess the possible substitution effects of two hydrogen atoms with fluorine ones in the positions of sugar moiety. Gemcitabine representing an analogue with specific features was utilized in this study. To conduct proper calculations, DFT method at the B3LYP/6-31+G* level was accordingly used. In terms of conformational characteristics of gemcitabine and other analogues, full geometry optimizations, atomic charges, dipole moments, NBO, and HOMO & LUMO were duly made. PROSIT was also used to calculate the pseudorotational parameters of gemcitabine and the DNA analogues .The outcome proved that all the 2-difoluoro DNA nucleosides have slight differences in geometrical parameters with natural nucleosides.

这项研究调查了天然DNA核苷及其2'-difoluoro类似物的电子结构，以评估两个氢原子在糖部分位置上可能被氟取代的可能。吉西他滨代表具有特定特征的类似物在本研究中使用。为了进行正确的计算，相应地使用了B3LYP / 6-31 + G *级别的DFT方法。根据吉西他滨和其他类似物的构象特征，进行了完整的几何优化，原子电荷，偶极矩，NBO以及HOMO和LUMO。PROSIT还用于计算吉西他滨及其DNA类似物的假旋转参数。结果证明，所有2-difoluoro DNA核苷的几何参数与天然核苷均略有不同。