6-氮杂胞嘧啶与甲酸氢键复合物稳定性的理论研究

采用密度泛函B3LYP方法，在6-31G（d，P）基组水平上对6-Aza与trans—HCOOH、cis．HCOOH及HC00-形成氢键复合物进行研究，获得了20种稳定的氢键复合物，并获得了复合物的总能量、相对能和零点能。计算结果表明，6-Aza与trans—HCOOH、cis—HCOOH中H和O相连形成复合物的热力学稳定性为：M8〉Ml〉M3〉M2〉M9〉M6〉M7〉M12〉M11〉M15-M16〉M10〉M5〉M13〉M14，其中6-Aza氨酮式和甲酸反式结构中的醇式结合形成复合物M8的稳定性最高。6-Aza与HC00-反应的热力学稳定性顺序：M20〉M19〉M17〉M18。

Theoretical study of the stability of the intermolecular H-bonds betwween 6-azacytosine arrd formic acid derivatives

The stabilities of 6-azacytosine and formic acid derivatives were investigated by B3LYP-DFT with 6-31 G （d, p） basis set and 20 complexes were located. The total energy, relative energy, zero-point en- ergy were also obtained. The results showed that the thermodynamic stabilities of 6-azacytosine-HCOOH is M8 〉MI〉M3 〉M2〉M9〉M6〉M7 〉M12〉Mll 〉M15≈M16〉M10〉M5 〉M13 〉M14. 6-Aza-trans- HCOOH to exit as amino-keto form M8 are the predominant isomer in the gas phase. The thermodynamic stabilities of 6-azacytosine-HCO0 - is M20 〉 M19 〉 M17 〉 M18.