LiI-水-尿嘧啶复合物阴离子的几何结构和电子能级研究  

Study of the structures and energetics of LiI-water-uracil anionic complexes

作　　者：李仁忠 徐晓阳 黄健 LI Renzhong;XU Xiaoyang;HUANG Jian(School of Environmental and Chemical Engineering,Xi’an Polytechnic University,Xi’an 710048,China)

机构地区：[1]西安工程大学环境与化学工程学院,陕西西安710048

出　　处：《西安工程大学学报》2022年第6期60-68,共9页Journal of Xi’an Polytechnic University

基　　金：陕西省自然科学基础研究计划项目(2019JM-292);西安工程大学大学生创新训练计划项目(S202110709065)。

摘　　要：针对金属离子与碱基的相互作用中未考虑阴离子效应及阴-阳离子关联机制的问题,使用密度泛函理论研究LiI^(-)水-尿嘧啶复合物阴离子的几何结构和电子能级。通过约化密度梯度(RDG)、分子中的原子法(AIM)及能量分解分析(EDA)等方法研究LiI^(-)水-尿嘧啶的相互作用,并对其进行电荷分析。结果表明:当第1个水分子参与作用时,LiI单元的Li^(+)通过静电相互作用直接与尿嘧啶的O4位点结合,水分子更容易分布在尿嘧啶周围;随着水分子数目的增多,水分子主要分布在尿嘧啶的O2位点至O4位点一侧,通过静电作用与尿嘧啶、Li^(+)和I^(-)发生相互作用,Li^(+)与I^(-)相互分离并以溶剂隔离离子对(solvent separatedion pair, SSIP)结构形式存在。相互作用分析表明,Li^(+)与尿嘧啶间的相互作用随着水分子数目的增多而减弱。电荷分析表明,过剩电荷主要分布在尿嘧啶的O2、O4和C6位点上。Anion effect and anion-cation correlation mechanism are generally not considered in the interaction between metal ions and bases.Thus the geometric structure and electronic structure of the LiI^(-)water-uracil anionic complexes were studied by density functional calculation. The interaction of LiI^(-)water-uracil was analyzed from the perspective of reduced density gradient(RDG), atom in molecule(AIM) and energy decomposition analysis(EDA), with charge analysis carried out. The results show that when the first water molecule was involved, Li^(+)of LiI unit was directly bound to the O4 site of uracil through electrostatic interaction, and water molecules were easier to be distributed around uracil. With the increase of the number of water molecules, water molecules were mainly distributed from the O2 site to the O4 site of uracil, and interact with uracil, Li^(+)and I^(-)through electrostatic interaction. Li^(+)and I^(-)were separated from each other and exist in the form of solvate separated ion pair(SSIP) structure. Interaction analysis shows that the interaction between Li^(+)and uracil would be weakened with the increase of the number of water molecules. Charge analysis shows that the excess electron was mainly distributed at O2, O4 and C6 sites of uracil.

关 键 词：尿嘧啶 LII 约化密度梯度法 能量分解分析 水团簇 

分 类 号：O641.3[理学—物理化学]