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

Abstract

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.

Keywords

• uracil
• lii
• reduced density gradient
• energy decomposition analysis
• water clusters