基于密度泛函理论研究锂-冠醚复合物的结构和热力学参数

冠醚对碱金属离子具有高选择性，在锂元素的分离富集上有着广泛的应用。本文基于密度泛函理论（DFT）研究了冠醚环大小、取代基种类、配位原子种类和数量等因素对冠醚空间结构和热力学参数的影响。结果表明，苯并冠醚系列中的苯并-15-冠-5具有更好的配位能力，取代基、配位原子对冠醚的络合能力均有一定影响，因此可通过选择合适的冠醚环，引入供电子基团和含氮杂原子等方法来改善冠醚的分离富集能力。这对冠醚体系分离富集锂元素具有重要的指导意义。

Density Functional Theory Studies of the Structures and Thermodynamic Parameters of Li+-Crown Ether Complexes

Crown ethers have been widely used for lithium separation in practical applications due to their selectivity. In this study, model crown ethers having different cavity sizes, donor atoms and electron donating/ withdrawing substituent groups were systematically designed. These ethers were subsequently used to study the chemical structures and thermodynamic parameters of Li⁺-crown ether complexes, employing density functional theory at the B3LYP/6-311+G(d,p) level. Benzo-15-crown-5 was found to have the ability to strongly coordinate lithium ions. It was determined that the coordination ability of crown ethers for lithium ions can be tuned by varying both the substituent groups and the type and amount of donor atoms. These results should be of significant benefit in developing the practical applications of crown ethers for lithium separation.