Abstract Separation of molecular isomers, which have similar physical properties, is hardly achieved with conventional separation methods based on phase equilibria. However, using selective inclusion of target molecules into dismantlable molecular framework allows molecular isomers to be effectively separated from one another. For that purpose, we consider the hydrogen-bonded organic framework (HOF), which can undergo solvent-mediated crystallization. Herein, we theoretically elucidated the separation mechanism of the mixture of xylene isomers (i.e., o-, m-, and p-xylene) and ethyl benzene (EB) using guanidinium (G) cation and organosulfonate anion (S) host systems (i.e., 2(G) + 4,4′-biphenyldisulfonate (G2BPDS) and 2(G) + 2,6-naphthalenedisulfonate (G2NDS) GS-host systems). Density functional theory (DFT) calculations were carried out to investigate separation mechanisms in terms of thermodynamics (i.e., formation energy, interaction energies of guest-host and guest-guest, and vacancy formation energy) and kinetics (i.e., surface energy) considering the solvent-mediated crystallization process. We theoretically predicted that G2BPDS system could effectively separate EB from xylene isomers, and G2NDS system could separate each xylene isomer by sequential separation process.

中文翻译：

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基于第一性原理计算的氢键主体骨架二甲苯异构体和乙苯的分离原理

摘要 基于相平衡的常规分离方法很难实现物理性质相似的分子异构体的分离。然而，通过将目标分子选择性地包含在可拆卸的分子框架中，可以有效地将分子异构体彼此分离。为此，我们考虑了氢键有机骨架 (HOF)，它可以进行溶剂介导的结晶。在此，我们从理论上阐明了使用胍 (G) 阳离子和有机磺酸盐阴离子 (S) 主体系统（即，邻二甲苯、间二甲苯和对二甲苯）和乙苯（EB）的混合物的分离机理（即, 2(G) + 4,4'-联苯二磺酸盐 (G2BPDS) 和 2(G) + 2,6-萘二磺酸盐 (G2NDS) GS-宿主系统）。进行密度泛函理论 (DFT) 计算以研究热力学（即形成能、客-主客-客的相互作用能和空位形成能）和动力学（即表面能）方面的分离机制，考虑到溶剂介导的结晶过程。我们从理论上预测 G2BPDS 系统可以有效地将 EB 与二甲苯异构体分离，而 G2NDS 系统可以通过顺序分离过程分离每个二甲苯异构体。