Porous organic cages (POCs) are an emerging class of porous molecular materials which self-assembled by discrete, shape-persistent, cage-like molecules and have recently received intensive interest in diverse fields. In this work, a hydroxyl-functionalized homochiral POC was synthesized by [4 + 6] condensation of 2-hydroxy-1,3,5-triformylbenzene with (1 R , 2 R )-diaminocyclohexane and coated on a capillary column for gas chromatography (GC) separations. Forty-one pairs of enantiomers belonging to various classes have been resolved on the column, including alcohols, diols, esters, lactones, halohydrocarbons, ethers, epoxides, ketones and sulfoxides. Compared with β-cyclodextrin derivative-based commercial β-DEX 120 column, previously reported chiral POCs- (CC9 and CC10) based columns, there are 12, 27 and 19 pairs of studied enantiomers cannot be resolved on β-DEX 120 column, CC9 column and CC10 column, respectively. Besides, both separation factors and resolution values of some racemates are higher on this column than those on β-DEX 120 column, CC9 column and CC10 column. The results demonstrate that the column exhibits good chiral recognition complementarity or superior chiral resolution capability to those columns which used for comparison, and the introduction of hydroxyl group enhances hydrogen-bonding interaction to some racemates, leading to better enantioselectivity. The column also shows excellent separation performance toward positional isomers of dichlorobenzene, dibromobenzene, nitrotoluene, chlorotoluene, nitrobromobenzene and nitrochlorobenzene. The retention time and selectivity of analytes have no significant changes after more than 500 injections and 260 °C conditioned for 6 h, showing the good repeatability and thermal stability of the column. This work indicates the promising prospect of POCs for GC separation, especially for the separation of enantiomers and also demonstrates the significance of design and synthesis of more functionalized chiral POCs for GC enantioseparation that broaden the enantiomer separation scope and applicability of POCs-based columns through their chiral recognition complementarities.

中文翻译：

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气相色谱法在同手性多孔有机笼基手性固定相上进行对映体分离

多孔有机笼（POCs）是一类新兴的多孔分子材料，它由离散的、形状持久的、笼状分子自组装，最近在不同领域受到了广泛的关注。在这项工作中，通过 2-羟基-1,3,5-三甲酰基苯与 (1 R , 2 R )-二氨基环己烷的 [4 + 6] 缩合合成了羟基官能化的单手性 POC，并涂覆在毛细管柱上用于气相色谱(GC) 分离。41 对不同类别的对映异构体已在色谱柱上得到分离，包括醇类、二醇类、酯类、内酯类、卤代烃类、醚类、环氧化物类、酮类和亚砜类。与基于 β-环糊精衍生物的商用 β-DEX 120 色谱柱相比，先前报道的基于手性 POCs-（CC9 和 CC10）的色谱柱有 12 个，27 对和 19 对研究的对映异构体分别无法在 β-DEX 120 色谱柱、CC9 色谱柱和 CC10 色谱柱上拆分。此外，部分外消旋物在该色谱柱上的分离因子和分离度值均高于 β-DEX 120 色谱柱、CC9 色谱柱和 CC10 色谱柱。结果表明，该色谱柱与用于比较的色谱柱相比具有良好的手性识别互补性或优越的手性拆分能力，并且羟基的引入增强了与一些外消旋物的氢键相互作用，从而导致更好的对映选择性。该色谱柱对二氯苯、二溴苯、硝基甲苯、氯甲苯、硝基溴苯和硝基氯苯的位置异构体也表现出优异的分离性能。进样 500 次以上、260 °C 老化 6 h 后，分析物的保留时间和选择性均无明显变化，表明该色谱柱具有良好的重复性和热稳定性。这项工作表明了 POCs 在 GC 分离中的广阔前景，尤其是对映体的分离，也证明了设计和合成更多官能化手性 POCs 用于 GC 对映体分离的意义，通过其扩展了基于 POCs 的色谱柱的对映体分离范围和适用性。手性识别互补。