Pillarnarenes (n = 5–10), novel macrocycles, are gaining prominence in supramolecular studies owing to their distinctive three-dimensional architecture featuring a π-electron-rich cavity and have emerged as a key synthetic macrocyclic host in research. Extended pillarnarenes (EpnAs) notably feature sizable internal voids, adaptable structures, versatile cavity shapes, and ease of synthesis. This work presents the first example of imidazolium ionic liquid-functionalized EpnAs (BpP6A-C10-IM-C8NTf2) as a gas chromatography stationary phase. The BpP6A-C10-IM-C8NTf2 column was prepared by the static method, exhibiting medium polarity and high column efficiency (4660 plates/m, k = 2.29). The separation performance of the prepared column was evaluated for analytes, including a mixture of 22 analytes, more than 12 positional isomers, and 8 cis-/trans-isomers. Furthermore, the chromatograms of the challenging isomers of bromonitrobenzenes, chloronitrobenzenes, bromobenzaldehydes, toluidines, and dimethylanilines on the BpP6A-C10-IM-C8NTf2 column were compared with those on the BpP6A-C10 column and commercial HP-5 and HP-35 columns. The BpP6A-C10-IM-C8NTf2 column also showed high selectivity for biphenyl isomers, including methylbiphenyls, iodobiphenyls, and bromobiphenyls.
Qi et al. (2026) studied this question.