Top-Down Exfoliation of Ultrathin Chiral 2D Nanosheets for High-Resolution Gas Chromatography

Compared with bulk crystal materials that have limitations such as high mass transfer resistance and insufficient exposure of surface action sites, the development of ultrathin two dimensional nanosheets is more attractive. Developing chiral stationary phases with both structural stability and high enantioselectivity remains a key challenge in this field. This study reported a chiral ionic organic single-crystal (BPDS-PBIM), which was constructed by the ionic self-assembly of 4,4'-biphenyldisulfonic acid (BPDS) and chiral ionic liquid (PBIM). Its distinct supramolecular environment with multiple chiral centers and unique molecular packing pattern was confirmed by single-crystal X-ray diffraction (SC-XRD, space group P2₁). Experiments showed that the stationary phase of 2D nanosheets, prepared by exfoliating BPDS-PBIM, exhibited exceptional separation performance for complex pharmaceutical molecules (e.g., ibuprofen, ketoprofen, flurbiprofen, fenoprofen, mexiletine hydrochloride) and chiral compounds with different polarity. This work not only demonstrates the powerful potential of BPDS-PBIM as a chiral stationary phase but also suggests its broad application prospects in fields such as pharmaceutical analysis, flavor and fragrance quality control, and chemical reaction monitoring.