Asymmetric catalytic synthesis of chiral covalent organic framework composite (S)-DTP-COF@SiO 2 for HPLC enantioseparations by normal-phase and reversed-phase chromatographic modes.

A novel CCOF core-shell composite material (S)-DTP-COF@SiO ₂ was prepared via asymmetric catalytic and in situ growth strategy. The prepared (S)-DTP-COF@SiO ₂ was utilized as separation medium for HPLC enantioseparation using normal-phase and reversed-phase chromatographic modes, which displays excellent chiral separation performance for alcohols, esters, ketones, and epoxides, etc. Compared with chiral commercial chromatographic columns (Chiralpak AD-H and Chiralcel OD-H columns) and some previously reported chiral CCOF@SiO ₂ (CC-MP CCTF@SiO ₂ and MDI-β-CD-modified COF@SiO ₂ )-packed columns, there are 4, 3, 13, and 15 tested racemic compounds that could not be resolved on the Chiralpak AD-H column, Chiralcel OD-H column, CC-MP CCTF@SiO ₂ column, and MDI-β-CD-modified COF@SiO ₂ column, respectively, which indicates that the resolution effect of (S)-DTP-COF@SiO ₂ -packed column can be complementary to the other ones. The effects of the analyte mass, column temperature, and mobile phase composition on the enantiomeric separation were investigated. The chiral column exhibits good reproducibility after multiple consecutive injections. The RSDs (n = 5) of the peak area and retention time were less than 1.5% for repetitive separation of 2-methoxy-2-phenylethanol and 1-phenyl-1-pentanol. The chiral core-shell composite (S)-DTP-COF@SiO ₂ exhibited good enantiomeric separation performance, which not only demonstrates its potential as a novel CSP material in HPLC but also expands the range of applications for chiral COFs.
(© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)