Surface-up click access to allylimidazolium bridged cyclodextrin dimer phase for efficient enantioseparation

Area of Science:

• Analytical Chemistry
• Chromatography
• Supramolecular Chemistry

Background:

• Chiral stationary phases (CSPs) are crucial for enantioseparation in chromatography.
• Bridged cyclodextrin CSPs offer unique chiral recognition mechanisms.
• Developing novel CSPs with enhanced enantioselectivity remains a key challenge.

Purpose of the Study:

• To synthesize and characterize a novel allylimidazolium-bridged bis(β-cyclodextrin) CSP.
• To evaluate the chiral chromatographic performance of the new CSP for various racemic analytes.
• To compare its enantioseparation ability with existing CSPs.

Main Methods:

• Surface-up thiol-ene click chemistry for CSP fabrication.
• Characterization using FTIR, ¹³C NMR, TGA, and elemental analysis.
• Reversed-phase high-performance liquid chromatography (RP-HPLC) for enantioseparation.
• Molecular docking for interaction analysis.

Main Results:

• Successful synthesis of allylimidazolium-bridged bis(β-cyclodextrin) CSP on a silica surface.
• Demonstrated enhanced chiral recognition and enantioseparation for 35 racemic analytes.
• Achieved complete separation of Ar-Phs and dansyl-amino acids with high resolution.
• Outperformed other reported bridged cyclodextrin CSPs in enantioselectivity.

Conclusions:

• The novel CSP exhibits superior chiral recognition due to abundant hydrogen bonding, electrostatic interactions, and synergistic inclusion.
• The allylimidazolium bridge and bis(β-cyclodextrin) structure contribute to enhanced enantioseparation.
• This CSP represents a promising advancement for chiral separation technologies.