Synthesis of Chiral Porous Organic Polymers Through Nucleophilic Substitution for Chiral Separation

A chiral porous organic polymer (cPOP) was synthesized from chiral 1,2-bis(3,4-dichloromaleimide)cyclohexane and 1,3,5-tri(4-aminophenyl)benzene through facile and catalyst-free nucleophilic substitution reactions. The resulting cPOP consisted multistage porous structures with a BET specific surface area of 404 m2/g. It showed a high thermal stability as indicated by thermogravimetric analysis. A series of secondary alcohols were enantioselectively adsorbed by the cPOP to achieve enantiomeric excess (ee) values up to 72%. To be further used for liquid chromatography separation, a one-pot method was designed to attach the cPOP onto silica particles to fabricate the SiO2@cPOP composite with a regular shape and uniform size. The racemic mixture of α-(1-naphthyl)ethanol was successfully separated on a simulated liquid chromatography column with SiO2@cPOP as the stationary phase to give single enantiomers at the forefront and at the end of the elution. The features of good resolution performances, simple operating procedure, and facile synthetic conditions would endow the cPOP with potential applications in practical chiral separation of racemates.