Porous organic cage for enantiomeric fluorescence recognition of amino acid and hydroxy acid

Abstract

A new method based on the enantioselective recognition of porous organic cages CC3‐R was established for the first time. Porous organic cages are widely used for separation, adsorption and host–guest interaction sensing, but are rarely used for fluorescence sensing. Based on the inherent chiral environment of CC3‐R and the inherent fluorescence properties of the organic ligands constituting the cage, when different chiral monomers diffuse into the cage, different effects occur to produce changes in fluorescence. We found for the first time that the fluorescence of CC3‐R can be enhanced and quenched by tyrosine and mandelic acid, respectively, and that different chiral monomers are enhanced or quenched differently at the same concentration. Unlike the chiral recognition of other composite luminescent materials, the chiral porous organic cage not only utilizes its own host–guest effect for chiral recognition, but also utilizes the organic ligands constituting the cage for luminescence recognition. This work provides an alternative method to accomplish chiral recognition other than chromatography, that is using porous organic cages (POC), but it can show the advantages of simplicity, low cost and high sensitivity. We believe this work could provide valuable thoughts in the exploration of POC in chiral recognition as new FL probes for the future.

′Ab Ovo′ Chiral Phases and Chiral Reagents for Liquid Chromatographic Separation and Isolation of Enantiomers

“…Raman and surface enhanced Raman (SERS) spectroscopy proved the formation of host‐guest intermolecular complexes between propranolol enantiomers and α, β, γ CDs [147] . The alternative methods including use of chiral columns, electro migration techniques, porous organic cages, [148] chiroptical sensing with a single arylisocyanate probe [149] etc, have high equipment and running costs and other limitations to be used routinely. The final choice of method, however, would depend upon the situation, nature and chemical structure of the analyte and the ease of availability of laboratory facilities.…”