Homochiral Eu3+@MOF Composite for the Enantioselective Detection and Separation of (R/S)-Ornidazole

The development of homochiral materials for the enantioselective detection and separation of chiral drugs is in high demand for the pharmaceutical industry. Herein, an anionic homochiral metal-organic framework (HMOF) with in situ generated [Me2NH2](+) counterions, {[Me2NH2](2)[Zn-2(D-L)(2)(HCO2)(OH)]center dot 5H(2)O}(n) (HMOF-1), was synthesized using a D-camphorate-derived enantiopure dicarboxylate ligand, 4,4'[[(1R,3S)-1,2,2-trimethylcyclopentane-1,3-dicarbonyl]bis(azanediyl)]dibenzoic acid (D-H2L) via a simple solvothermal method. Interestingly, HMOF-1 could be used as a parent framework to encapsulate Eu3+ cations via an ion-exchange process, yielding an Eu3+@ HMOF-1 composite with dualluminescent centers. The obtained Eu3+@HMOF-1 has high chemical stability and good luminescence stability in water. Importantly, Eu3+@HMOF-1 exhibits enhanced enantioselectivity and sensitivity in the detection of an important chiral nitroimidazole antibiotic, (R/S)-ornidazole (ONZ) in comparison to HMOF-1 under the same aqueous conditions. The enantiomeric excess (ee) value of the ONZ enantiomers can be accurately determined by the ratio of dual emission from the ligand and Eu3+. In addition, Eu3+@HMOF-1 shows the enantioselective separation of racemic ONZ enantiomers with an ee value of 86.6%. This work provides a simple strategy for the preparation of Ln(III)-incorporated HMOF composite materials for the simultaneous enantioselective detection and separation of chiral drugs.

Automated summary

This study developed a homochiral metal-organic framework (HMOF) that could be used for the detection and separation of chiral drugs. By encapsulating Eu3+ cations, a dual-luminescent composite material was synthesized with high chemical stability and enantioselectivity. This work provides a simple strategy for the preparation of Ln(III)-incorporated HMOF composite materials for simultaneous enantioselective detection and separation of chiral drugs.