Isostructural chiral metal–organic frameworks for enantioselective luminescence sensing of 1-phenyl-1,2-ethanediol

Abstract

We report the synthesis of isostructural chiral metal–organic frameworks (CMOFs), Zn–L–(Et)₂, Zn–L–Me and Zn–L, based on Zn₂ paddle-wheel secondary building units and three 1,1′-bi-2-naphthol (BINOL)-derived tetrabenzoate ligands [L–(Et)₂, L–Me, and L], featuring different alkyl substituents at the 2,2′-hydroxyl positions. These CMOFs were evaluated as luminescent sensors for the enantiomers of 1-phenyl-1,2-ethanediol (PE). All three CMOF sensors exhibited selective quenching of S-PE over R-PE, with significantly higher quenching efficiencies than their corresponding free ligands. The presence of hydroxyl groups induced nonlinear quenching behaviour toward S-PE, further enhancing quenching efficiency. Notably, Zn–L–Me and Zn–L showed exponential quenching responses as a function of enantiomeric excess (ee) at a PE concentration of 1.6 mM.