Green and controlled synthesis of copper-based tryptophan flower-like chiral metal-organic framework for enantioselective recognition and volatile organic compound separation.

This study reports the synthesis and application of a flower-like chiral metal-organic framework (CMOF) based on copper ions and tryptophan (Cu(Trp)-CMOF). The Cu(Trp)-CMOF was successfully synthesized at room temperature through a facile method with hexadecyl trimethyl ammonium bromide (CTAB) as a structure-directing agent. The material exhibits a flower-like morphology with hierarchical porosity and well-defined crystallinity in the monoclinic P21/c space group. Comprehensive characterization revealed that different optical configurations ((R)-type, (S)-type, and (RS)-type) could be selectively obtained by controlling the chirality of tryptophan ligands. The synthesized CMOFs demonstrated excellent performance in two key applications: colorimetric recognition of amino acid enantiomers and separation of volatile organic compounds (VOCs). When used as a chromatographic stationary phase, the CMOF significantly enhanced the separation of challenging structural isomers, particularly improving the resolution (RS) of xylene isomers (RS from 1.03 to 2.62) and ethyltoluene isomers (RS from 4.83 to 9.23) compared to conventional columns. This work provides new insights into the design and application of CMOFs for chiral separation and recognition.