Enantioselective Recognition Driven Photocatalytic Degradation of d-Tryptophan Enantiomers Based on l-Cysteine-Modified β-Cyclodextrin.

The enantioselective recognition and separation of racemic tryptophan are of significant importance in the fields of medicine, pharmaceutics, and biochemistry. However, conventional methods are costly, energy intensive, and environmentally unfriendly. In this case, l-Cys with amino (-NH) and sulfhydryl (-SH) groups was chosen to modify β-CD with a chiral cavity to achieve self-assembly via hydrogen bonding, which not only serves as an electrochemical chiral sensor with enhanced chiral sites at the sensing interface but also achieves a higher enantioselectivity for d-tryptophan enantiomers through hydrogen bonding between the host and guest. Moreover, the d-tryptophan enantiomers were subsequently degraded under catalytic conditions simulating visible light, which was a new approach to introduce chiral properties in photocatalysis without organic synthesis. The use of inclusion-complex formation with β-CD combined with simple electrochemical technology and photocatalytic degradation techniques to efficiently and rapidly identify and degrade harmful d-type amino acid enantiomers offers new avenues, which would have great potential in future studies.