Chiral carbon dots from glucose by room temperature alkali-assisted synthesis for electrocatalytic oxidation of tryptophan enantiomers

Chiral catalysis is one of the most direct and effective approach to obtain pure optical enantiomers. Chiral carbon dots (CDs) as carbon-based chiral catalysts show great potential in chiral catalysis. Herein, we report a facile one step base-catalyzed aldol condensation to fabricate the chiral CDs from glucose at ambient temperature and pressure. The formation of chiral CDs involves the processes of isomerization and aldol condensation. These chiral CDs have been demonstrated that they have selective capacity for electrocatalytic oxidization of tryptophan enantiomers. L type of CDs (LCDs) is more likely to catalyze L-tryptophan (Trp) than D-Trp with the selective factor (I_L/I_D) of 1.60, whereas the D type of CDs (DCDs) tends to catalyze D-Trp (I_L/I_D: 0.63). Theoretical calculations combined with various contrast experiments (temperature and pH) demonstrate that the selectively electrocatalytic capacity of chiral CDs toward Trp isomers is due to the different hydrogen-bond interactions between chiral CDs and Trp.