Photoluminescent chiral carbon dots derived from glutamine

The integration of luminescence and chirality in carbon dots (CDs) encourages candidates to explore novel functions and applications of CDs, however, the preparation of chiral CDs is very limited. Herein, we report a hydrothermal method to fabricate chiral CDs by utilizing amino acid enantiomers as the precursors. LGln-CDs or DGln-CDs with uniform size of 3-4 nm show excitation-dependent blue fluorescence in solutions. Circular dichroism measurement confirms the opposite optical rotation of chiral CDs in the region from 200 nm to 300 nm, and the signals can be regulated by concentrations of CDs solution. Time-dependent density functional calculation reveals that polypeptides may exist on the surface of CDs due to the polycondensation of L/DGln at high temperature, and the optical activity of CDs originates from the stacking of neighboring carbonyl groups. The facile synthetic methodology proposed will provide potential opportunities for the preparation and application of chiral and chiroptical CDs-based materials. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

This study presents a hydrothermal method to fabricate chiral CDs using amino acid enantiomers as precursors, resulting in CDs with excitation-dependent blue fluorescence and opposite optical rotation in solutions modulated by concentrations of CDs. Time-dependent density functional calculation suggests the presence of polypeptides on the surface of CDs, contributing to the optical activity originating from the stacking of neighboring carbonyl groups.