A cucurbit uril-based carbon dot for recognizing metal ions and anions in solutions

In this paper, fluorescent nitrogen doped carbon quantum dots (CQDs) were synthesized by a hydrothermal method using cucurbit[6]uril (Q[6]) and mandelic acid (MA). Compared with other carbon quantum dots, cucurbit[6]uril has the advantage that its original rigid macrocyclic skeleton was completely retained during the synthesis process. In addition, the performance of the Q[6]-CQDs were characterized by fluorescence and NMR spectroscopies, then the crystal structure of Q[6]-MA-[CdCl4]2- was determined by the single crystal X-ray crystallography. The Q[6]-CQDs showed good water solubility and stable optical property. Subsequently, using the obtained Q[6]-CQDs, a universal fluorescent probe for detecting and recognizing Fe3+, Ba2+, Al3+, I- and ClO- has been developed based on macrocyclic chemistry. Under ideal conditions, the detection limits were calculated to be 3.89×10-6 M, 2.58×10-5 M, 1.42×10-5 M, 6.84×10-6 M and 1.50×10-5 M.