N-doped carbon quantum dots for the selective detection of OCl− ions, bioimaging, and the production of Fe3O4 nanoparticles utilized in the synthesis of substituted imidazole†

Nitrogen-doped quantum dots (NCQD) were synthesized by solvothermal means using o-phenylenediamine and L-tartaric acid. The resultant NCQD produced a high quantum yield (40.3%) and a vivid green fluorescence. They were about 6 nm in size. The NCQD is useful in HeLa cell bioimaging investigations and is used for the fluorescence detection of OCl⁻ ions. The quantum dots' Limit of Detection (LoD) was discovered to be 40 nM. Additionally, cytotoxicity testing was conducted, and we found out that HeLa cells safely endured up to 6.5 mg ml⁻¹ of NCQD. Furthermore, NCQDs were employed to synthesize Fe₃O₄ nanoparticles, with the quantum dots acting as a reducing and stabilizing agent. The nanoparticles exhibited remarkable catalytic activity towards organic processes due to their size of 11 nm and surface area of 67.360 m² g⁻¹. Excellent yields of tri-substituted imidazole derivatives were produced using Fe₃O₄ nanoparticles as nanocatalysts in a solvent-free method.