Synthesis of new anthracene‐substituted calix[4]triazacrown‐5 as highly sensitive fluorescent chemosensor and extractant against hazardous dichromate anion

A new fluorogenic anthracene functionalized calix[4]triazacrown‐5 (Ant‐AzClx) was successfully synthesized using a simple Schiff’s base reaction. The 1H‐NMR, 13C‐NMR, ESI‐MS, and elemental analysis techniques were performed to characterize its structure. Excited at 370 nm, Ant‐AzClx reveals excimer emission at 418 nm. Therefore, its anion binding properties were investigated against F−, HCO3−, H2PO4−, NO3−, Cr2O72−, and SO42− ions. When hazardous dichromate anion was introduced into medium, the fluorescence intensity of Ant‐AzClx was markedly quenched. The binding constant, stoichiometry, the detection limits and Stern–Volmer equation for the complex formed between Ant‐AzClx and Cr2O72− ion were determined. Furthermore, the 1H‐NMR technique was also performed to assess the mechanism of the complex (Ant‐AzClx@Cr2O72−). Apart from its excellent fluorescent chemosensor properties for selective and sensitive recognition of Cr2O72− ion, Ant‐AzClx was used as an efficient extractant towards dichromate anion. The extraction results indicated that Ant‐AzClx exhibited high extraction capability, leading to it being a promising extractant for the removal of dichromate anions from water. A new calixarene‐based chemosensor has been developed for selective and sensitive recognition of Cr2O72− ions. The results showed that the calixarene‐based sensor is capable of detecting Cr2O72− ions with very low detection limit 0.65 μM. Apart from sensor properties, this new calixarene derivative is capable of removing dichromate anions from water.