An Effective Hg²⁺‐Selective Fluorescent Chemosensor Based on a Calix[4]arene Bearing Four Dansyl Amides

Abstract

Abstract A new calix[4]arene‐based fluorescent chemosensor bearing four dansyl amides on the upper rim ( 1 ) was conveniently synthesized, which showed high sensitivity and selectivity toward Hg 2+ over a wide range of metal ions in 50% aqueous acetonitrile. The complexation of Hg 2+ ion induced a strong fluorescence quenching of 1 due to a well‐defined electron transfer process from the dansyl group(s) to the metal center. Compared with compounds 2 and 3 , tetradansyl amide substituted calix[4]arene 1 showed a preorganized and coordinated complexing site for metal ions. Moreover, the detection limit for Hg 2+ was found to be 3.41×10 −6 mol·L −1 , which might make 1 a potentially practical Hg 2+ ‐selective fluorescent sensor in aqueous system.