Synthesis and characterization of a sensitive and selective Fe^(3+) fluorescent sensor based on novel sulfonated calix[4]arene-based host-guest complex

A novel fluorescent sensor was prepared from sulfonated calix[4]arene(SC4A)by the host-guest com-plexation method using the fluorescent dye rhodamine B(RB)as a structure-directing agent.The crystal structure of the host-guest complex(RB@(SC4A)_(3))was confirmed by X-ray diffraction studies while its performance and sensing mechanism for metal ion pollutants were characterized using fluorescence and nuclear magnetic resonance spectroscopies.The results showed that RB@(SC4A)_(3) had a triangular branch structure resulting from host-guest mediation of the interactions between the three SC4A host molecules and the three terminal groups of the guest molecule RB.The host-guest complex exhibited sensitive and selective sensing towards Fe^(3+)ions via a fluorescence quenching mechanism.The results indicated that RB@(SC4A)_(3) could be a promising sensitive and selective fluorescent sensor for metal ion pollutants mon-itoring.It also provided new insights into the synthesis of calixarene-based host-guest complex.