Ion sensing with a calix[4]arene bifunctional receptor with thiosemicarbazone moieties and naphthalene chromophore

Abstract

Abstract We have developed a chemosensor using calix[4]arene, which features a thiosemicarbazone binding unit and a naphthalene chromogenic group. Our objective was to understand the intricate binding affinity of these chemosensors towards a diverse range of anions and cations using UV-Visible, HNMR and IR spectroscopic techniques. We show that the chemosensor forms complexes with Ag(I), Cu (II), CN− and F− ions. To understand the complexation behavior, our analysis provides information on the interaction patterns between the receptors and the ions. The sulfur and imine nitrogen on the thiosemicarbazone substituent are vital sites of engagement for cation ions, as evidenced by the observed changes in IR. Studies with anions in HNMR indicate the participation of the thiosemicarbazone hydrogens in the interaction. The interactions that take place during complex formation lead to changes in the color of the solution or solid complex. Our study improves the understanding of molecular recognition in this chemosensor, emphasizing its potential for ion- selective detection.