Synthesis and anion binding properties of 1,8-disulfonamidocarbazole dipyrromethane Schiff-base macrocycle & its amine analogue

AbstractA novel 1,8-disulfonamidocarbazole-dipyrromethane Schiff-base macrocycle (1) and its amine analogue (2) were designed and synthesised, and their anion binding properties were studied via UV–vis and 1H NMR titration spectra. The obtained results showed that a small change in the macrocyclic structure (by reducing imines into the corresponding amines) produced a remarkable impact on its binding affinity and selectivity for anions. For example, macrocycle 1 displayed a 7.9:1 F−/H2PO4− selectivity; however, its amine analogue 2 showed a 78.5:1 F−/H2PO4− selectivity.Keywords: Sulfonamidocarbazoledipyrromethanemacrocyclic receptoranion recognition