“…Anion recognition in solution though is an arduous task, due to issues related to their large size, that requires suitable host cavities for inclusion, and other crucial properties such as multiple protonation equilibria, diverse geometries (spherical, linear, trigonal, tetrahedral, octahedral), high solvation energies. Especially in water, recognition of anions by synthetic receptors is a real challenge, since water can hydrate the receptor and the substrate through strong hydrogen bonds, competing for the hydrogen bonding sites of the receptor [6–9] . Nevertheless, sensing of anions is highly desirable, not only due to the crucial role anions play in life processes, but also because they are becoming a considerable source of pollution in wastewater.…”