Michal Himl

A urea‐based complexation site represents a building block customarily used in the design of receptors for anion recognition. Here we report a cyclization driven change of complexation preferences, leading to a urea‐based macrocyclic receptor with selectivity for heavier alkali metal cations. Moreover, thorough 1 H and 19 F NMR, HRMS and X‐ray diffraction studies of the complexes revealed an inherent capability of the macrocycle to interact with selected ion pairs.