Anion‐Dependent Binding‐Mode Changes in meso‐(5,6‐Dichlorobenzimidazole) Picket Calix[4]pyrrole

A deep-cavity calix[4]pyrrole anion receptor bearing 5,6-dichlorobenzimidazole subunits at diametrically opposed meso positions was synthesized and its anion-binding properties were investigated. The synthesized receptor showed higher affinity for fluoride anions than for chloride anions with a high discrimination factor. Significant differences in the solid-state geometries between the fluoride and chloride complexes were observed.