Shape persistence delivers lock-and-key chloride binding in triazolophanes

Triazolophanes have recently surfaced as a new class of shape-persistent macrocycles that bind anions. Bearing only triazole- and phenyl-derived CH hydrogen bond donors, these receptors have shown extraordinary Cl − binding strengths (>10 6 M −1 , CH 2 Cl 2 ). The attributes of the triazolophane that are responsible are presented herein alongside recent literature accounts that have utilized similar strategies in new and exciting supramolecular systems. This review describes how triazolophanes leverage the structural pre-organization characteristic of spherands to take advantage of non-traditional hydrogen bonds originating from extrinsic CH donors. This feature article highlights how triazolophanes combine the shape-persistence of spherands with polarized CH hydrogen bonds to instill high chloride affinities and selectivities.