Synthesis of i‐Corona[6]arenes for Selective Anion Binding: Interdependent and Synergistic Anion–π and Hydrogen‐Bond Interactions

Abstract

Abstracti‐Corona[3]arene[3]tetrazines were synthesized from the nucleophilic aromatic substitution reaction of resorcinol and its derivatives with 3,6‐dichlorotetrazine in a one‐pot fashion under mild conditions. All of the resulting macrocycles adopted 1,3,5‐alternate conformation irrespective of the nature of the substituents on both upper‐ and lower‐rims. i‐Corona[3]arene[3]tetrazine was found to self‐regulate its macrocyclic conformation and cavity to recognize anions with binding constants spanning from 26 M−1 to 2.2×103 M−1 depending on the structure of the anions. The selective binding resulted from a significant interdependent and synergistic effect between multiple tetrazine π/anion and Caryl–H/anion hydrogen bond interactions. Taking advantage of synergistic effect revealed, a cyanobenzene‐embedded i‐corona[3]arene[3]tetrazine was designedly synthesized and highly selective and very strong affinity toward nitrate with a binding constant of 2.2×105 M−1 was achieved.