Synthesis and Structure of Corona[6](het)arenes Containing Mixed Bridge Units

A one-pot nucleophilic aromatic substitution reaction of 3,6-dichlorotetrazine with various diphenols and dibenzenethiols produced corona[4]­arene[2]­tetrazines that contain mixed oxygen, sulfide, methylene, and sulfone linkages. Macrocyclic ring transformations employing an inverse-electron-demand Diels–Alder reaction of tetrazine moieties with enamines and the subsequent sulfide oxidation reaction afforded diverse corona[4]­arene[2]­pyridazines. The acquired corona[6]­arenes adopted three types of conformational structures in the crystalline state.