Synthesis, structure, and properties of O6 -Corona[3]arene[3]tetrazines.

O6 -Corona[3]arene[3]tetraazines, a new class of macrocyclic compounds, were synthesized efficiently in a one-pot reaction from the nucleophilic aromatic substitution reaction between 1,4-dihydroxybenzene derivatives and 3,6-dichlorotetrazine in warm acetonitrile. In the crystalline structure, the resulting macrocycles adopt highly symmetric structures of a regular hexagonal cavity with all bridging oxygen atoms and tetrazine rings located on the same plane with phenylene units orthogonally orientated. The constitutional aromatic rings are able to rotate around the macrocyclic annulus, depending on the steric effect of the substituents and temperature, in solution. The electron-deficient nature revealed by cyclic voltammetry, differential pulse voltammetry, and characteristic absorbances at a visible region show the O6 -corona[3]arene[3]tetrazines to be suitable macrocyclic receptors for electron-rich guests.