Structurally Diversified Calix[3]phenoxazines: Synthesis, Solid-State Conformational Investigation, and Host-Guest Chemistry.

A new type of phenoxazine-based macrocyclic arene, calix[ n ]phenoxazines, are reported. Structurally diversified calix[3]phenoxazines with different substitutes on nitrogen atoms and methylene bridges are synthesized with a yield of 30%-70%. Single crystal structure and density function theory calculation show calix[3]phenoxazines possess electron-rich cavities, which can selectively encapsulate suitable electron-deficient guests through multiple noncovalent interactions.