Corral[n]Bicarbazoles: Redox-Active Chiral Macrocycles for Air-Stable Radical Cations Formation and Guest...

Macrocyclic compounds are pivotal in both supramolecular chemistry and materials science, as their preorganized cavities enable selective molecular recognition, while their cyclic frameworks facilitate electronic and spatial coupling of monomeric units to yield advanced optoelectronic and magnetic properties. However, macrocycles that combine exceptional host-guest recognition with these properties remain rare and challenging to design. Herein, we report the synthesis of three pairs of enantiopure, redox-active, conjugated macrocycles, termed corral[n]bicarbazole, employing axially chiral 4,4'-bicarbazole units. These macrocycles display strong blue emission (quantum yields up to 78% in THF) and pronounced circularly polarized luminescence (|g_lum| up to 10^-3). Notably, controlled oxidation of corral[n]bicarbazoles generates their mono- and polyradical cations with exceptional air stability (half-lives up to five days) and intriguing magnetic properties. The electron-rich deep-cavity of corral[4]bicarbazole confers strong hosting ability (K_a = 10⁴-10⁵ M^-1) toward cationic guests, facilitating redox-responsive guest capture/release. By integrating a chiroptical, redox-active backbone with a switchable recognition cavity, corral[n]bicarbazoles offer a versatile platform for advancing interdisciplinary innovation, with potential applications in optoelectronics, spintronics, and smart supramolecular materials.