Aryl carbazole-based macrocycles: Synthesis, their remarkably stable radical cations and host-guest complexation with fullerenes

A series of fully conjugated macrocycles Mn (n = 4-7) consisting of N-(3,5-di-Tert-butyl-4-methoxyphenyl) substituted carbazole (Cz-Ar) were successfully synthesized. The aryl carbazole and macrocycle M4 can be readily oxidized and the corresponding radical cation species were found to be highly stable. Moreover, macrocycle M5 was found to form 1 : 1 stoichiometric complexes with fullerenes C60 and C70 with association constants as high as (8.38 ± 0.33) × 104 M-1 and (7.64 ± 0.26) × 104 M-1, respectively.