Scheme 1. Synthetic route to CNCz-BNCz. Reaction conditions: (a) (i) tert-butylcarbazole, NaH, N,N-dimethylformamide, rt, 0.5 h; (ii) 1,4-dibromotetrafluorobenzene, 140 °C, 12 h. (b) (i) n-BuLi, toluene, −60 °C, 1 h; (ii) BBr3, −40 °C to 0 °C, 1 h; (iii) EtN(i-Pr)2, 120 °C, 8 h. (c) (i) n-BuLi, tetrahydrofuran, −78 °C, 1 h; (ii) dimethylmalononitrile (DMMN), −78 °C to rt, overnight. Inset: the crystal structure of CNCz-BNCz.
