Cyclotriveratrylene–carbazole cage for self-assembly of C60

A novel open-bowl pyramidal compound cyclotriveratrylene–carbazole (CTV–CZ) was designed and synthesized. Its absorption and emission spectroscopic properties in different organic solvents were characterized. Three absorption peaks of CTV–CZ around 235 nm, 260 nm and 290 nm were observed. The fluorescence emission peaks were at about 353 nm and 368 nm using a solution of ∼10−7 M CTV–CZ. The intermolecular interaction between CTV–CZ and fullerene (C60) was studied in detail by UV–vis absorption and fluorescence spectra. CTV–CZ could associate with C60 to form supramolecular complex with 1:1 molar ratio and the binding constant was estimated to be 5.0(6)×104 M−1 by fluorimetry. The formation of inclusion complex for CTV–CZ and C60 was further confirmed by 1H NMR and cyclic voltammetry. The downfield shift of protons of CTV–CZ in its 1H NMR spectrum and the decrease of redox currents on addition of C60 showed that photo induced electron transfer (PET) occurred from the electron donor CTV and CZ units to the electron acceptor C60.