Synthesis and properties of fully conjugated macrocycles composed of m -diethynylene-phenylene-bridged two dibenzofuran, dibenzothiophene and carbazole units

Fully conjugated macrocycles 1a−1c composed of m-diethynylene-phenylene-bridged two dibenzofuran, dibenzothiophene and carbazole units were synthesized via Sonogashira cross coupling reactions under high-diluted condition. These conjugated macrocycles were fully characterized by 1H NMR, 13C NMR, FT-IR, Mass spectroscopies and elemental analysis. Photophysical and redox properties of 1a−1c were investigated by means of UV–vis/fluorescence spectroscopies and cyclic voltammetry, respectively, and those features were compared with those of the corresponding linear phenylethynyldibenzoheterols 11a−11c. Furthermore, their structural and electronic insights were studied by theoretical calculations at the B3LYP/cc-pVDZ//B3LYP/6-31G(d) level of theory.