| Popis: |
New π-conjugated 1,2-bis(2-aryl-1H-indol-3-yl)ethynes 1a–j having various substituents on the two aryl groups were efficiently synthesized via unusual 5-exo-digonal double isocyanide-acetylene cyclization reactions of 1,4-bis(2-isocyanophenyl)buta-1,3-diyne 3 and aryl Grignard reagents (R-MgBr, R = C6H5 (1a), 4-H3CC6H4 (1b), 2-H3CC6H4 (1c), 3-MeOC6H4 (1d), 3-(CH3)2NC6H4 (1e), 4-F3CC6H4 (1f), 4-FC6H4 (1g), 3-FC6H4 (1h), 4-PhOC6H4 (1i), and 2-Naph (1j)) in 19–85% yields. The UV–vis spectra were rationalized in detail using time-dependent DFT and single point calculations. The fluorescence emission peaks for 1a–j were observed at around 450 nm. Especially for 1f and 1j, those spectra displayed broad emission bands and relatively large Stokes shifts (3977–4503 cm–1), indicating the contribution of an intramolecular charge transfer. The absolute quantum yields (0.50–0.62) of 1a–j were higher than those of parent 8 (0.19) and 2-phenyl-1H-indole (0.11). The electrochemical features for 1a–j were investigated by ... |
