339576-55-5Relevant articles and documents
Synthesis and electronic spectroscopy of bromocarbazoles. Direct bromination of N- and C-substituted carbazoles by N-bromosuccinimide or a N-bromosuccinimide/silica gel system
Ponce, Maria B.,Cabrerizo, Franco M.,Bonesi, Sergio M.,Erra-Balsells, Rosa
, p. 1123 - 1139 (2006)
The preparation, isolation and characterization by elemental analysis and 1H-NMR, 13C-NMR, and MS data of the bromo derivatives of N-substituted carbazoles, i.e., of 9-methyl-9H-carbazole (1), 9-phenyl-9H-carbazole (2), 9-benzyl-9H-carbazole (3), 2-methoxy-9-methyl-9H- carbazole (4), and of C-substituted carbazoles, i.e., of 2-(acetyloxy)-9H- carbazole (5) and 3-nitro-9H-carbazole (6), are reported, in part for the first time. As brominating reagents, N-bromosuccinimide (NBS) or NBS/silica gel in CH2Cl2, NBS in AcOH, KBrO3/KBr in EtOH doped with a catalytic amount of H2SO4, or KBrO3/KBr in AcOH were employed, and their uses were compared. Semi-empirical PM3 calculations were performed to predict the reactivity of the N-substituted and C-substituted carbazoles and of their bromo derivatives and found to verify the experimental results. The UV-absorption and fluorescence and phosphorescence emission spectra of the bromocarbazole derivatives in MeCN solution at 298 K and in a solid matrix at 77 K were compared with those of the corresponding carbazoles 1-6. The dynamic properties of the lowest excited singlet and triplet states (τf, τp, φf, and φp) were measured under the same experimental conditions. The intramolecular spin-orbital-coupling effect of the Br-atom and NO2 group on the spectroscopic data, photophysical parameters, and on the photo reactivity were also briefly analyzed.
