The1H and13C NMR spectra of 9-vinylcarbazole and its 3-chloro, 3,6-dichloro, and 3-nitro derivatives were recorded and studied. It is shown that electron-acceptor substituents reduce the shielding of the β-carbon atom and the trans proton of the vinyl group. A good linear correlation between the chemical shifts of these nuclei and the Hammett σpara - constants with the ρ values (3.78 for13Cβ and 0.28 for1Htrans) is observed. It was established by comparison of the results with the1H and13C NMR spectral parameters for some of the vinyl compounds that the degree of conjugation of the p electrons of nitrogen with the π electrons of the double bond in 9-vinylcarbazoles is lower than in simple vinyl and vinyl phenyl ethers and vinyl acetate.
ASJC Scopus subject areas
- Organic Chemistry