ChemInform Abstract: Synthesis and Properties of Hydroxystyrylquinolines.

ChemInform Abstract

The title compounds (III) and (V) are prepared. The VIS spectra of these dyes with an arylazo group are examined and compared to those of analogous dyes with a nitro group instead of the phenylazo group. In comparison to the nitro analogues, which were examined earlier, the dyes (III) and (V) display two maxima of absorption. This is believed to be the result of a mutual influence of the two chromophores, i.e. the polymethine and the azo chromophores, which causes a hypsochromic shift of the short-wave absorption band and a bathochromic shift of the long-wave absorption band. Furthermore, the introduction of an arylazo group into the styryl moiety enhances the acidic properties of the compounds. The pKa value is found to be about 1.8 units lower as compared to analogues without an arylazogroup.