Structure–properties relationships investigation on the azo dyes derived from benzene sulfonamide intermediates

Several diaminobenzene and aminobenzene intermediates based on sulfonamide and azo dyes derived therefrom were synthesized and characterized by FTIR, MS and 1H NMR. These azo dyes have been used to dye cotton and wool fibre, further their spectroscopic data and application properties were estimated. Especially, it was found that the properties of these derived azo dyes are affected by the sulfonamide substituted bridged groups between the two benzene rings of the corresponding intermediates. In addition, the crystallographic structure of a new type of 1,4-bis-(4-amino-benzenesulfonyl)-piperazine intermediate was determined by X-ray diffraction, which reveals that its molecular configuration is non-planar.