Synthesis of azo dyes prepared from some 2-aminothiophene derivatives with carbocyclic and heterocyclic amines and investigation of their spectroscopic properties

In this study, Four series of azo dyes were synthesized by using some ethyl 2-amino-phenylthiophene carboxylate derivatives as coupling components and coupling them with diazonium salts of various substituted carbocyclic and heterocyclic amines. The structures of the compounds were evaluated by using FT-IR, 1H-NMR and mass spectroscopic techniques. The absorption spectra of these compounds in DMSO, methanol, acetic acid and chloroform were investigated. The solvent, substituent and acid-base effects on the absorption spectra of the dyes were also examined in detail. A linear correlation was observed between the Hammett substituent constants and the absorption maxima of the dyes which are synthesized from carbocyclic amines. It was also determined that substituent effect was not affected by the solvent.