The synthesis of some azo dyes formed by s-hydrindacene-1,3,5,7-tetrone with some aromatic amines and the investigation of the effects of concentration, acid, base and substituents upon their UV–visible spectra

In this study s-hydrindacene-1,3,5,7-tetrone (BID: bisindandione) was synthesized from dianhydride of pyromellitic acid, then a new series of azo dyes [2,6-bis(o-, m-, p-substituted phenylazo)-s-hydrindacene-1,3,5,7-tetrones] were obtained by the coupling reaction of BID with some o-, m-, p-substituted (hydroxy, etoxy, nitro, carboxy and methyl) benzendiazonium salts. The effects of subtituents, concentration, acid and base upon the UV–visible spectra of these disperse dyes were investigated.