Interaction between an acid dye and bolaform electrolytes containing a benzene ring as a spacer group

Abstract

The binding behaviour of an acid dye, sodium 1-phenylazo-2-hydroxy-6-naphthalenesulphonate, with bolaform electrolytes containing a benzene ring as a spacer group in aqueous solutions was investigated by means of visible absorption spectroscopy. The spectral change of the aqueous dye solutions was strongly dependent on the structure of the terminal groups. The bolaform electrolytes, having various N,N-dimethyl-N-alkylammonium pyridinium terminal groups, formed 1:1 complexes with the dye. The binding constant of the dye with the bolaform electrolyte-containing 4-(N,N-dimethylamino)pyridinium was the largest because of its structure. The thermodynamic parameters for binding were also affected by the structure of the terminal groups. The length of the terminal alkyl chains of the bolaform electrolytes affected the spectral properties. Electrolytes with 10 carbon atoms formed supramolecular complexes (two dyes to one electrolyte). It is concluded that the structure of the bolaform electrolytes is strongly connected with the supramolecular structure of the complexes formed by the dye and the bolaform electrolytes.