Direct synthesis of intercalation compounds between a layered double hydroxide and an anionic dye

Intercalation compounds between a layered double hydroxide and an anionic dye were directly synthesized by hydrolysis of mixed solutions of aluminium nitrate, magnesium nitrate, and the anionic dyes (indigo carmine or new coccine). The intercalated indigo carmine anions are possibly arranged with their molecular planes perpendicular to the hydroxide layers. The basal spacings of the new coccine intercalates suggested that the configuration of the new coccine anions in the interlayers changed upon washing. Intercalation of the dyes by anion exchange from layered double hydroxides with NO₃^- or Cl^- as the interlayer anions was also conducted for comparison.