Azo-Dye Intercalated Ldhs With Supramolecular Structures

Based on host-guest supramolecular intercalated structures of layered double hydroxides (LDHs), azo-dyes have been intercalated into LDHs with different host layers, and the intercalated compounds perform good photo and thermal stabilities. Combing of characterization of XRD, FT-IR, TG/DTA, DS/UV-vis and ICP, crystal structures and photo and thermal stabilities of guest molecules, intercalation precursors and intercalated products have been investigated respectively.Series of LDHs containing nickel with different host layers have been synthesized by separate nucleation and aging steps. Crystal structures of NiAl-LDHs and NiFe-LDHs are more ordered than those of NiCr-LDHs. By comparison with LDHs containing Al3+, the sum of Mulliken charge decreases on host layers where trivalent ions are Fe3+ or Cr3+, that results in the decreasing of inter-effect between metal cations and interlayer carbonate, water molecules and hydroxyls on layers.LDHs intercalated with Methyl Red (MR) has been synthesized by coprecipitation method, and the best synthesis condition in the mixed solution of water and glycol (ratio=1:1) with aging temperature at 70℃ and aging time for 24h. Based on characterizations, MR-LDHs containing nickel with supramolecular structures have been confirmed, and host-guest and guest-guest interactions exist in such systems. In MR-LDHs, interlayer guest adopt bi-layer arrangement and effect with host through electrostatic force and hydrogen bond.The characterization of photo and thermal stabilities show that MR-LDHs have more thermal stability than that of MR with decomposition temperature increasing from 207℃ to 250℃, and their photostability also improved. There results indicate that LDHs function as molecular container for MR and have restricted geometry effect on interlayer guests. In addition, photo stability of inorganic-organic hybrid materials (MR-LDHs and organic materials) have been improved, indicative of their specific application.