The Syntheses, Structures And Properties Of Functional Molecules-intercalated Layered Double Hydroxides

The aim of this thesis is the synthesis of a series of new bio-inorganic hybrid andorganic-inorganic hybrid materials on the basis of the Mg-Al-LDHs as the host and itsmemory effect and ion-exchange property, which are bridged through electrostatic interaction.The study on synthetic conditions and rules for these new materials and the exploration ofstructures, and the relationships between structures and properties for these new materials arealso carried out.1. Anti-tumor drugs, K₇[PTi₂W₁₀O₄₀]·6H₂O (PM-19) and 5-FU, are chosen as the guestspecies, two new bio-inorganic hybrid materials, Mg-Al-PTi₂W₁₀O₄₀ and Mg-Al-5-FU, havesuccessfully been constructed. The analyses indicate that two drugs is stabilized in the hostgallery, and that the orientation of 5-FU is different when changing the pattern of agingtreatment or the swelling agent. The release studies show that a rapid release of the drugduring the first 40 min is followed by a more sustained one, and that the total amount of drugreleased from hybrid material into the aqueous solution is completely different at pH 4 and 7,due to various release mechanism.2. A ubiquitous tripeptide biomolecule, Glutathione (GSH), has firstly been intercalatedinto layered double hydroxides with the reconstruction method. The analyses reveals that thecontrollably orientating GSH in three axis directions and second-staging structure in LDHsare successfully realized based on the starting GSH/LDHs mole ratios, the layer chargedensity (Mg/Al ratio) and the hydration degree, and that GSH molecules are stabilized in thehost interlayer by electrostatic interaction and intermolecular interaction. The results suggestthat the controllable orientation may be of substantial importance for the development ofnovel intercalation chemistry and tunable drug delivery systems with two ion-exchangedforms.3. Tetra-(8-hydroxy-quinolinato) boron complex (Bq) with tetrahedral-like geometry and3,3',4,4'-benzophenone tetracarboxylic anion (BPTC) with long-chain structure weresuccessfully intercalated into layered double hydroxides with ion-exchange method. Theanalyses indicated that the hydrothermal treatment could efficiently improve the reactionprocess, the purity and crystallinity of products, and that Bq and BPTC molecules steadilyarranged with C2 axis perpendicular to the layer plane and the J-type aggregate in the hostinterlayer, respectively. The fluorescence studies showed that compared with those observedin the dilute solutions of the guests, the spectra of Mg₃Al-Bq and Mg₃Al-BPTC evolved to thehigh-energy side and the low-energy side with increasing their loading, respectively, whichwere attributed to various arrangements of guests and the increased intermolecular interaction.Furthermore, their fluorescence intensity gradually decreased with increasing the intercalatedguest content due to the concentration quenching, and that Mg3Al-Bq exhibits enhancedsolid-state blue luminescence due to a more rigid and constrained environment of the host.