| Layered inorganic materials have been extensively studied due to growing interest in their catalytic activity, ion-exchange capacity and physical-chemical stability. The important feature of these materials is their ability to incorporate guest molecules which form highly ordered arrays between adjacent layers. On the basis of this feature, many novel assembly structures can be tailored at the molecular level through the design of the host and the guest species. These assembly structures have been utilized widely in the preparation of functional materials such as catalysts, conducting polymers, energy storage devices and receptors. In this thesis, hydrotalcite, α-zirconium phosphate and MoO3 were investigated as host compounds. Inorganic layers of hydrotalcite are positively-charged while inorganic layers of α-zirconium phosphate and MoO3 are negatively-charged. Drug molecules, DNA molecules, Eu complex and polyaniline were selected as guest compounds, respectively for developing new drug deliver system, DNA functional materials, new catalyst for copolymerization of propylene oxide (PO) and CO2, and conductive shell materials. 1. Phenoxymethylpenicillin-Intercalated Hydrotalcite as a Bacteria Inhibitor. Phenoxymethylpenicillin (PMP) has been reversibly intercalated into a layered double hydroxide, and the resulting composite exhibits effective antibacterial activity. Powder X-ray diffraction indicates that the PMP molecules are interdigitated in between the inorganic layers, and under mild acidic media, the molecules are released gradually. Therefore a sustained-release antibacterial medication is envisioned on the basis of this inorganic-drug composite. To assess the antibacterial activity and sustained-release action of the HTP composite, antibacterial experiments have been conducted. Compared with those reported in previous references, our results answer the question whether drug released from HTP still be efficient or not, because phenoxymethylpenicillin is easily checked through antibacterial experiment while other drugs, such as vitamin A (C, E) and cardiovascular, having been reported to be intercalated between layers of HT compound in previous references are difficult to be checked. 2. Intercalation of DNA-Ethidium Complex into Layered Hydrotalcite. A new composite compound HT-DNA-ET has been prepared through intercalation of ethidium and DNA molecule into the layers of hydrotalcite (HT). The HT-DNA-ET compound has been investigated by various analytical methods such as X-ray diffraction, infrared, UV-vis and circular dichroism spectroscopy, element and thermogravimetric analyses. The interlayer distance of the HT-DNA-ET compound is 4.6 nm, larger than that of the pristine HT. Taking into account the structure of the DNA molecule and the ET molecule, it is proposed that there are two layers of DNA-ET composite between two adjacent HT sheets. The DNA molecules in the HT-DNA-ET compound retain their chemical and biological integrity. The HT-DNA-ET compound gave rise to photoluminescence of λem, max=610 nm under the excitation of a laser light of λex=488 nm. 3. Eu3+ and Lysine Co-intercalated α-Zirconium Phosphate and Its Catalytic Activity for Copolymerization of Propylene Oxide and CO2. A novel composite material, α-Zr(HPO4)2·1.5 Lysine·0.06 Eu3+ (designated ZLE), has been prepared through intercalation of L-lysine (Lys) molecules and Eu3+ ions into between the layers of α-Zr(HPO4)2 (α-ZrP). The preparation involves two steps. First, α-Zr(HPO4)2·1.85Lys (ZL) is obtained through the Lys molecules intercalated between the layers of the α-ZrP by ion exchange reaction, and second, the Eu complex is incorporated into the Lys-intercalated α-ZrP by solid grinding of EuCl3·6H2O and ZL. It is speculated that there are two layers of Eu complex lying between the two layers of Lys molecules located on the inner surface of α-ZrP, and the carboxyl groups of Lys coordinate with the Eu3+ ions. The photoluminescent spectrum of the composite ZLE shows that each unit of Eu3+ i... |
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