Structural Design, Preparation And Characterization Of Novel Fluorescence And Photochromic Materials Based On Metal Organic Framework

Fluorescence materials have attracted more attentions for decades, especially the applications in people’s daily life and scientific research. What’s more, the development of functional fluorescence materials promote the diversification of application. The fluorescence modulation materials response to specialized stimulation which lead to specialized transformation of fluorescence through molecular modification, structure designing, intermolecular interaction and different stimulation. Fluorescence modulation materials attracted the attention of researchers for its potential application in molecular switch, sensor, display and optical storage devices. In this thesis, we design and prepare supramolecular and micromolecular based on macrocycle fluorescence ligands. These functional ligands with more coordination sites act as the antenna to absorb light and produce emission. MOF materials were synthesized via hydrothermal method and the properties were characterized through a series of characterization methods. The main achievement are listed as follows:1. In order to modify the coordination and fluorescence properties of the materials, three kinds of macrocycle fluorescence ligands were prepared through change the ligand group. PYTPY（4’-（4-pyridyl）-2,2’:6’,2’’-terpyridine） could acts as the electron acceptor due to its deficient electron structure. DMATPY（4′-（4-N,N′-dimethylaminophenyl）-2,2′:6′,2″-terpyridine） send strong light emission, which make it to be a perfect fluorescence sensor. CPTPY（4′-4-carboxyphenyl）- 2′:6′,2″-terpyridine) was prepared with a more carboxyl on end position of PYTPY, which make it possible to construct various structure.2. We construct a D-A coordination complex Cd（NO₃）（HCOO）（H₂O）（PYTPY）（1）, the PYTPY is designed as the electron acceptor, and the formic acid generated from the decomposition of DMF during the hydrothermal reaction acts as the electron donor. In this complex, the moleculars formed close packing structure due to the intermolecular hydrogen bond interaction, and the intermolecular distance fits to the distance range of forming excimer. So this complex can form excimer in solid state and modify the fluorescence and photochromic property under light irradiation.3. PYTPY is choosed to be the electron acceptor and the chloride acts as the electron donor to construct a D-A coordination complex CdCl₂（PYTPY）（2）. This compound is loose packing, and out of range of the excimer forming distance. In this case the compound（2） can’t form excimer in solid state, but it can form excimer in DMF solution, which can also modify the fluorescence and photochromic properties of the material through light irradiation. Constructing a supramolecular Cd₃Cl₆（PYTPY）₂（3）based on PYTPY to understand the fluorescence intensity change with the external force. This layered molecular is constructed with supramolecular Cd-Cl cluster.4. Design and construct micromolecular CdCl₂（DMATPY）（4）and Zn（CPTPY）₂（5）as the fluorescence sensor based on DMATPY and CPTPY. Due to their electron- rich ligand, the electron density would be rearranged accompany with the interaction between the complex and metal ion which caused the fluorescence change simultaneously.