| Metal ions play an important role in the physiological activities of the human body. Too high or too low concentration of metal ions in the body will lead to physiological system disorder and causes various diseases. On the other hand, with the development of the industry, a large number of metal ions are discharged into the environment, causing serious environmental pollution and threaten the health of human body. So the high sensitivity and dissolution ion probes are urgent needed. Organic luminescent materials have been widely concerned for its great application value in recent years. In 2001, academician Tang Benzhong found the aggregation-induced emission materials, which is a great breakthrough of the design and synthesis of organic luminescent materials. After more than ten years of development, many of such materials have been synthesized and applied into practical application. Schiff base is a kind of very important ligands. People can prepare all kind of Schiff base compounds with different structure and properties by changing the type of reactant. Schiff base can recognize various metal ions through its coordination sites. The Schiff bases with large conjugate structure often show aggregation-induced emission (AIE) behavior and achieve ion recognition based on the mechanism of AIE. Based on the above research background, this paper mainly carried out the following experiment content:1. Two Schiff-base compounds (1-2) were prepared successfully through the reaction of diaminomalenitrile with triphenylamine or N-Phenylcarbazole, and their optical properties in pure solvents and aggregation state were investigated. The results show that subtle difference on the structure would influence their properties apparently. In acetonitrile, two compounds show great potential for the highly selective and sensitive detection of copper ions. The mixture of compound 2 with copper ions displays nice performance in cell bio-imaging. Two different types of single crystals of compound 1 were obtained with interesting polymorph-dependent fluorescence. Their crystal structures indicate that compact π…π stacking would induce fluorescence quenching and change of emission peak. The solid of compound 2 in amorphous state show obvious different fluorescence compared with that of crystal.2. A series of Schiff-base compounds based on N-Phenylcarbazole (1-8) were designed and prepared, all the compounds have been characterized by NMR, mass spectrometry and infrared spectroscopy. Because this series of compounds have similar molecular structure, the structure-activity relationship between the structure and optical properties of molecules can be explored through the differences of their optical properties. The obtained crystal structures of part compounds show similar stacking structure. Most of the eight compounds display AIE behavior, but the AIE behavior of the compounds containing hydroxyl or not is different. Compounds 1 and 7 can coordinate with metal ion, trivalent metal ions can induce obvious fluorescence emission of the acetonitrile solution of compound 1. The mixed solution of zinc ion and compound 7 has a strong fluorescence emission, and can be used in biological imaging. Based on the Complex of compounds 7 with copper ion, we predict the coordination model of the complex of compound 7 with zinc ion.3. Cis-trans isomer and polymorphism of 9-(4-(4-nitrostyryl)phenyl)-9H-carbzole (1) were obtained unexpectedly. Each isomer has two polymorphs, which was characterized by X-ray single crystal diffraction. The stacking structure of trans-isomers is more closely than that of cis-isomers. In the mixture of acetonitrile/water, trans and cis isomers display different AIE behavior. The experiment of SEM and DLS show that trans-isomer aggregate into different nanoparticles in the mixture at different water fractions, which originate from the difference in solubility and polarity of the mixtures. |
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