Synthesis And Self-assembly Behavior Of Polycatenar Compounds Based On Benzothiadiazole And Triazole Units

Liquid crystals (LCs) as supramolecular system which combine ordering with fluidity, have self-healing, adaptive and stimuli-responsive, therefore liquid crystals(LCs) become well self-assembly molecular materials.2,1,3-benzothiadiazole compounds and its application is one of the most active research in the optoelectronic materials’ filed due to their outstanding optical and electronic properties. 2,1,3-benzothiadiazole based LCs can improve the optical properties of such compounds. Triazole unit, results from Click reaction, has received much attention in organic and polymeric materials due to its advantage in designing soft materials. Recently the researchs in 2,1,3-benzothiadiazole liquid crystal and its optoelectronic properties has become a hotspot.In chapter 1, the latest research of liquid crystal formed by benzothiadiazole compounds is summarized. The brief introduction of organgels and chemosensors based on triazole core have summarized, a brief introduction of polycatenar liquid crystal has also been summarized.In chapter 2, a series of one-generation polycatenar compounds based on 2,1,3-benzothiadiazole and triazole units have been synthesized and characterized. By Suzuki reaction and Click reaction as the key procedure, a series of polycatenar compounds containing a 4,7-diphenyl-2,1,3-benzothiadiazole core and three alkoxy chains at each end was synthesized. Self-assembly structures in its pure state were investigated by POM, DSC, and XRD. The results show that these compounds can self-assembly into columnar liquid crystalline phase in its pure state. With the chain length increased, the clearing point has little change, but melting point has been increased. These compounds can self-assembly into organgel in different solvents and its fibrous aggregates were investigated by SEM. The spectrum data has demonstrated that there is large stokes shift in these compounds and highly fluorescent emission. Also experiments on cation recognition have been done, the results showed that these compounds have binding selectivity to Li+among a series of cation in in DMSO:DCM(v/v)(2/1). can be applied as chemosensors.In chapter 3, a second generation dendron based on 2,1,3-benzothiadiazole and triazole units has been synthesized and characterized. By Suzuki reaction and twice Click reaction as the key procedure, a dendron with twelve dedocyloxy chains was synthesized. Its self-assembly structure was investigated by POM, DSC, and XRD. The result showed that this compound could self-assembly into complicated cubic phase with the space group of Pm3n. It can also form organgel in different solvents. It also shows large Stokes shift in solution.In chapter 4, the detail synthesis procedure of these compounds and its corresponding experimental data for each compound are provided.