The studys of the discotic liquid crystal

• Main Authors: Chang-Rong Wen, 溫長榮
• Other Authors: C.K. Lai
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/86811999238763243488

碩士 === 國立中央大學 === 化學研究所 === 90 === Abstract A series of metal complexes：bis[2,5-bis(3,4,5-trialkoxyphenyl)- 1,3,4-oxadiazole]palladium (II), was prepared and characterized. Liquid crystalline properties of these palladium (II) complexes were studied and investigated by differential scanning calorimeter (DSC) and polarized optical microscopy (POM). The structures of the mesophases for palladium (II) complexes were also characterized and confirmed as rectangular columnar phase (Colr) or hexagonal columnar phase (Colh) depending on the carbon chain length by powder X-ray diffraction (XRD). The formation of mesophases was found to be sensitive to the numbers of the alkoxy side chains and the carbon length of the side chains. The results indicated that palladium (II) complexes with twelve alkoxy side chains exhibited columnar mesophases, however, all complexes with four or eight side chains showed only crystalline phase. The complexes with carbon length of 10, 12 and 14 displayed rectangular columnar phases (Colr) and the complex with carbon length of 16 displayed a hexagonal columnar phase (Colh). In fact, the complexes with carbon length of 10, 12 were room temperature liquid crystals. The crystal and molecular structures of the complex(comp. 3a, n =1) were determined by means of x-ray analysis. The complex was crystallizes in the monoclinic space group p21/c, with a = 8.7736(3) Å, b = 19.1568(6) Å, c = 15.7834(5) Å, β = 100.106(1)o, and Z=2.