Studies on the Substituent Effects of Side Ring and Side Chain of Banana-Shaped Molecules

• Main Authors: Jin-Yi Liau, 廖晉逸
• Other Authors: Kwang-Ting Liu
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/57230360937127317042

碩士 === 國立臺灣大學 === 化學研究所 === 93 === A series of banana-shaped organic molecules which have a central aromatic ring (C ring) modified by different substituents and four side aromatic rings linked by ester bonds were synthesized and characterized in our earlier work. In this research, we aim toward the modification of terminal side chains on the molecules. Results show that the modification of chain length will alter the mesophases due to different molecule geometry. In addition, we modified the molecules with several different linkages but maintain the same carbon chain length. Results show that molecules with ester linkages prefer a larger mesophase temperature range and higher transition temperature between liquid crystal mesophase and isotropic phase comparing to ether linkages. Molecules with pure alkyl side chains are unfavorable to form liquid crystal mesophases. On the other hand, the addition of substitents on side ring B will diminish the appearance of liquid crystal mesophases except fluorine. Also, the replacement of central benzene ring (C ring) with a pyridine ring results in the disappearance of liquid crystal mesophases as well.