Synthesis and characterization of a three-ring bent-core compound  

作　　者：TANG Yanhong MEI Chongyu LI Shaojun WANG Yan WANG Xingdong WANG Lixiang YAN Donghang YE Cheng 

机构地区：[1]State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry. Chinese Academy of Sciences, Changchun 130022, China [2]Center for Molecular Science, Laboratory of Organic Solid, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China

出　　处：《Chinese Science Bulletin》2005年第17期1849-1853,共5页

基　　金：This work was supported by the Special Funds for Major State Basic Research Projects(Grant No.2002CB6 13400);the National Natural Science Foundation of China(Grant Nos.90301008and 20025413).

摘　　要：To investigate the vacuum-deposited films of the banana-shaped mesogens, we prepared a three-ring bent-core (that is, banana-shaped) compound m-bis(4-p- octoxysryrenyl)benzene (m-OSB) and used it as a prototype for studying the related film physics. Herein the synthesis and the structural characterization of m-OSB are reported. 13C and 1H NMR spectra and IR spectrum confirm that m-OSB has a symmetric and all-trans conformation. The results of differential scanning calorimetry, polarizing optical microscopy and X-ray diffractometry indicate that no liquid crystalline phase but two crystalline phases are present in this material: phase I (T<66℃) and phase II (66℃<T<157℃); an isotropic state is observed at above 157℃. Combining the X-ray diffraction and the electronic diffraction, we assign the room-temperature crystalline phase I to orthorhombic sys-tem and P212121 space group with cell parameters of a = 7.43 ?, b = 6.34 ?, c = 72.07 ?, and α = β = γ = 90°. Molecular modeling reveals that the molecules in the unit cell adopt a layered structure with an antiferro-electric alignment. The structure of phase II is very similar to that of phase I. Nonlinear optical measurement shows that m-OSB is active for the second harmonic generation (SHG). Such characteri-zation of the bulk material is necessary for the understand-ing of the growth and microstructures in the films.To investigate the vacuum-deposited films of the banana-shaped mesogens, we prepared a three-ring bent-core （that is, banana-shaped） compound m-bis（4-p-octoxysryrenyl）benzene （m-OSB） and used it as a prototype for studying the related film physics. Herein the synthesis and the structural characterization of m-OSB are reported.^13C and ^1H NMR spectra and ^1R spectrum confirm that m-OSB has a symmetric and all-trans conformation. The results of differential scanning calorimetry, polarizing optical microscopy and X-ray diffractometry indicate that no liquid crystalline phase but two crystalline phases are present in this material： phase Ⅰ （T〈66℃） and phase Ⅱ （66~C〈T〈157℃）; an isotropic state is observed at above 157℃. Combining the X-ray diffraction and the electronic diffraction, we assign the room-temperature crystalline phase I to orthorhombie system and P212121 space group with cell parameters of a = 7.43A°. b=6.34A°, c=72.07A°, and α=β=γ=90°. Molecular modeling reveals that the molecules in the unit cell adopt a layered structure with an antiferro-eleetrie alignment. The structure of phase Ⅱ is very similar to that of phase Ⅰ. Nonlinear optical measurement shows that m-OSB is active for the second harmonic generation （SHG）. Such characterization of the bulk material is necessary for the understanding of the growth and microstructures in the films.

关 键 词：真空沉积薄膜 香蕉型介质 核心分子 分子结构 光谱 

分 类 号：O62[理学—有机化学]