Non-symmetric liquid crystal trimers. The first example of a triply-intercalated alternating smectic C phaseElectronic supplementary information (ESI) available: characterization and thermal analysis of the trimers and their intermediates. See http://www.rsc.org/suppdata/jm/b4/b404319g/
摘要:
我们合成了含有三种不同中生单元和两种柔性间隔物的非对称液晶三聚体,并展示了一种新的共晶改性--三重交叠交替共晶 C 相。
Photoorientation of a Liquid-Crystalline Polyester with Azobenzene Side Groups: Effects of Irradiation with Linearly Polarized Red Light after Photochemical Pretreatment
作者:Ingo Zebger、Michael Rutloh、Uwe Hoffmann、Joachim Stumpe、Heinz W. Siesler、Søren Hvilsted
DOI:10.1021/ma034517h
日期:2003.12.1
transformation of the bulky Z-isomers to the rodlike E-isomeric formed by the red light. The aligned E-azobenzene side groups become strongly J-aggregated. Very high values of dichroism of about 0.8 and birefringence of about 0.3 were generated as a result of this combination of the photoinduced orientation process and the thermotropic self-organization, which take place simultaneously under the irradiation
与常规的蓝光光取向方法相反,当以线性方式照射液晶侧链聚合物的膜时,产生与入射光的电场矢量平行的4-氰基-4'-烷氧基偶氮苯侧基的取向。偏光红光。聚酯的特征是近晶相和向列相g24S X 26S A34N46i和形成J聚集体的强烈趋势。该方法需要通过用紫外线照射或暴露于高功率密度的可见光进行光化学预处理,以产生一定浓度的Z-异构体,该Z-异构体破坏任何初始的取向顺序和J-聚集体。取向过程是协同的,而光致变色部分的光诱导取向导致亚烷基间隔基甚至主链段向同一方向排序。此两步过程的最可能机理是将庞大的Z异构体进行角选择性转化为由红光形成的棒状E异构体。对齐的E-偶氮苯侧基强烈J聚集。二色性非常高的值约为0.8,双折射约为0。由于在照射条件下同时发生的光致取向过程和热致自组织的这种结合,产生了图3的产物。该过程导致膜的单轴扁长次序,而常规的光取向导致双轴扁长次序。这两个不同的三维阶次已通过FTIR偏振
Impact of terminal group on azobenzene liquid crystal dimers for photo-responsive optical storage devices
new series of photo responsive dimers bearing different terminal functional groups (-CN, -COOEt, -OMe) and variable aliphatic spacers have been synthesized and investigated in detail. The molecular structures of the new materials were proved using different spectroscopic techniques and their liquidcrystal self-assembly was characterized using differential scanning calorimetry (DSC), polarized light
已经合成并详细研究了三个新系列的具有不同末端官能团(-CN、-COOEt、-OMe)和可变脂肪族间隔物的光响应二聚体。使用不同的光谱技术证明了新材料的分子结构,并使用差示扫描量热法 (DSC)、偏光显微镜 (POM) 和 X 射线衍射 (XRD) 表征了它们的液晶自组装。此外,在溶液中详细研究了它们的光开关行为。结果表明,几乎所有的二聚体材料都是介晶的,要么表现出向列相,要么同时表现出近晶 A 相和向列相。在紫外线照射下,材料显示出有趣的光开关特性,在 40 秒内达到光静止状态,在溶液中达到约 35 小时的热背弛豫时间。最后,制造的设备验证了所报告的光存储设备材料的潜力。
(<i>E</i>)-(4-Hydroxyphenyl)(4-nitrophenyl)diazene, (<i>E</i>)-(4-methoxyphenyl)(4-nitrophenyl)diazene and (<i>E</i>)-[4-(6-bromohexyloxy)phenyl](4-cyanophenyl)diazene
作者:Xinjiang Huang、Genevieve H. Kuhn、Vladimir N. Nesterov、Boris B. Averkiev、Benjamin Penn、Mikhail Yu. Antipin、Tatiana V. Timofeeva
DOI:10.1107/s010827010201627x
日期:2002.10.15
Syntheses and X-ray structural investigations have been carried out for (E)-(4-hydroxyphenyl)(4-nitrophenyl)diazene, C12H9N3O3, (Ia), (E)-(4-methoxyphenyl)(4-nitrophenyl)diazene, C13H11N3O3, (IIIa), and (E)-[4-(6-bromohexyloxy)phenyl](4-cyanophenyl)diazene, C19H20BrN3O, (IIIc). In all of these compounds, the molecules are almost planar and the azobenzene core has a trans geometry. Compound (Ia) contains four and compound (IIIc) contains two independent molecules in the asymmetric unit, both in space group P (1) over bar (No. 2). In compound (Ia), the independent molecules are almost identical, whereas in crystal (IIIc), the two independent molecules differ significantly due to different conformations of the alkyl tails. In the crystals of (Ia) and (IIIa), the molecules are arranged in almost planar sheets. In the crystal of (IIIc), the molecules are packed with a marked separation of the azobenzene cores and alkyl tails, which is common for the solid crystalline precursors of mesogens.