Side-Chain Liquid-Crystalline Polyoxetanes with a Spacer-Separated Azobenzene Moiety. III. Preparation and Characterization of Polyoxetanes Anchoring the Mesogen Cores of ap-Spacer-Substituted Phenyl 4-(4-Alkoxyphenylazo)benzoate in the Side Chain
Synthesis and Physico-Chemical Properties for 2-Oxochromen-6-yl 4-(4-Alkoxyphenylazo)benzoates
摘要:
This paper describes the preparation and thermal properties for homologous series of 2-oxochromen-6-yl 4-(4-alkoxyphenylazo)benzoates (compounds 1-n). Compounds 1-n show nematic phase exclusively, where the nematic-isotropic phase transition temperatures are between 293 degrees C for 1-4 and 256 degrees C for 1-8. Interestingly, compound 1-8 exhibits smectic A and re-entrant nematic phases in addition to the nematic one. The smectic A phase are characterized using a small angle X-ray diffraction study, indicating the smectic A phase has a partially bilayer molecular arrangement.
Thermal behavior of binary mixtures of isomers of different molecular structures and different lateral substituent positions
作者:H. A. Ahmed
DOI:10.1007/s10973-016-5471-1
日期:2016.8
benzoates (I n d) and their isomers 4-(3-fluorophenylazo)-phenyl-4′-alkoxybenzoates (II n). The latter two components differ from each other in the location inversion of the ester group, as well as in the exchange of the terminal substituents. For mixtures I n a/I n b, the CH3 group distributed SmA arrangement. In the mixtures of the two structurally different isomers, I n d/II n, the addition of one component
(4“ -烷氧基苯偶氮基)苯甲酸酯( -包括两个横向取代的偶氮/酯异构体,即2-(或3-)甲基- (或氟)取代的苯基4'二进位系统我 Ñ 一个-d ),进行热调查通过差示扫描量热法(DSC)进行鉴定,并通过偏光显微镜(PLM)鉴定相。所构建的相图由异构体组成,这些异构体在连接到单个组分上的侧向取代基的相对位置不同。另一个二元相图是从3-氟苯基-4'形成- (4“-alkoxyphenylazo)苯甲酸酯(我 Ñ d)和它们的异构体4-(3- fluorophenylazo) -苯基-4'- alkoxybenzoates(II Ñ)。后两个组分在酯基团的位置转化以及末端取代基的交换方面彼此不同。对于混合物I n a / I n b,CH 3基团为分布式SmA排列。在两种结构上不同的异构体I n d / II n的混合物中,一种组分与另一种组分的添加导致所有中间相的稳定性显着下降。
New wide-stability four-ring azo/ester/Schiff base liquid crystals: synthesis, mesomorphic, photophysical, and DFT approaches
作者:Nagwa H. S. Ahmed、Gamal R. Saad、Hoda. A. Ahmed、Mohamed Hagar
DOI:10.1039/c9ra10499b
日期:——
four-groups-based azo/ester/Schiff base liquid crystals, ((4-substitutedphenylimino)methyl)phenyl4-[2-(4-alkoxyhenyl)diazenyl]benzoate, Ina–d, were synthesized and analyzed for their mesomorphic stability and optical activity. In these compounds, a terminal alkoxy group of variable chainlengthfrom n = 6 to n = 16 carbons is attached to the end of a phenylazo benzoate moiety and the other end of the molecules
合成了新的基于四基团的偶氮/酯/席夫碱液晶,((4-取代苯基亚氨基)甲基)苯基4-[2-(4-烷氧基苯基)二氮烯基]苯甲酸酯,In a -d,并对其进行了分析。介晶稳定性和旋光性。在这些化合物中,链长从n = 6 到n = 16 个碳原子的末端烷氧基连接到苯偶氮苯甲酸苯酯部分的末端,分子的另一端连接到不同的极性紧凑取代基 X (CH 3 O、CH 3、H 和 Cl)。红外光谱, 1进行 H NMR、质谱和元素分析以确认所制备化合物的分子结构。使用差示扫描量热法 (DSC) 和偏光显微镜 (PLM) 的组合证实了介晶特性。光物理性质通过紫外-可见分光光度法进行研究。所有制备的同系物都表现出高热稳定性和宽温度介晶范围。通过密度泛函理论 (DFT) 估计所研究化合物的热和几何参数。结果表明,所有化合物都不是完全平面的,在 CH 处具有相对较高的扭曲部分N 部分及其扭曲角受所连接 X 基团的电子性质的影响。此外,由研究化合物的
Mesophase behavior of new linear supramolecular hydrogen-bonding complexes
作者:H. A. Ahmed、M. Hagar、A. Aljuhani
DOI:10.1039/c8ra07692h
日期:——
mesophase behavior of four new series of hydrogen-bonded supramolecularcomplexes (In/IIm) were investigated by differential scanning calorimetry and phases identified by polarized light microscopy. All hydrogen-bonded complexes formed from 4-alkoxyphenylazobenzoic acid (In) and 4-(4′-pyridylazophenyl)-4′′-alkoxybenzoates (IIm). The results revealed that the prepared complexes are dimorphic, possessing
通过差示扫描量热法研究了四个新系列的氢键超分子配合物(I n / II m )的热和中间相行为,并通过偏光显微镜鉴定了相。所有氢键配合物均由 4-烷氧基苯基偶氮苯甲酸 ( I n ) 和 4-(4'-吡啶基偶氮苯基)-4''-烷氧基苯甲酸酯 ( II m ) 形成。结果表明,所制备的配合物是二晶型的,具有近晶C相和向列相。本系列与之前研究的更简单的I n / III m和有角度的I n / IV m类似物之间的比较表明,增加介晶核心的长度和/或复合物的线性度会增加近晶结构的稳定性C相和向列相。
Multiple-responsive supramolecular vesicle based on azobenzene–cyclodextrin host–guest interaction
inclusion complexes (HPB@β-CD) could self-assemble into vesicles, which was driven by the hydrophobic interaction of the alkyl chain of HPB and the hydrogen bonds between neighboring β-CDs. The reversible assembly/disassembly of the vesicles could be simply regulated under UV or visible light irradiation. The reversible phase transformation between vesicles and microbelts could also be realized by adjusting
Switching Chirophilic Self‐assembly: From
<i>meso</i>
‐structures to Conglomerates in Liquid and Liquid Crystalline Network Phases of Achiral Polycatenar Compounds
The change of the interhelical self-assembly from enantiophilic to enantiophobic takes place by reduction of the alkyl chain length and leads to a phase transition from the achiral double gyroid via a tetragonal phase to a chiral triple networkphase, associated with a transition from an achiral to a mirror symmetry broken liquid.