A Convenient Synthesis of Novel Mercapto-Ended Azobenzene Derivatives
摘要:
Treatment of the product from the Diazo-Coupling reaction of p-alkylaniline with 1,3-dibromopropane in THF affords intermediate compounds n-C(n)H(2n+1)AzoO(CH2)(m)Br. Subsequent treatment of these intermediate with thiourea in ethanol at reflux temperature leads to the desired azobenzene derivatives, n-C(n)H(2n+1)AzoO(CH2)(m)SH (n=4,6,8,10,12; m=3,5), in good yield. The structure data of these new compounds was presented in detail.
Liquid-Crystalline Polymorphism of Symmetrical Azobananas: bis(4-(4-alkylphenyl)azophenyl) 2-nitroisophtalates
摘要:
In this paper we present a series of novel compounds, bis(4-(4-alkylphenyl)azophenyl) 2-nitroisophtalates, which exhibit nematic and banana-type liquid-crystalline phases. The alkyl chain length varies from 1 to 18 carbons. The first ten members of this series exhibit nematic phase. The last eleven compounds exhibit banana-type liquid crystalline phases. The propyl and pentyl derivatives have extra second type of banana mesophase.
Mechanically induced disorder–order transitions have been studied in fluid surfactant solutions or polymer thermotropic liquidcrystals. However, isothermally induced ordered phases do not persist after cessation of shear, which limits their technological applicability. Moreover, no such stimuli‐responsive materials involving biomacromolecules have been reported although biopolymer liquids are gaining
Lactic acid derivative, liquid crystal composition containing same and
申请人:Canon Kabushiki Kaisha
公开号:US05167857A1
公开(公告)日:1992-12-01
An optically active lactic acid derivative represented by the following formula (I): ##STR1## wherein R is a saturated or unsaturated hydrocarbon group of a linear, branched or cyclic structure having 4 to 20 carbon atoms; Ra is --CO--Rb or --CH.sub.2 --Rc wherein Rb is a releasable chemically active group, and Rc is a releasable chemically active group; and C with * represents an asymmetric carbon atom.
Ferroelectric liquid crystal device containing optically active azo or
申请人:Canon Kabushiki Kaisha
公开号:US04979805A1
公开(公告)日:1990-12-25
A ferroelectric liquid crystal composition containing an optically active mesomorphic compound represented by the following formula (I) or (II): ##STR1## wherein R.sub.1 and R.sub.2 are respectively an alkyl, and C with * represents an asymmetric carbon atom. The mesomorphic compound provides the ferroelectric liquid crystal composition with an extended operational life in a liquid crystal device.
Azopolyesters with Intrinsic Crystallinity and Photoswitchable Reversible Solid‐to‐Liquid Transitions
作者:Jie Li、Qiu‐Yu Zhang、Xiao‐Bing Lu
DOI:10.1002/anie.202311158
日期:2023.11.13
Azobenzene-based polyesters (azopolyesters) from copolymerization of azobenzene-based epoxides with cyclic anhydrides possess remarkable intrinsic crystallinity and novel photoinduced reversible solid-to-liquid transition abilities, owing to photoinduced trans-cis isomerizations of azobenzenes being inlaid with soft alkyl side-chain. This represents a new design strategy for the synthesis of reversible
An amphiphilic anionic azobenzene derivative, soluble in water, formed a monolayer on an aqueous subphase containing a water-soluble polycation. The monolayers were transferred onto solid substrate by the Langmuir-Blodgett (LB) technique. XPS measurements showed that ion exchange reaction proceeded almost completely at the air-water interface and that the ratio of the monomer unit of the polycation to the azobenzene was almost unity. UV/vis absorption and IR measurements indicated that the azobenzene photoisomerized reversibly in the LB films on alternate illumination with UV and vis light. Furthermore, a reversible morphological change induced by light was observed in the LB films with AFM. Before illumination, the surface of the single-layer LB film was very smooth with a surface undulation of less than 1 nm. On illumination with UV light, however, a number of hills, with the height of ca. 5 nm and the diameter of the base of ca. 100 nm, appeared on the film surface. These structures almost disappeared on illumination with vis light. This indicates that the widely accepted assumption that photoisomerization should not change the two-dimensional structures significantly does not hold in the present case.