139056-52-3Relevant academic research and scientific papers
New wide-stability four-ring azo/ester/Schiff base liquid crystals: Synthesis, mesomorphic, photophysical, and DFT approaches
Ahmed, Hoda. A.,Ahmed, Nagwa H. S.,Hagar, Mohamed,Saad, Gamal R.
, p. 9643 - 9656 (2020/03/19)
New four-groups-based azo/ester/Schiff base liquid crystals, ((4-substitutedphenylimino)methyl)phenyl 4-[2-(4-alkoxyhenyl)diazenyl]benzoate, Ina-d, were synthesized and analyzed for their mesomorphic stability and optical activity. In these com
Design, synthesis and liquid crystalline behavior of ethyl 4-((4-alkoxyphenyl)diazenyl)benzoates
Mehmood, Hasnain,Ahmad, Zahoor,Akhtar, Tashfeen,Siddiqi, Humaira M.,Iqbal, Asma,Hameed, Shahid,Tahir, Muhammad N.
, p. 14 - 23 (2018/06/27)
A series of ethyl 4-((4-alkoxyphenyl)diazenyl)benzoate is synthesized and the liquid crystalline behavior studied. Synthesized compounds are characterized by FTIR, 1H-NMR, Mass and single crystal XRD. Differential scanning calorimetry was carri
Mesophase behavior of new linear supramolecular hydrogen-bonding complexes
Ahmed,Hagar,Aljuhani
, p. 34937 - 34946 (2018/10/24)
Thermal and mesophase behavior of four new series of hydrogen-bonded supramolecular complexes (In/IIm) were investigated by differential scanning calorimetry and phases identified by polarized light microscopy. All hydrogen-bonded complexes formed from 4-
Monotropic or enantiotropic mesophases? Liquid-crystalline and solid state polymorphism 4-Chloro-1,3-phenylene bis-[4-(4-alkyloxyphenylazo)benzoates
Niezgoda, Izabela,Pociecha, Damian,Galewski, Zbigniew
, p. 59 - 66 (2014/06/09)
This article presents a homologous series of bent-core molecules consisting of a 4-chlororesorcinol as a central unit and 4-[(4-alkyloxyphenyl)diazenyl] benzoic acids as wings. With the use of polarizing optical microscopy (POM), thermal analysis (TOA) and differential scanning calorimetry (DSC) the mesogenic properties were detected. Furthermore, the X-ray diffraction (XRD) measurements were also performed for selected samples. Compounds of the above mentioned series form nematic, B6, and smectic C mesophases. An interesting phenomenon in the solid phase polymorphism was observed in some cases. In our experiment one crystalline form (CrI) melts to nematic phase while the second form (CrII) melts at higher temperature directly to isotropic phase. The solid state modification determines whether a monotropic and an enantiotropic mesophase is observed.
4-cyanoresorcinol-based bent-core mesogens with azobenzene wings: Emergence of sterically stabilized polar order in liquid crystalline phases
Alaasar, Mohammed,Prehm, Marko,May, Kathrin,Eremin, Alexey,Tschierske, Carsten
, p. 1703 - 1717 (2014/04/03)
A new series of azobenzene containing bent-core molecules incorporating 4-cyanoresorcinol as the central core unit exhibiting cybotactic nematic, rectangular, columnar, and different types of tilted smectic (SmC) phases are synthesized. The mesophase behavior and phase structures are characterized in bulk and freely suspended films using a variety of experimental techniques. Depending on the chain length and temperature a series of different mesophases is observed in these compounds, ranging from cybotactic nematic via paraelectric SmC phases, polarization randomized SmCsPR phases to ferroelectric and antiferroelectric SmC phases, associated with increasing size and correlation length of the polar domains. Spontaneous formation of chiral domains is observed in the paraelectric SmC and the SmCsPR phases and discussed in relation with superstructural chirality, bend elastic constants, and surface effects. Development of polar order in tilted smectic liquid crystalline phases (SmC) of bent-core mesogens is found to take place with increasing polar domain size in a series of distinct phases via a paraelectric and a new randomized polar SmC phase (SmCsPR) to a ferroelectric phase, which then becomes modulated and finally changes to an antiferroelectric phase.
Side-Chain Liquid-Crystalline Polyoxetanes with a Spacer-Separated Azobenzene Moiety. III. Preparation and Characterization of Polyoxetanes Anchoring the Mesogen Cores of a p-Spacer-Substituted Phenyl 4-(4-Alkoxyphenylazo)benzoate in the Side Chain
Ogawa, Hiroshi,Kanoh, Shigeyoshi,Motoi, Masatoshi
, p. 1649 - 1657 (2007/10/03)
Polyoxetanes anchoring the mesogen cores of p-spacer-substituted phenyl 4-(4-alkoxyphenylazo)benzoates through a pendant spacer, -CH2O(CH2)4O-, were prepared by a BF3-initiated cationic ring-opening polymerization of the corresponding oxetanes, followed by a fractional reprecipitation of the raw polymer products containing oligomer fractions. The polyoxetanes separated from the oligomers had their peak tops at molecular weights of around 10000-23000 in nearly mono- or dimodal molecular-weight dispersity curves determined by gel permeation chromatography, and indicated fan-shaped textures due to a smectic mesophase over a wide temperature range from about 250 °C to room temperature on heating and cooling processes by polarized optical microscopy. The formation of highly ordered assemblies of the pendant mesogens is ascribable to a cohesion of the 4-(4-alkoxyphenylazo)benzoate moiety in the mesogen core, which can form a larger dipole, due to forming a longer conjugated system from the ester carbonyl to the alkoxy tail, than that of the simple 4-alkoxybenzoate moiety of the mesogen core previously reported by us.
