scholarly journals Origin of green photoluminescence in four-ring bent-core molecules with ESIPT, selective sensing of zinc ions by turn-on emission and their liquid crystal properties

2018 ◽  
Vol 17 (10) ◽  
pp. 1386-1395 ◽  
Author(s):  
Venkatesh Gude ◽  
Duttanjali Rout ◽  
Mruganka Kumar Panigrahi ◽  
Kumar Biradha
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Photophysical Properties ◽  
Zinc Ions ◽  
Alkyl Chains ◽  
Turn On ◽  
Crystal Properties ◽  
Green Photoluminescence

Fluorescent four-ring symmetrical/unsymmetrical molecules containing alkyl chains of a varied number of –CH2– groups with a bent-core have been synthesized to explore their liquid crystalline (LC) and photophysical properties.

Inosose-Flüssigkristalle / Inosose Liquid Crystals

1990 ◽  
Vol 45 (7) ◽  
pp. 1084-1090 ◽  
Author(s):  
Klaus Praefcke ◽  
Bernd Kohne ◽  
Andreas Eckert ◽  
Joachim Hempel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
High Temperature ◽  
Liquid Crystalline ◽  
Structural Features ◽  
Lyotropic Liquid Crystal ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alkyl Chains

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.

scholarly journals The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

2020 ◽  
Vol 16 ◽  
pp. 175-184 ◽  
Author(s):  
Itamar L Gonçalves ◽  
Rafaela R da Rosa ◽  
Vera L Eifler-Lima ◽  
Aloir A Merlo
Keyword(s):  
Liquid Crystal ◽  
Relative Position ◽  
Liquid Crystalline ◽  
Condensation Reaction ◽  
Ammonium Thiocyanate ◽  
The Other ◽  
Amide Derivatives ◽  
Crystal Properties ◽  
Benzoyl Chlorides ◽  
Membered Heterocycle

A series of novel thiourea and amide liquid crystals containing 5-membered isoxazoline and isoxazole rings were synthetized and the liquid crystal properties studied. Thioureas were obtained using a condensation reaction of benzoyl chlorides, arylamines and ammonium thiocyanate. The amides, on the other hand, were the byproduct of a quantitative reaction which used potassium cyanate as the starting material. Thiourea and amide derivatives were predominantly SmA mesophase inductors. A nematic mesophase was observed only for thioureas and amides containing an isoxazole ring. Additionaly, the liquid crystal behavior was also dependent on the relative position of nitrogen and oxygen atoms on the 5-membered heterocycle.

scholarly journals Photophysical and Photochemical Properties of Green Fluorescent Liquid Crystalline Systems

2003 ◽  
Vol 58 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Ivo Grabchev ◽  
Jean-Marc Chovelon
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Photophysical Properties ◽  
Orientational Order ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed ◽  
Photochemical Properties ◽  
Green Fluorescent ◽  
Naphthalimide Dye

The photophysical properties of polymer-dispersed liquid crystal systems, containing naphthalimide dye as fluorescent units are reported. Investigations have been carried out on some 1,8- naphtalimide derivatives both in isotropic and anisotropic media, and their photophysal properties have been described. The orientational order parameters of the dyes in nematic liquid crystal ZLI 1840 have been determined. The photostability of the dye/liquid crystal systems has been investigated and the effect that the substituents in the naphthalimide structure have upon the orientation of the dye was discussed.

Chiroptical switching caused by crystalline/liquid crystalline phase transition of a chiral bowl-shaped molecule

2016 ◽  
Vol 52 (24) ◽  
pp. 4585-4588 ◽  
Author(s):  
Masaki Yamamura ◽  
Kimiya Sukegawa ◽  
Daichi Okada ◽  
Yohei Yamamoto ◽  
Tatsuya Nabeshima
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Crystalline Phase ◽  
Phosphorus Atom ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Alkyl Chains ◽  
Crystalline Phase Transition

The liquid crystal of a chiral bowl-shaped molecule having a central-phosphorus atom and long alkyl chains was developed.

scholarly journals An unsymmetrical porphyrin and its metal complexes: Synthesis, spectroscopy, thermal analysis and liquid crystal properties

2009 ◽  
Vol 74 (10) ◽  
pp. 1097-1104 ◽  
Author(s):  
Changfu Zhuang ◽  
Xuexin Tang ◽  
Dong Wang ◽  
Aiqing Xia ◽  
Wenhui Lian ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Liquid Crystalline ◽  
Thermal Studies ◽  
Luminescent Properties ◽  
Quantum Yields ◽  
Scanning Calorimetry ◽  
Crystal Properties

The synthesis and characterization of a new unsymmetrical porphyrin liquid crystal, 5-(4-stearoyloxyphenyl)phenyl-10,15,20-triphenylporphyrin (SPTPPH2) and its transition metal complexes (SPTPPM, M(II) = Zn, Fe, Co, Ni, Cu or Mn) are reported. Their structure and properties were studied by elemental analysis, and UV-Vis, IR, mass and 1H-HMR spectroscopy. Their luminescent properties were studied by excitation and emission spectroscopy. The quantum yields of the S1 ? S0 fluorescence were measured at room temperature. According to thermal studies, the complexes have a higher thermal stability (no decomposition until 200?C). Differential scanning calorimetry (DSC) data and an optical textural photograph, obtained using a polarizing microscope (POM), indicate that the porphyrin ligand had liquid crystalline character and that it exhibited more than one mesophase and a low-lying phase transition temperature, with transition temperatures of 19.3 and 79.4?C; the temperature range of the liquid crystal (LC) phase of the ligand was 70.1?C.

scholarly journals Preparation and Aggregation-Induced Emission of New 1,3,5-Triazine-2,4,6-tricarboxamide with Liquid Crystal Properties

2018 ◽  
Vol 34 (4) ◽  
pp. 1741-1748 ◽  
Author(s):  
ABDULHAMID UMAR ◽  
MUSTAFFA SHAMSUDDIN
Keyword(s):  
Liquid Crystal ◽  
Solid State ◽  
Liquid Crystalline ◽  
Crystalline Material ◽  
Aggregation Induced Emission ◽  
Liquid Crystal Material ◽  
Crystal Properties ◽  
Thermal Data ◽  
Active Liquid ◽  
Liquid Crystalline Material

The combination of aggregation-induced emission (AIE) and liquid crystal properties generates solid-state efficient luminescent liquid crystal materials. Here in, we reported the synthesis of 1,3,5-triazine-2,4,6-tricarboxamide and utilized it as a supramolecular organic motif for the AIE-active liquid crystal material. The compound exhibits high-intensity emission maxima at 417 and 468 nm in the solid state with excitation at 254 nm, whereas it shows weak emission in the solution phase. Also, this compound behaves as liquid crystalline material and shows columnar hexagonal mesophase with endothermic peaks at 73.4oC, 185.6oC, and exothermic peaks were observed at 181.9oC and 66.1oC with focal conic fan shape texture. The thermal data showed that the compound is stable up to 200oC.

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