scholarly journals Liquid Crystalline Compounds in the Thiophene Series, Part 7+

1993 ◽  
Vol 48 (12) ◽  
pp. 1807-1820 ◽  
Author(s):  
Gerhard Koßmehl ◽  
Frank Dirk Hoppe
Keyword(s):  
Liquid Crystalline ◽  
Phosphonium Salts ◽  
Scanning Calorimetry ◽  
Azomethine Group ◽  
Temperature Range ◽  
H Nmr ◽  
Chemical Structures ◽  
Liquid Crystalline Phases ◽  
Elemental Analyses ◽  
New Compounds

Compounds with two mesogenic groups without terminal alkyl chains or other groups containing thiophene systems have been prepared from α.ω-bis(5-formyl-2-thienyl)alkanes (series 1) and various phosphonium salts by Wittig-reaction. The chemical structures of the new compounds have been characterized by their elemental analyses, IR and 1H NMR spectra and MS. The liquid crystalline properties of these compounds were characterized by differential scanning calorimetry (DSC) and polarizing microscopy. Mesogenic cores with one thiophene system and two benzene systems give rise to liquid crystalline phases. These compounds with one vinylene group in each core (series 2 and 3) are mostly monotropic, those with two or three vinylene groups are enantiotropic liquid crystalline. Exchanging one vinylene group by a azomethine group in each core reduces the temperature range of the mesophase or destroys the liquid crystallinity completely. In contrast to E,E-1-(5-butyl-2-thienylvinyl)-4-(styryl)benzene (9) with no mesophase the corresponding all-E-α.ω-bis{5-[4-(4-styryl)styryl]-2-thienyl}alkanes (series 5) show over a wide temperature range with increasing inner chain length more and more high ordered mesophases. all-E-α.ω-Bis{5-[4-(4-phenylbuta-1.3-dienyl)styryl]-2-thienyl}alkanes (series 7) decompose in their mesophases.

Liquid Crystalline Epoxy Resin Cured with Azomethine Hardening Compounds

2015 ◽  
Vol 749 ◽  
pp. 22-24
Author(s):  
Ho Kyoung Choi ◽  
Jae Hyun Choi ◽  
Hyeoung Seok Lee ◽  
Jae Sik Na
Keyword(s):  
Liquid Crystalline ◽  
Glycidyl Ether ◽  
Optical Microscope ◽  
Diglycidyl Ether ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Azomethine Group ◽  
H Nmr ◽  
Chemical Structures ◽  
Liquid Crystalline Epoxy

Bisphenol of 4,4’-dihydroxy-N-benzylidene-4-aminophenol containing azomethine group was synthesized via condensation of an aromatic amine namely 4-aminophenol with p-hydroxybenz aldehyde. It’s epoxy derivate and epicholorohydrin produced the new liquid crystalline diglycidyl ether of 4,4’-dihydroxy-N-benzylidene-4-aminophenol. A new type of liquid crystalline epoxy and azoemthine hardening agent are characterized at 300°C for 10 min, using c11z as a catalyst. The chemical structures were confirmed by FT-IR,1H-NMR. The curing reaction with 4,4’-dihydroxy-N-benzylidene-4-aminophenol were carried out in the ratio of glycidyl ether of 4,4’-dihydroxy-N-benzy lidene-4-aminophenol/azomethine hardening 1:0.8. The degree of crystallinity studied by X-ray diffractometer, differential scanning calorimetry (DSC) and polarized optical microscope (POM).

Synthesis and Mesomorphism of Novel Star-Shaped Liquid Crystals Containing Donor-Acceptor Groups

2013 ◽  
Vol 395-396 ◽  
pp. 72-75 ◽  
Author(s):  
Dan Shu Yao ◽  
Jun He ◽  
Guo Hua Li ◽  
Qian Xu ◽  
Ying Gang Jia ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Liquid Crystalline Phases ◽  
Temperature Ranges ◽  
Donor Acceptor

A new class of three-armed star-shaped liquid crystals 5a-5d were synthesized, they used 1,3,5-trihydroxybenzene as a core, ω-[4-(p-ethoxybenzoloxy) phenoxycarbonyalkyl acid (3a, 3b) and ω-[4-(p-nitrobenzoloxy) phenoxycarbonyalkyl acid (3c, 3d) as mesogenic arms. Their chemical structures were confirmed by FTIR and 1H NMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that the three-armed star-shaped liquid crystals exhibited a broad range of liquid crystalline phases at moderate temperature. The mesogenic arm structures obviously affected the phase behavior. As the intermedius alkyl chain of the star-shaped compounds lengthened (from n=4 to n=8), their melting points decreased but mesomorphic temperature ranges increased. The temperatures when 5% weight loss occurred (td) were higher than 300°C, which revealed that the synthesized three-armed liquid crystals had a high thermal stability. Threadlike, droplet and schlieren texture, typical of nematic phase can be observed in the liquid crystalline state during heating or cooling process.

Synthesis and characterization of N-glucosylated dithiadiazepine derivatives through carbon-sulfur bond formation

2015 ◽  
Vol 21 (5) ◽  
pp. 269-272 ◽  
Author(s):  
Snehal A. Chavan ◽  
Avinash G. Ulhe ◽  
Baliram N. Berad
Keyword(s):  
Bond Formation ◽  
Synthesis And Characterization ◽  
Mass Spectral ◽  
H Nmr ◽  
Chemical Structures ◽  
Elemental Analyses ◽  
New Compounds ◽  
Sulfur Bond ◽  
C Nmr

AbstractNew 4,7-bis(arylamino)-2-tetra-O-acetyl-β-d-glucopyranosylimino-1,3,5,6-dithiadiazepines were synthesized via reaction of N-tetra-O-acetyl-β-d-glucopyranosyl isocyanodichloride with 1,6-diaryl-2,5-dithio-bis-ureas without using any catalyst. Thus, the synthesis of 7-membered heterocycles containing two sulfur and two nitrogen atoms through carbon-sulfur bond formation was explored. The chemical structures of these new compounds were elucidated by IR, 1H NMR, 13C NMR, mass spectral, and elemental analyses.

Liquid Crystalline Compounds in the Thiophene Series, Part 11+ Liquid Crystalline Thiophene Carboxylic Esters

1995 ◽  
Vol 50 (8) ◽  
pp. 1265-1274 ◽  
Author(s):  
Gerhard Koßmehl ◽  
Barbara Hirsch
Keyword(s):  
Liquid Crystalline ◽  
Polarized Light ◽  
Scanning Calorimetry ◽  
Crystalline Phases ◽  
H Nmr ◽  
Smectic Phases ◽  
Liquid Crystalline Phases ◽  
Nematic Phases ◽  
Optical Textures ◽  
Carboxylic Esters

The new series of ten 4,4'-bis(5-alkyl-2-thienylcarbonyloxy)azobenzenes (2a -2j) and ten 2,5-bis(5-alkyl-2-thienylcarbonyloxy)toluenes (3a -3j) were prepared. These, as yet unknown esters were characterized in relation to their structures by elemental analyses, IR, UV, 1H NMR spectra and MS. The azobenzene-esters 2a -2j which form liquid crystalline phases were studied by microscopy under polarized light and DSC (differential scanning calorimetry). Through the observation of the optical textures nematic phases were monitored. Only 2j has an additional smectic phase; 2h and 2i form monotropic smectic phases during cooling. The toluene-esters 3a -3j do not form liquid crystalline phases.

Liquid crystalline alkylthia-substituted novel phthalocyanines: synthesis and characterization

2014 ◽  
Vol 18 (01n02) ◽  
pp. 139-148 ◽  
Author(s):  
Buket S. Erdoğan ◽  
Devrim Atilla ◽  
Ayşe G. Gürek ◽  
Vefa Ahsen
Keyword(s):  
Liquid Crystalline ◽  
Metal Salt ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Elemental Analyses ◽  
Diffraction Patterns ◽  
Columnar Mesophases ◽  
New Compounds ◽  
Hexagonal Columnar

Methylene-bridged tetra- and octa-alkylthia substituted metal free- and Ni ( II ) phthalocyanines were synthesized from the corresponding phthalonitrile derivatives in the presence of the anhydrous metal salt ( NiCl 2) or a strong organic base. The new compounds were fully characterized by elemental analyses, UV-vis, IR, NMR and mass spectra. The mesogenic properties of these materials were studied by differential scanning calorimetry, optical microscopy and X-ray diffraction investigations. X-ray diffraction patterns of the mesophase confirmed that the tetra- and the octa-substituted compounds formed hexagonal columnar mesophases (Colh). The mesogenic properties of these compounds were compared to that of their octa alkythia substituted phthalocyanine derivatives in the literature.

Synthesis and characterization of novel liquid and liquid crystalline phthalocyanines

2004 ◽  
Vol 08 (10) ◽  
pp. 1175-1186 ◽  
Author(s):  
Mahmut Durmuş ◽  
Colette Lebrun ◽  
Vefa Ahsen
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Metal Salt ◽  
Electronic Spectroscopy ◽  
Scanning Calorimetry ◽  
Elemental Analyses ◽  
Columnar Mesophases ◽  
New Compounds ◽  
Hexagonal Columnar

Peripheral and non-peripheral tetra(13,17-dioxanonacosane-15-hydroxy) substituted metal free-, Ni (II) and Zn (II) phthalocyanines have been synthesized from the corresponding phthalonitrile derivatives in the presence of the anhydrous metal salt ( NiCl 2 and Zn ( OOCCH 3)2) or a strong organic base. The new compounds have been characterised by elemental analyses, IR, NMR, mass spectra and electronic spectroscopy. The mesogenic properties of these new materials were studied by differential scanning calorimetry (DSC), optical polarised microscopy and X-ray investigations. The effects of peripheral or non-peripheral substitution of (13,17-dioxanonacosane-15-hydroxy) to the phthalocyanine ring are also investigated. It is found out that non-peripheral substituted phthalocyanine derivatives (4a-c) are liquid at room temperature whereas, peripheral substituted phthalocyanine derivatives (7a-c) exhibit ordered discotic hexagonal columnar mesophases ( Col h) at room temperature.

Synthesis and Characterization of Bowl-Shaped Liquid Crystals with a Core of Calix[6]arene

2011 ◽  
Vol 396-398 ◽  
pp. 2202-2205
Author(s):  
Dan Shu Yao ◽  
Feng Li ◽  
Hao Jie Wang ◽  
Xiao Yun Li ◽  
Mei Tian ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cholesteric Phase ◽  
Chemical Structures ◽  
Liquid Crystalline Phases ◽  
Clearing Temperature ◽  
Mesomorphic Properties

A new kind of bowl-shaped liquid crystals were designed and synthesized by esterification. They used a calix[6]arene as central unit and ω- cholesteric alkyl diacid monoester as mesogenic arms. Their chemical structures were confirmed by FTIR and 1HNMR spectra, their mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-Ray Diffraction (XRD) measurements. The results showed that the kind of calix[6]arene bowl-shaped liquid crystals N1-N3 exhibited broad range liquid crystalline phases at moderate temperature, and they displayed cholesteric phase focal-conic texture in liquid crystal states. With increasing the flexibility of monomers M1-M3, the melting point and the clearing temperature decreased in the macromolecules.

Electron microscopy and diffraction of crystalline dendrimers and macrocycles

1993 ◽  
Vol 51 ◽  
pp. 1218-1219
Author(s):  
C. J. Buchko ◽  
P. M. Wilson ◽  
Z. Xu ◽  
J. Zhang ◽  
S. Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Liquid Crystalline ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Scanning Calorimetry ◽  
Tertiary Butyl ◽  
Phenyl Acetylene ◽  
Selected Area Electron Diffraction ◽  
Liquid Crystalline Phases ◽  
Resolution Electron

The synthesis of well-defined organic molecules with unique geometries opens new opportunities for understanding and controlling the organization of condensed matter. Here, we study dendrimers and macrocycles which are synthesized from rigid phenyl-acetylene spacer units, Both units are solubilized by the presence of tertiary butyl groups located at the periphery of the molecule. These hydrocarbon materials form crystalline and liquid crystalline phases which have been studied by differential scanning calorimetry, hot stage optical microscopy, and wide-angle x-ray scattering (WAXS).The precisely defined architecture of these molecules makes it possible to investigate systematic variations in chemical architecture on the nature of microstructural organization. Here we report on the transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high resolution electron microscopy (HREM) studies of crystalline thin films formed by deposition of these materials onto carbon substrates from dilute solution. Electron microscopy is very attractive for gaining structural information on new molecules due to the scarcity of material to grow single crystals suitable for conventional crystallography.

Liquid crystalline polyureas with oligo(ethylene glycol) sequences

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Shahram Mehdipour-Ataei ◽  
Leila Akbarian-Feizi
Keyword(s):  
Liquid Crystalline ◽  
Spectroscopic Method ◽  
Polymerization Reaction ◽  
X Ray Diffraction ◽  
Subsequent Reaction ◽  
Scanning Calorimetry ◽  
Polar Solvents ◽  
X Ray ◽  
H Nmr ◽  
Ft Ir

AbstractA diamine monomer containing ester, amide and ether functional groups was prepared and its polymerization reaction with different diisocyanates to give main chain poly(ester amide ether urea)s was investigated. The monomer was synthesized via reaction of terephthaloyl chloride with 4-hydroxybenzoic acid and subsequent reaction of the resulted diacid with 1,8-diamino-3,6-dioxaoctane. The polymers were characterized by FT-IR and 1H-NMR spectroscopic method and elemental analysis. The resulting polymers exhibited excellent solubility in polar solvents. Crystallinity of the resulted polymers was evaluated by wide-angle X-ray diffraction (WXRD) method, and they exhibited semi-crystalline patterns. The glass transition temperatures (Tg) of the polymers determined by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) were in the range of 88-112 °C. The temperatures for 10% weight loss (T10) from their thermogravimetric analysis (TGA) curves were found to be in the range of 297-312 °C in air. Also the prepared polyureas showed liquid crystalline character.

scholarly journals Synthesis, Characterization, and Antimicrobial Activity of Methyl-2-aminopyridine-4-carboxylate Derivatives

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
S. Nagashree ◽  
P. Mallu ◽  
L. Mallesha ◽  
S. Bindya
Keyword(s):  
Antimicrobial Activity ◽  
Spectral Studies ◽  
H Nmr ◽  
Chemical Structures ◽  
Elemental Analyses ◽  
Ft Ir

A series of methyl-2-aminopyridine-4-carboxylate derivatives,3a–f,were synthesized in order to determine theirin vitroantimicrobial activity. The chemical structures of the synthesized compounds were confirmed by elemental analyses, FT-IR, and1H NMR spectral studies. Among the synthesized compounds,3cand3dshowed good antimicrobial activity compared to other compounds in the series.

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