Synthesis and Mesomorphic Properties of Azo Compounds Derived from Phenyl-and Thienyl-1,3,4-Thiadiazole

The synthesis and mesomorphic behaviour of new series of liquid crystals containing 1,3,4- thiadiazole and thiophene rings with azo central bond are reported (series 5a and 5b). All compounds of series 5a exhibit enantiotropic nematic mesophase and the higher homologues (n = 9 - 10) also show a monotropic smectic C phase. Series 5b show dimorphism SC - N (for n = 5 - 7 the SC is monotropic). These series are compared with the Schiff’s bases analogues, the imine bond gives rise to similar liquid crystals phase but larger mesomorphic range.

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Comparison of the Mesomorphic Properties Between Substituted Schiff's Bases Incorporating a Linear Hydrocarbon or Fluorinated Tail

Molecular Crystals and Liquid Crystals Science and Technology Section A Molecular Crystals and Liquid Crystals ◽

10.1080/10587259708045096 ◽

1997 ◽

Vol 308 (1) ◽

pp. 83-92 ◽

Cited By ~ 17

Author(s):

F. Guittard ◽

P. Sixou ◽

A. Cambon

Keyword(s):

Schiff’S Bases ◽

Schiff's Bases ◽

Mesomorphic Properties

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Synthesis and mesomorphic properties of esters derived from Schiff's bases containing 1,3,4-thiadiazole

Liquid Crystals ◽

10.1080/02678290412331304104 ◽

2004 ◽

Vol 31 (11) ◽

pp. 1531-1537 ◽

Cited By ~ 27

Author(s):

M. Parra ◽

J. Vergara ◽

J. Alderete ◽

C. Zúñiga

Keyword(s):

Schiff’S Bases ◽

Schiff's Bases ◽

Mesomorphic Properties

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Liquid Crystals VIII. The Mesomorphic Behavior of Some Optically Active Aromatic Schiff's Bases

Molecular Crystals and Liquid Crystals ◽

10.1080/15421407408083145 ◽

1974 ◽

Vol 27 (3-4) ◽

pp. 417-429 ◽

Cited By ~ 18

Author(s):

Joseph A. Castellano ◽

Chan S. Oh ◽

Michael T McCaffrey

Keyword(s):

Liquid Crystals ◽

Optically Active ◽

Schiff’S Bases ◽

Schiff's Bases

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Synthesis of New Heterocyclic Derivatives from 4-(3, 5-Dimethyl-1-phenyl-1H-pyrazol-4-ylazo)- benzoic acid

Baghdad Science Journal ◽

10.21123/bsj.7.1.727-736 ◽

2010 ◽

Vol 7 (1) ◽

pp. 727-736 ◽

Cited By ~ 1

Author(s):

Baghdad Science Journal

Keyword(s):

Hydrazine Hydrate ◽

Acid Hydrazide ◽

Azo Compounds ◽

Basic Medium ◽

Chloride Salt ◽

Aminobenzoic Acid ◽

Schiff’S Bases ◽

Schiff's Bases ◽

Thiosemicarbazide Derivative ◽

Hydrazide Derivative

In this work pyrazolin derivatives were prepared from the diazonium chloride salt of 4-aminobenzoic acid. Azo compounds were prepared from the reaction of an ethanolic solution of sodium acetate and calculated amount of active methylene compound namely, acetyl acetone to obtain the corresponding hydrazono derivative (1). Cyclocondensation reaction of compounds (1) with hydrazine hydrate and phenyl hydrazine in boiling ethanol affording the corresponding pyrazoline-5-one derivatives of 4-aminobenzoic acid (2,3). Then compound (3) was reacted with thionyl chloride to give the corresponding acid chloride derivative(4), followed by conversion into the corresponding acid hydrazide derivative (5) carboxylic acid thiosemicarbazide (11), esters (14,15), thioesters (16,17) and amides (18,19), when treated hydrazine hydrate, thiosemicarbazide, alcohols, alkylthiol and secondary amines in dry refluxing benzene; respectively. Schiff's bases (6-8) were prepared by refluxing of compound (5) with different aldehydes and ketons, then two compounds from the Schiff's bases were cyclized with ?-mercapto acetic acid to give (9 and 10). Furthermore, 1,2,4-triazole derivative (12) have been also prepared by refluxing thiosemicarbazide derivative with sodium hydroxide solution (4%) followed acidification of the result using (10%)hydrolic acid. Moreover, a thiadiazole derivative (13) has been prepared by treatment of thiosemicarbazide derivative with concentrated sulfuric acid as cyclyzing agent. Finally, oxadiazole derivative (20) has prepared by condensation of its acid hydrazide derivative with carbon disulfide in basic medium.

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Novel chiral liquid crystals based on amides and azo compounds derived from 2‐amino‐1,3,4‐thiadiazoles: synthesis and mesomorphic properties

Liquid Crystals ◽

10.1080/02678290701751434 ◽

2008 ◽

Vol 35 (1) ◽

pp. 55-64 ◽

Cited By ~ 28

Author(s):

M. L. Parra ◽

C. G. Saavedra ◽

P. I. Hidalgo ◽

E. Y. Elgueta

Keyword(s):

Liquid Crystals ◽

Azo Compounds ◽

Chiral Liquid Crystals ◽

Mesomorphic Properties

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EXHIBITION OF NEMATIC MESOPHASE IN BINARY MIXTURES OF SCHIFF'S BASES

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1975164 ◽

1975 ◽

Vol 36 (C1) ◽

pp. C1-393-C1-398

Author(s):

J. M. LOHAR

Keyword(s):

Binary Mixtures ◽

Schiff’S Bases ◽

Schiff's Bases ◽

Nematic Mesophase

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Synthesis and Mesomorphism of 1,1’-Disubstitued Ferrocene Liquid Crystals with a Schiff’s Base Bridge

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.428-429.162 ◽

2010 ◽

Vol 428-429 ◽

pp. 162-166

Author(s):

Qing Yan ◽

Ping Hu ◽

Wen Hao Yu ◽

Bi Qin Wang ◽

Ke Qing Zhao

Keyword(s):

Differential Scanning Calorimetry ◽

Liquid Crystals ◽

Alkyl Chain ◽

Melting Points ◽

Ferrocene Derivatives ◽

Scanning Calorimetry ◽

Schiff’S Base ◽

Polarized Optical Microscopy ◽

Nematic Mesophase ◽

Mesomorphic Properties

To investigate the influence of alkyl chain on thermotropic and mesomorphic properties of 1,1’-disubstitued ferrocene derivatives, two series of ferrocene derivatives containing Schiff's base, 1,1’-C8H17FcC6H4COOC6H4CH=NC6H4OOCC6H4R1 (R1 = H, OCnH2n+1, n = 2, 4, 6, 8 ) and 1,1’-C8H17FcC6H4COOC6H4CH=NC6H4N=NC6H4R2 (R2 = Br, Cl, CH3 ) have been synthesized and characterized by IR and 1H NMR. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) results showed that all compounds exhibit nematic mesophase. The results show that the flexible alkyl chain connecting with ferrocene moiety could lower the melting points and clearing points, favor the formation of nematic mesophase.

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