Synthesis and Characterization of New Derivatives of Thiazole with Liquid Crystalline properties

A new two series of liquid crystalline Schiff bases containing thiazole moiety with different length of alkoxy spacer were synthesized, and the relation between the spacer length and the liquid crystalline behavior was investigated. The molecular structures of these compounds were performed by elemental analysis and FTIR, 1HNMR spectroscopy. The liquid crystalline properties were examined by hot stage optical polarizing microscopy (OPM) and differential scanning calorimetry (DSC). All compouns of the two series display liquid crystalline nematic mesophase. The liquid crystalline behaviour has been analyzed in terms of structural property relationship. Keywords: Thiazole, Liquid crystal, Heterocyclic, Schiff bas

Physical Properties of Pure and Nano Agdoped Liquid Crystalline Compounds Containing 1,3,4-Oxadizole Unit

Dielectric properties and other physical properties such as electrical conductivity (AC) and relaxation time or activation energy have been studied for two systems pure LC [V]6,6, [V]7,6, [V]8,6, [V]6,7, [V]7,7 and [V]8,7 and their doped with silver nanoparticles. The results show the increasing in real dielectric permittivity έ with increasing length terminal chain. So the real dielectric permittivity increasing with raising temperature. To compare between the values of at (400) Hz and (4000) Hz we observe these values at the low frequency are larger than that in high frequency. Generally, one can see that the doping of Ag nano particles effectively reduced the permittivity of the LC materials with its large electric dipole moment. The electrical conductivity value for pure LC samples in general increases  with increasing temperature. So we observed increasing of  electrical conductivity values at high frequency. The time scale is discussed in terms of the Arrhenius plot. Generally, with increasing the temperature the time period that spend by molecules at the transition state will increase. The activation energy Ea values show the increase in the activation energy to the doped systems.

Synthesis, characterization and comparative study the microbial activity of some heterocyclic compounds containing oxazole and benzothiazole moieties

New derivatives of five member heterocyclic compounds containing oxazole and benzothiazole rings are reported. These compounds have been characterized by elemental analysis, FT-IR and 1H NMR spectroscopy. This study was designed to show the microbial activity difference for two types of five member heterocyclic rings. The compounds were screened for antibacterial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aerugenosa in nutrient agar medium, and for antifungal activity against Aspergillus niger and Candida albicans in Sabouraud,s dextrose agar medium. The results show that the derivatives containing benzothiazole moiety are more active than the derivatives containing oxazole moiety

Synthesis and Characterization of Liquid Crystalline Behaviour of New Materials Incorporating Two Heterocyclic 1,3,4-Oxadiazole and 1,3,4- Thiadiazole Rings (NJC)

Abstract The synthesis and mesomorphic properties of 5-(4-methoxyphenyl)-2-[2-(4'-nalkoxy)-1,3,4-thiadiazole-5-methylenethio]-1,3,4-oxadiazole (series [VI] n ), were described for the number of the carbon atoms in alkoxy chains varying from 1-8

A study on removal characteristics of <i>o</i>-, <i>m</i>-, and <i>p</i>-nitrophenol from aqueous solutions by organically modified diatomaceous earth

<div><p></p><p>The natural diatomaceous earth (DAT) was modified with surfactant of hexadecyltrimethylammonium bromide (HDTMABr) to form organic-modified diatomaceous earth (DAT-HDTMABr). The DAT and DAT-HDTMABr were characterized by X-ray fluorescence, X-ray diffraction, FT-IR and DTA-TG. The surface area was determined using Brunauer, Emmett, and Teller adsorption method. Cation exchange capacity was estimated using an ethylenediamine complex of copper method, and the modifier loading was calculated from the total carbon analysis. The ability of raw and organomodified diatomaceous earth to remove <i>o</i>-nitrophenol (ONP), <i>m</i>-nitrophenol (MNP), and <i>p</i>-nitrophenol (PNP) from aqueous solutions has been carried out at predetermined equilibration time, adsorbent amount, pH, and temperatures using a batch technique. The removal of ONP, MNP, and PNP from aqueous solutions by modified clay seems to be more effective than unmodified sample. The experimental equilibrium adsorption data were analyzed by four widely used two parameters, Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) isotherm equations. Kinetic studies showed that pseudo-second-order described the adsorption experimental data better than the pseudo-first-order kinetic model. Based on the calculated thermodynamic parameters, such as enthalpy (Δ<i>H</i>), entropy (Δ<i>S</i>), and Gibb’s free energy changes (Δ<i>G</i>), it is noticeable that the adsorption of ONP, MNP, and PNP by DAT and DAT-HDTMABr adsorbents was carried out spontaneously, and the process was exothermic in nature.</p></div