Materials 2009, 2(1), 38-61; doi:10.3390/ma2010038
Article

Mesomorphic Behavior of Symmetrical and Unsymmetrical Azomethines with Two Imine Groups

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Received: 26 November 2008; in revised form: 3 February 2009 / Accepted: 5 February 2009 / Published: 6 February 2009
(This article belongs to the Special Issue Liquid Crystals)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Seven symmetrical azomethines with two imine groups (HC=N) were synthesized by condensation of the benzene-1,4-dicarboxaldehydewith five amines (first group: A1-A5) and of the 2,5-thiophenedicarboxaldehyde with two amines (second group: AT1-AT2). Additionally, two unsymmetrical azomethines were obtained by a two step condensation of benzene-1,4-dicarboxaldehydewith pyren-1-amine(1st step) (abbreviated hereinafter as AP1) and then AP1 was reacted with4-dodecylaniline or 4-hexadecylaniline (2nd step) (third group: AP1A-AP1B). Liquid crystalline properties of the azomethines were studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and UV-vis spectroscopy in the function of temperature [UV-vis(T)]. The Wide-Angle X-ray Diffraction (WAXD) technique was used to probe the structural properties of the azomethines. Mesomorphic behavior was observed for symmetrical and unsymmetrical azomethines, obtained from the benzene-1,4-dicarboxaldehyde and symmetrical ones prepared from 2,5-thiophenedicarboxaldehyde and different amineshaving aliphatic chains. Based on the POM and DSC measurements the following mesophases were detected: nematic, smectic A, smectic C, smectic F (I), smectic G (J).
Keywords: Symmetrical and unsymmetrical azomethines; Schiff bases; liquid crystals; nematic and smectic phases; polymorphism
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MDPI and ACS Style

Iwan, A.; Janeczek, H.; Jarzabek, B.; Rannou, P. Mesomorphic Behavior of Symmetrical and Unsymmetrical Azomethines with Two Imine Groups. Materials 2009, 2, 38-61.

AMA Style

Iwan A, Janeczek H, Jarzabek B, Rannou P. Mesomorphic Behavior of Symmetrical and Unsymmetrical Azomethines with Two Imine Groups. Materials. 2009; 2(1):38-61.

Chicago/Turabian Style

Iwan, Agnieszka; Janeczek, Henryk; Jarzabek, Bozena; Rannou, Patrice. 2009. "Mesomorphic Behavior of Symmetrical and Unsymmetrical Azomethines with Two Imine Groups." Materials 2, no. 1: 38-61.

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