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Mesomorphic Behavior of Symmetrical and Unsymmetrical Azomethines with Two Imine Groups
Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Street, 41-819 Zabrze, Poland
Laboratoire d’Electronique Moléculaire, Organique et Hybride, UMR5819-SPrAM (CEA-CNRS-Univ. J. FOURIER-Grenoble I), INAC Institut Nanosciences & Cryogénie, CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble Cedex 9, France
* Author to whom correspondence should be addressed.
Received: 26 November 2008; in revised form: 3 February 2009 / Accepted: 5 February 2009 / Published: 6 February 2009
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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Iwan, A.; Janeczek, H.; Jarzabek, B.; Rannou, P. Mesomorphic Behavior of Symmetrical and Unsymmetrical Azomethines with Two Imine Groups. Materials 2009, 2, 38-61.
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.
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.