Jordan Journal of Chemistry Vol. 2 No.2, 2007, pp. 133-144 JJC Characterization and Thermal Decomposition of Indolylidene Aniline Azo-Dyes Derivatives Salem A. Hameed* King Abdulaziz University, Faculty of Science, Chemistry Department P.O.Box 80203, Jeddah 21589, Saudi Arabia Received on May 31, 2007 Accepted on Sep. 30, 2007 Abstract New heterocyclic azo-dyes derived from aniline derivatives using indolyl aldehyde as a coupler have been prepared and investigated by elemental analysis, IR, 1 H-NMR and Uv- vis spectra furthermore, the spectral properties of the dyes, solvent effect and buffer solution pH effect have been studied for determination of pK a values (9.62-12.25) for all compounds. Kinetics of differential scanning calorimetry (DSC) of these compounds were measured. The activation energy and also critical temperature (T c ), glassy transition temperature (T g ) and melting point (T m ) temperatures were calculated. Keywords: Azo-dyes; Spectroscopy; pK a -Value; Differential Scanning Calorimetry (DSC). Introduction Azo-dyes are one of the most important and versatile classes of synthetic organic compounds,with an enormous variety of applications. [1,2] Technological applications of these dyes result from the combination of the properties of the azo-group and several types of aromatic-substituted ligands that confer to them intense color over the whole visible range, thermal and photochemical stability, non-complex synthetic methodologies and low costs of production. More recently, some of these dyes have been studied as materials for non-linear optical applications when they contain substituents on the aromatic rings with push-pull electron ability. [3,4] Azo-dyes as guests or attached to the polymer chains can undergo photo and thermal isomerization reactions from the most stable anti-form to the syn. In general, these reactions produce remarkable changes of the dipole moments of these molecules leading to photo induced optical birefringency. [5-7] The sequential reversible isomerization anti-syn-anti leads to the possibility of optical storage, photo induced switching, [8] formation of surface gratings. [9-11] In the present investigation concerned with preparation of new dyes, determined ionization constant, solvent effect and kinetic thermal analysis. * Corresponding author. E-mail : [email protected].
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Jordan Journal of Chemistry Vol. 2 No.2, 2007, pp. 133-144
JJC
Characterization and Thermal Decomposition of Indolylidene Aniline Azo-Dyes Derivatives
Salem A. Hameed*
King Abdulaziz University, Faculty of Science, Chemistry Department
P.O.Box 80203, Jeddah 21589, Saudi Arabia Received on May 31, 2007 Accepted on Sep. 30, 2007
Abstract New heterocyclic azo-dyes derived from aniline derivatives using indolyl aldehyde as a
coupler have been prepared and investigated by elemental analysis, IR,1H-NMR and Uv- vis
spectra furthermore, the spectral properties of the dyes, solvent effect and buffer solution pH
effect have been studied for determination of pKa values (9.62-12.25) for all compounds.
Kinetics of differential scanning calorimetry (DSC) of these compounds were measured. The
activation energy and also critical temperature (Tc), glassy transition temperature (Tg) and