New azo ligands containing azomethine groups in the pyridazine-based chain: Synthesis and characterization

Five, novel pyridazine-based azo chromophores were synthesized by the condensation reaction of 3, 6-bis((aminoethyl)thio)pyridazine with 5-(4-X-phenyl)-azo-salicylaldehyde (X = NO(2), Cl and Et), 5-(2,4-di-Cl-phenyl)-azo-salicylaldehyde and 5-(3,4-di-Cl-phenyl)-azo-salicylaldehyde. The dyes were characterized by elemental analysis, thermal analyses, IR, UV-vis, NMR and mass spectroscopy. Spectral characteristics of the dyes were investigated in four organic solvents of differing polarity; thermal studies indicate that the framework of dyes is stable Lip to 220 degrees C. Complexation of the azo dyes with Cu(II) gave subtle changes in their absorption spectra. (C) 2008 Elsevier Ltd. All rights reserved.