Synthesis and characterization of novel polyphenol species derived from bis(4-aminophenyl) ether: Substituent effects on thermal behavior, electrical conductivity, solubility, and optical band gap

In this study, four different Schiff bases namely, 4,4'-oxybis[N-(2-hydroxybenzilidene)aniline] (2-HBA), 4,4'-oxybis[N-(4-hydroxybenzilidene)aniline)] (4-HBA), 4,4'-oxybis[N-(3,4-dihydroxybenzilidene)aniline] (3,4-HBA), 4,4'-oxybis[N-(4-hydroxy-3-methoxybenzilidene)aniline (HMBA) were synthesized. These Schiff bases were converted to their polymers that have generate names of poly-4,4'-oxybis[N-(2-hydroxybenzilidene)aniline] (P-2 HBA), poly-4-4'-oxybis[N-(4-hydroxybenzilidene)aniline] (P-4-HBA), poly-4,4'-oxybis[N-(3,4-dihydroxybenzilidene)aniline] (P-3,4-HBA), and poly-4,4'-oxybis[N-(4-hydroxy-3-methoxybenzilidene)aniline] (PHMBA) via oxidative poly-condensation reaction bv Using NaOCl as the oxidant. Four different metal complexes were also synthesized from 2-HBA and P-2-HBA. The structures of the compounds were confirmed by FTIR, UV-vis, (1)H and (13)C NMR analyses. According to (1)H NMR spectra, the polymerization of the 2-HBA and 4-HBA largely maintained With C-O-C Coupling, whereas the polymerization of the 3,4-HBA and HMBA largely maintained with C-C coupling. The characterization was made by TG-DTA, size exclusion chromatography and Solubility tests. Also, electrical conductivity of the polymers and the metal complex compounds were measured, showing that the synthesized polymers are semiconductors and their conducivities call be increased highly via doping with iodine ions (except PHMBA). According to UV-vis measurements, the optical band gaps (E,) were found to be 3.15, 2.06, 3.23, 3.02, 2.61, 2.47, 2.64, 2.42, 2.83, 2.77, 2.78, and 2.78 for 2-HBA, P-2-HBA, 4-HBA, P-4-HBA, 3,4-HBA, P-3,4-HBA, HMBA, PHMBA, 2-HBA-Cu, 2-HBA-Co, P-2-HBA-Cu, and P-2HBA-Co, respectively. (c) 2008 Wiley Periodicals, Inc.