Metallopolymers based on a polyazomethine ligand containing rigid oxadiazole and flexible tetramethyldisiloxane units

摘要

Soluble, easily processable polymer-metal complexes with improved optical and dielectric properties for optoelectronic functional materials were obtained. For this, a new polyazomethine (PAZ2) was prepared by the reaction of a siloxane dialdehyde and bis(formyl-p-phenoxymethyl) tetramethyldisiloxane with 2,5-bis(p-aminophenyl)-1,3,4-oxadiazole, and it was used as a ligand for Cu(II), Co(II), and Zn(II) ions on the basis of the presence of the electron-donor nitrogen atoms from the azomethine group and oxadiazole ring. The structure of the PAZ2 was determined by spectral [Fourier transform infrared (FTIR) and H-1-NMR spectroscopy] techniques. The metal complexation was proven by FTIR spectroscopy, and the silicon-to-metal ratios in the complexes were established by energy-dispersive X-ray fluorescence. The new materials were characterized by gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. The optical properties of PAZ2 and the derived metal complexes were studied by ultraviolet-visible and fluorescence spectroscopies. PAZ2 shows fluorescence emission, and it was significantly enhanced by metal complexation. The emission was enhanced by protonation; this behavior is useful, especially for sensors. The electrical properties were investigated by dielectric spectroscopy at various frequencies and temperatures, and this emphasized the existence of dipolar relaxations. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41631.