Chemical synthesis and characterization of a new soluble conducting polymer

A new conjugated aromatic poly [(pyrrole-2, 5-diyl)-co-(4-nitrobenzylidene)] (PPNB) have been prepared by polycondensation of 4-nitrobenzaldehyde and pyrrole catalyzed by Maghnite-H+ was reported. Maghnite-H+ is a montmorillonite sheet silicate clay, which was exchanged with protons. The results reveal that the yield of PTTM increases with time and Mag-H amount. The conjugated polymer was characterized by means of FT-IR spectroscopy, UV-vis spectroscopy, matrix-assisted laser desorption/ionization time of-flight (MALDI-TOF) mass spectrometry, thermogravimetric analysis (TGA) and X-ray diffraction. The X-ray data showed the presence of a backbone form of the PPNB formed. The new polymer is a useful precursors to small-bandgap polymers based on poly (heteroary1ene methines) and is also a useful model system for the investigation of the effects of IT-conjugation length on the electronic and optical properties of the conjugated polymers. The electrical conductivity of the synthesized polymer was sigma =0.02251 Omega cm(-1). The results obtained by means of the optical measurements and analyzed by different models, show clearly that our material (PPNB) is a good semi-conductor, where the optical gap separating the extrema of the valence and the conduction band is estimated at 3.7 +/- 0.2 eV. This result is in good agreement with those prepared with tetrahedral amorphous carbon. (c) 2012 Elsevier B.V. All rights reserved.