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 π-conjugation length on the electronic and optical properties of the conjugated polymers. The electrical conductivity of the synthesized polymer was σ = 0.02251 Ω 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.

► Maghnite-H as catalyst.
► Poly [(pyrrole-2, 5-diyl)-co-(4-nitrobenzylidene)] was synthesized.
► The obtained polymer was shown good solubility in common organic solvents.
► Conduction band is estimated to 3.7 ± 0.2 eV.
► The electrical conductivity of the synthesized polymer was σ = 0.02251 Ω cm−1.