Research Abstract |
We have prepared rigidly linear π-conjugated polymers by organometallic polycondensation using nickel and palladium complexes. These π-conjugated polymers were electrically conductive after doping, and showed electrochemically active and luminescent properties. The synthesized polymers contain poly(arylene)s and poly(aryleneethynylene)s composed of pyrimidopyridine, pyridopyradine, 3,4-ethylenedioxythiophene, and pyrimidine. We have revealed their photoluminescent, electrically conducting, and electrochemical responses, as well as their intermolecular interaction and packing structure in the solid originated from the rigidly linear structure. Spectroscopy and powder X-ray diffraction methods gave fundamental information about the polymers. The π-conjugated polymers are usually photoluminescent and sometimes show electroluminescence. The polymers give a high viscosity due to their rigidly linear structure and exhibit a strong dichroism in stretched films. In the course of the polymerization, formation of intermediate organo-nickel and-palladium complexes is strongly suggested. We prepared model compounds for the intermediates and analyzed their molecular structure. The obtained π-conjugated polymers take p2gg or face-to-face aggregated packing structure in the solid due to the intermolecular interaction, and the packing mode influenced efficiency of the luminescence. The ease of oxidation and reduction of the polymers reflect the basic electronic properties of the repeating units.
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