Synthesis and spectroscopic characterization of polymer and oligomers of ortho-phenylenediamine |
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Authors: | Ricardo H. Sestrem Richard Landers Marcia L.A. Temperini |
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Affiliation: | a Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26.077, CEP 05513-970, São Paulo, SP, Brazil b Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, CP 6165, CEP 13083-970, Campinas, SP, Brazil c Laboratório Nacional de Luz Síncrotron, CP 6192, CEP 13084-971, Campinas, SP, Brazil |
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Abstract: | Poly(ortho-phenylenediamine) and oligomers of ortho-phenylenediamine were chemically synthesized and characterized by UV-vis, 1H and 13C NMR, FTIR and resonance Raman spectroscopies. Polymerization of ortho-phenylenediamine in HCl medium with ammonium persulfate only leads the trimer compound, in disagreement with some previous reports. Nevertheless, in acetic acid medium it was possible to prepare a polymer constituted by ladder phenazinic segments with different protonation levels and quinonediimine rings (polyaniline-like). X-ray absorption at N K-edge (N K XANES), X-ray photoelectron (XPS) and Electron paramagnetic resonance (EPR) spectroscopies were used to determine the different kinds of nitrogen presents in this class of polymer. N K XANES spectrum of poly(ortho-phenylenediamine) shows the band of N nitrogen of non-protonated phenazinic rings at 398.2 eV. In addition, XPS and N K XANES data confirm the presence of different types of protonated nitrogens in the polymeric poly(ortho-phenylenediamine) chain and the EPR spectrum shows that the polymer has a very weak polaronic signal. |
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Keywords: | Raman spectroscopy Conducting polymers Polyaniline XANES |
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