Synthesis, characterization, thermal stability, conductivity and band gaps of monomer and oligo-4-[(thien-2-yl-methylene)amino] phenol


KAYA İ. , AYDIN A.

E-POLYMERS, 2008 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

In this study, the oxidative polycondensation reaction conditions of 4-[(thien-2-yl-methylene) amino] phenol (4-TMAP) by using oxidants such as air O-2, H2O2 and NaOCl were studied in an aqueous alkaline medium between 313 and 363 degrees K. The structures of the synthesized monomer and oligomer were confirmed by FT-IR, UV-vis, NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of oligo-4-[(thien-2-yl-methylene) amino] phenol (O-4-TMAP) was found to be 36% for air O-2 oxidant, 40% for H2O2 oxidant and 47% for NaOCl oxidant. According to TG analysis, the weight losses of 4-TMAP and O-4-TMAP were found to be 58.11% and 51.38% at 1273 degrees K, respectively. O-4-TMAP was shown higher stability against thermal decomposition. Also, electrical conductivity of the O-4-TMAP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical energy gaps (E-g') of 4-TMAP and O-4-TMAP were found to be -6.13, -6.02; -2.72, -2.69; 3.41 and 3.33 eV, respectively.