Preparation and Characterization of poly(Azomethines) Containing Ether and Methylene Bridges: Photophysical,...

In this paper, a series of polyazomethines (PAZs) were prepared using dihydroxy substituted Schiff bases and 1,4-diiodobenzene. Also, different group effect such as methylene carbon and etheric oxygen bridges on photophysical, electrochemical, conductivity and thermal properties were clarified. The new polymeric materials structures were confirmed by means of ¹H-NMR, FT-IR and UV-vis measurements. The molecular weight distributions of polymers were determined with gel permeation chromatography (GPC) measurements. Photophysical behaviors of polymers were explored by UV-vis absorption and fluorescence measurements. TGA-DTA and DSC techniques have been used for the thermal characterization of the PAZs. Thermal data and fluorescence measurements showed that etheric oxygen bridge containing polymers have a bit higher char and emission intensity than the methylene carbon bridge carrying polymers. According to TG analysis, T_on values of P-2MPDP, P-2-OPDP, P-4-MPDP and P-4-OPDP were found as 210, 250, 249 and 233 °C, respectively. The HOMO-LUMO energy levels, electrochemical (E' _g ) and optical (E _g ) band gaps were calculated from cyclic voltammetry (CV) and UV-vis measurements, respectively. The electrochemical (E _g ') band gaps values of P-2MPDP, P-2-OPDP, P-4-MPDP and P-4-OPDP were calculated as 2.68, 2.32, 2.34 and 2.07, respectively. Additionally, four-point probe technique was used to measure solid state electrical conductivities of both doped and undoped states of the PAZs.