Fluorescence quantum yields and chromatic properties of poly(azomethine)s containing pyridine ring

Abstract

The poly(azomethine)s containing pyridine ring were synthesized in two stages and analyzed by electrochemical, optical and thermal analysis techniques. Pyridine with centric dialdehyde (DA-Py) and poly(azomethine-pyridine)s (PAZ-Py)s were synthesized by elimination and condensation reactions in organic solvent medium, respectively. The structures of the synthesized dialdehyde and poly(azomethine-pyridine)s were verified by nuclear magnetic resonance spectroscopy (NMR), Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet–visible spectroscopy (UV–Vis) analysis was performed and they were also characterized with cyclic voltammetry (CV), photoluminescence (PL) analysis, thermal analysis (TG-DTA) and Differential Scanning Calorimetric (DSC) analysis. According to thermal analysis, the initial degradation temperature (Ton) and glass transition temperature (Tg) values of PAZ-Py-1, PAZ-Py-2 and PAZ-Py-3 were found to be 126, 185, 139 °C and 102, 153 and 125 °C, respectively. According to fluorescence analysis, PAZ-Py-1 emitted four different colors of blue, green, orange and red emissions when excited at different wavelengths such as 340, 360, 380, 400, 420, 440 nm; 460, 480 nm; 500 nm; and 580 nm, respectively, in dimethylformamide (DMF) solutions. Also, two different colors were observed when excited at different wavelengths (blue emissions at 280, 300, 320, 340, 360, 380, 400, and 440 nm and orange emissions at 460, 480, 500, 520, 540, and 560 nm) in ethanol (EtOH) solutions. In addition, fluorescence quantum yields of PAZ-Py were found to be 9.0% and 11.0%; and 9.0% and 9.5% when excited at 440 and 460 nm in EtOH solution and when excited at 380 and 400 nm in DMF solutions, respectively.