Synthesis and property of 1,1,3,3-tetramethylisoindolin-2-yloxyl-containing polythiophene

Recently radical polymer has increasedly been investigated as an electroactive material in organic rechargeable batteries, electrochemical supercapacitors and photovoltaic cells. The novel isoindoline nitroxide-containing polythiophene derivatives, such as poly(3-(1’,1’,3’,3’tetramethylisoindolin-2’-yloxyl-vinylene)-thiophene) (PTTMIO) and poly(3,4-di(1’,1’,3’,3’-tetramethyl-isoindolin-2’-yloxyl-amino)-thiophene-co-thiophene) (PT2TMIO), were synthesized by the incorporation of 1,1,3,3-tetramethylisoindolin-2-yloxyl (TMIO) to polythiophene, respectively. These polymers were further characterized and their properties, such as fluorescence, electron paramagnetic resonance (EPR) and electrochemical performance, were also evaluated. It is found that PTTMIO and PT2TMIO displayed the similar fluorescence and characteristic EPR spectra of isoindoline nitroxides, with typical hyperfine splitting, nitroxide g-values and nitrogen isotropic hyperfine coupling constants. Moreover, PTTMIO and PT2TMIO possessed higher capacities, higher electrochemical redox activity and lower impedance than that of polythiophene (PTh). Furthermore, PT2TMIO show good capacitance maintenance (contained 87.2% capacity after 1000 cycles) due to a rapid charging-discharging process. Therefore, isoindoline nitroxide-containing polythiophene derivatives can be considered as the potential candidates for novel good electrode materials.