Synthesis of π-conjugated network polymers based on triphenylamine (TPA) and tetraphenylethylene (TPE) as building blocks via direct Pd-catalyzed reactions and their application in CO2 capture and explosive detection

Abstract

In this study, we report the synthesis of π-conjugated network polymers via palladium-catalyzed direct arylation polycondensation of triphenylamine (TPA) and tetraphenylethylene (TPE) with different active substrates. Moreover, six conjugated porous polymers were obtained (named as TPA-TPA-MA, TPA-PB-MA, TPA-TFB-MA, TPA-TPE-MA, TPE-PB-MA, and TPE-TFB-MA). Then, the fluorescence properties in the solid and dispersed states, the corresponding microporous structures, and the Brunauer–Emmett–Teller (BET) surface areas of all polymers were well studied. Among the obtained materials, TPA-PB-MA possessed not only largest BET surface area (686 m² g⁻¹) and largest pore volume (0.716 cm³ g⁻¹), but also the smallest pore size of 0.823 nm. These properties are very beneficial for the application of TPA-PB-MA in CO₂ storage and PA sensing. At 1 bar, TPA-PB-MA demonstrated the significant CO₂ uptake of 2.70 and 1.35 mmol g⁻¹ at 273 and 298 K, respectively. Furthermore, TPA-PB-MA was most sensitive and selective towards PA recognition. The K_SV constant was measured as 4.0 × 10⁴ M⁻¹.