Triphenylamine–Anthracene-Based Conjugated Microporous Polymers for the Detection and Photocatalytic Degradation of Organic Micropollutants

Triphenylamine (TPA)–anthracene (AN)-based conjugated microporous polymers (CMPs), namely PTPA-AN-9,10 and PTPA-AN-2,6, were synthesized by the Suzuki–Miyaura cross-coupling reaction of tris(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-amine with 9,10-dibromoanthracene and 2,6-dibromoanthracene, respectively. The as-synthesized polymers exhibited cauliflower-like nanoscale morphology , high Brunauer–Emmett–Teller surface area of 362 m2/g, and thermal stability up to 458 °C in the case of PTPA-AN-2,6. Interestingly, PTPA-AN-9,10 showed bright cyan fluorescence in tetrahydrofuran dispersion and exhibited fluorescence-based sensing of various nitroaromatics, where 2,4,6-trinitrophenol exhibited the lowest limit of detection of 34 μM and the highest Stern–Volmer constant (KSV) of 5.8 × 103 L mol–1. On the other hand, PTPA-AN-2,6 showed efficient photocatalytic reduction of various nitroaromatic micropollutants such as p-nitrophenol (p-NP) (k = 0.164 min–1 and turnover frequency (TOF) = 0.769 h–1) and degradation of Congo red from water with ultrafast kinetics (k = 0.047 min–1 and TOF = 0.024 h–1) which are much better than most of the previously reported CMPs. These polymers were recovered using simple filtration and were recycled four to five times without losing their catalytic efficiency significantly for p-NP reduction as well as dye degradation. In general, TPA-based CMPs have been used as efficient multitasking materials for the sensing of nitroaromatic micropollutants and photocatalytic degradation of Congo red dye as well as p-NP to its value-added product p-aminophenol.