AIE-Active CO₂-Based Polycarbonate: A Fluorescent Probe for Sensitive Detection of Mn(VII), Cr(VI)

Excessive Mn(VII) and Cr(VI) ions threaten environmental safety and public health. As a result, effective environmental water quality monitoring is required, and the development of materials for rapid and precise detection of hazardous ions in aqueous solutions is imperative. In this study, carbon dioxide-based polycarbonates containing tetraphenylethylene skeletons-based groups (herein referred to as PPCTs) were synthesized in an unprecedented one-pot method using 4-(1,2,2-triphenylethenyl) phenol (T) as the monomer with carbon dioxide and propylene oxide. Fluorescence characterization indicated that modified PPCT retained the aggregation-induced luminescence properties of T. A significant overlap was observed between the ultraviolet absorption bands of the polymer and the MnO₄ ²⁻, and Cr₂O₇ ²⁻ ions, inducing an internal filter effect that resulted in fluorescence quenching of the PPCT solution. The probe demonstrated specific selectivity against interference, as well as high sensitivity toward these anions, with limits of detection as low as 47.8 nM, 0.438 μM, and 1.12 μM, respectively. Furthermore, the modified PPCT demonstrated enhanced thermal properties compared with those of conventional PPC materials, which are crucial for its application in harsh environments. This innovative material synthesized using CO₂ offers a new approach to ion detection in real samples and broadens the scope of poly(propylene carbonate) in fluorescence sensing applications.