A Novel Benzoxazole-Functionalized Conjugated Mesoporous Polymer for Highly Sensitive and Selective Detection of Fe2+ and Fe3.

Conjugated micro/mesoporous polymers (CMPs) have emerged as versatile platforms for designing advanced functional materials. In this study, a novel benzoxazole-functionalized CMP, TFPA-DBD, was rationally synthesized, featuring a spherical morphology, well-defined mesoporous structure and robust thermal/chemical stability. When dispersed in DMF, TFPA-DBD exhibits a selective "turn-off" fluorescence response toward Fe²⁺ and Fe³⁺ ions, achieving low detection limits (LOD) of 0.56 µM and 0.72 µM, respectively. Importantly, TFPA-DBD demonstrates rapid response, high selectivity and strong anti-interference capability during sensing process. The fluorescence quenching mechanism originates from synergistic effects between Fe²⁺/Fe³⁺ ions and the nitrogen/oxygen sites within the benzoxazole units, and combines with absorption competition quenching (ACQ) sensing mechanism. Additionally, TFPA-DBD enables the straightforward visual identification of Fe²⁺ and Fe³⁺ ions using test paper mode, detectable by the naked eye. Practical applicability was validated through reliable recovery performance in real water samples, highlighting its potential for environmental monitoring applications. This work expands the library of functional CMPs and underscores their utility in developing high-performance sensing systems for transition metal ion detection.