Synthesis and applications of fused heterocyclic polymers containing naphthoquinone structures†

In the field of modern polymer chemistry, developing synthetic strategies to construct fused heterocyclic polymers with novel and unique structures holds significant research value. In this study, we designed and developed a simple and efficient multicomponent polymerization method for constructing fused heterocyclic polymers containing naphthoquinone structures in their main chains. Two synthesized key monomers, 1,4,5,8-anthracenetetrone and 1,1′-dimethyl-5,5′-biindole, were polymerized with aniline in a model polymerization reaction, during which the reaction conditions, such as catalyst, temperature, reaction time, monomer ratio and so on, were systematically screened and optimized. A series of fused heterocyclic polymers containing naphthoquinone structures with high molecular weights (M_n ∼ 5000) and relatively high yields (around 70%) were successfully synthesized. The synthesized polymers, attributed to the quinone groups and fused heterocyclic structures presented in the polymer main chain, exhibited excellent thermal stability, narrow electrochemical bandgaps, and desirable fluorescence properties. Leveraging these properties, polymers P2, P5, P13, and P14 were successfully applied in the development of selective fluorescent chemosensors for Fe³⁺ detection. Additionally, a possible polymerization mechanism was proposed in this study, and the binding mechanism between the polymers and metal ions was elucidated. This provides reference and theoretical support for future research in this domain.