Pyrazine-tetheredconjugated microporous polymers for silver nanoparticle dispersion toward enhanced catalytic reduction of p-nitrophenol and p-fluoronitrobenzene

Two pyrazine-based conjugated microporous polymers (CMPs), Py–PZ CMP and TPE–PZ CMP, were synthesized via Sonogashira–Hagihara coupling between 2-amino-3,5-dibromopyrazine (ADBPZ) and ethynyl-functionalized pyrene (PyT) or tetraphenylethylene (TPET) monomers. Both CMPs exhibit moderate porosity, high thermal stability, and distinct morphologies. Owing to the presence of amino-functionalized pyrazine nodes, the CMP frameworks enable the in situ reduction of Ag⁺ions, resulting in uniformly dispersed silver nanoparticles without the need for external reducing agents. The resulting Ag@PZ-CMP composites were comprehensively characterized, confirming homogeneous silver distribution and preservation of the polymer framework. These Ag-decorated CMPs demonstrate efficient heterogeneous catalytic activity toward the reduction of nitro compounds, including p-nitrophenol (p-NP), following pseudo-first-order kinetics. The catalytic performance is strongly influenced by the polymer backbone and silver loading. Moreover, the catalysts exhibit good recyclability with minimal loss of activity over repeated cycles. Overall, this work presents an environmentally benign strategy for the rational design of robust and reusable Ag-based CMP catalysts.