Rational design of dual-functional coordination polymers integrating fluorescent sensing of 8-nitroguanine

Coordination polymers with reliable fluorescent sensing performance are of considerable interest for the development of luminescent functional materials. In this work, two transition-metal coordination polymers, CP1 and CP2, were constructed using two different multicarboxylate organic ligands in combination with Ni(II) and Cu(II) ions, respectively. Single-crystal X-ray diffraction analyses reveal that both compounds adopt two-dimensional layered architectures but differ significantly in metal coordination environments and secondary building units, leading to distinct structure–property relationships. Benefiting from their good stability and strong blue luminescence in aqueous media, CP1 and CP2 were explored as fluorescent probes for the detection of 8-nitroguanine (8-NG), a biomarker associated with oxidative and nitrative stress. Both materials exhibit efficient fluorescence quenching responses toward 8-NG, with Stern–Volmer quenching constants of 8.84 × 10 4  M −1 for CP1 and 1.08 × 10 5  M −1 for CP2, along with good selectivity, rapid response, and excellent recyclability. These results demonstrate the potential of these coordination polymers for fluorescence sensing of 8-NG in aqueous systems and provide useful insights into the structure-directed design of coordination-polymer-based fluorescent sensors.