Ag@FONPs nanohybrids derived from a sulfur-functionalized dicarbene ligand: efficient catalysts and selective azide-ion sensors

Abstract

A sulfur-bridged dibenzimidazolium-based pincer ligand was successfully synthesized and utilized to fabricate fluorescent organic nanoparticles (FONPs) via a simple, water-based re-precipitation method. FONPs exhibited a strong blue fluorescence, and upon interaction with Ag⁺ ions, they efficiently underwent in situ reduction to form Ag@FONPs nanohybrids. These nanohybrids demonstrated excellent chemical and oxidative stability, maintaining over 95% fluorescence intensity after exposure to H₂O₂ and NaCl environments. Ag@FONPs showed outstanding catalytic efficiency, achieving the complete reduction of 4-nitrophenol within 18 minutes and 80% degradation of methyl orange within 10 minutes under light irradiation. Furthermore, the nanohybrids exhibited high selectivity and sensitivity toward azide (N₃⁻) ions. These findings highlight the multifunctional nature of Ag@FONPs, positioning them as robust candidates for applications in environmental catalysis, pollutant degradation, and ion sensing.