Multidentate Triazole Coordination Unlocks Color-Tunable Plasmonic Gold Nanoparticle Films to Achieve High Catalytic...

Gold nanoparticles (AuNPs) have shown considerable promise in catalysis and optoelectronics; however, their inherent tendency to aggregate and their limited processability hinder practical applications. Herein, we present a systematic ligand-engineering strategy for tailoring the hierarchical assembly of AuNPs into functional hybrid films, employing four structurally related 1,2,4-triazole multidentate molecules of increasing coordination complexity under a unified solution compounding-vacuum filtration-thermal curing route. The results demonstrate that the type, number, and interplay of coordinating functional groups on the triazole scaffold govern the assembly architecture and interparticle plasmonic coupling, enabling a ligand-programmed color-tunable effect from wine-red through purple and blue to gray-brown. Among the series, the C₂H₆N₆S -modified film-bearing thiol (-SH), amine (-NH₂), and hydrazide (-NHNH₂) groups on a single molecular scaffold-delivers the highest catalytic activity for 2-nitrophenol reduction, achieving complete conversion within 14 min and maintaining over 95% conversion after nine consecutive cycles. Combined XPS, XRD, and SEM analyses attribute this performance to the multidentate coordination of C₂H₆N₆S, which simultaneously enables dense particle packing, favorable electronic modulation of the Au surface, and robust structural stability. This work establishes a structure-property framework linking ligand multifunctionality to thin-film performance, and provides a rational design principle for engineering AuNP-based hybrid materials with tailored.