Gold Nanoparticles Supported on Modified Chitosan Oligomers: Stability and Catalytic Performance

This study investigates the synthesis and stabilization of gold nanoparticles (Au‐NPs) ≈20 nm in diameter, using modified chitooligosaccharide (COS) as a biopolymeric matrix, emphasizing their application in catalysis. The modified COS serves as a stabilizing agent for the Au‐NPs, enhancing their catalytic efficiency and the recovery of the catalyst. Structural characterization techniques, including UV‐vis spectroscopy, Fourier‐transform infrared spectroscopy, and transmission electron microscopy, are employed to analyze the polymeric matrices and confirm the successful integration of Au‐NPs. The higher stability of Au‐NPs in P2 is attributed to the rigid imidazole rings, which form a more ordered network than the flexible diimine bonds in P1. The catalytic performance of the Au‐NPs on modified COS is evaluated in the isomerization reaction of sulfamethazine‐azo‐aniline, achieving up to 73% efficiency in the third cycle of reuse. This research highlights the promising role of biopolymer‐based catalysts in advancing sustainable and efficient organic synthesis.