A Simple One-Step Ultrasonic Route To Synthesize Antioxidant Molecules and Fluorescent Nanoparticles from Phenol and Phenol-Like Molecules

Fluorescent oligomeric structures were synthesized from the phenolic moieties by a simple one-step sonochemical approach without the use of enzymes, metal catalyst, or other toxic reagents. The formation of phenol dimers, trimers, and oligomers was confirmed by absorption spectroscopy, fluorescence spectroscopy, HPLC, and mass spectroscopy. We have demonstrated that the cavitation bubble surface acted as a catalytic binding site to generate such oligomers, and the ultrasonic frequency, concentration, and other physicochemical properties (surface activity) of phenolic building blocks can affect the formation of these oligomers. The sonochemically produced phenolic oligomers showed antioxidant activity which was determined by DPPH assay. The study suggests that acoustic cavitation could promote polymerization of simple phenolic molecules to generate bioactive oligomers and nanostructures with varying functional properties.