Synthesis of gold nanoparticles and nanoclusters in a supramolecular gel and their applications in catalytic reduction of p-nitrophenol to p-aminophenol and Hg(ii) sensing

Abstract

A new series of urea/amide functionalized bis-pyridyl compounds was found to give gels in various solvent systems, viz. DMF–water, DMSO–water, ethylene glycol–water and nitrobenzene. On sprinkling solid HAuCl₄·xH₂O, in these gels, small gold nano-clusters/gold nano-particles (AuNCs/AuNPs) were found to form, without the use of any exogenous reducing agent. The AuNPs embedded gels were capable of catalyzing the reduction of p-nitrophenol to p-aminophenol and that too without any external reducing agent like NaBH₄. The small gold nanoclusters formed in the nitrobenzene gel of the gelators were fluorescent and this property has been exploited for sensing of Hg(II).