Au Nanostructures with Controlled Morphology, Biosynthesized from Garcinia cowa Fruit Extract, and Their Use in Microwave‐Mediated Bisindole Synthesis

Abstract

Au nanoparticles (NPs) of controlled morphology have been synthesised through an eco-friendly biogenic method utilizing the aqueous fruit extract of Garcinia cowa at room temperature. The bio extract executes dual role of reducing agent and stabilizing agent to add excellent stability to the synthesized colloidal Au NPs. The variation of particle size and morphology of Au nanostructures with respect to the quantitative part of the bio-extract were studied. After microscopic and spectroscopic characterization, further application of the Au NPs synthesized via green method in the preparation of complex organic molecules was studied. The Au NPs were employed as homogeneous catalyst in coupling of substituted indole and aromatic aldehydes to yield bisindolylmethanes, which are known precursors of anti-cancer bioactive molecules. In addition, microwave irradiation makes the coupling reaction more sustainable with very short reaction time of 40 secs.