Synthesis of Chiral, Crystalline Au-Nanoflower Catalyst Assisting Conversion of Rhodamine-B to Rhodamine-110 and a Single-Step, One-Pot, Eco-Friendly Reduction of Nitroarenes

Chiral, multipetal gold nanoflowers (AuNFs) with crystalline tips were synthesized in high yield through the reduction of HAuCl4 in water in the presence of preformed coresatellite Ag nanoparticle (AgNP) seeds. High-resolution transmission electron microscopic (HRTEM) images and tomography reveal the actual crystallographic and 3-dimensional structural profile of the AuNFs. In a first demonstration of this kind, a Hg2+/AuNF combination was shown to catalyze the direct transformation of rhodamine-B to rhodamine-110 in water. The AuNFs were also shown to catalyze reduction of nitroarenes to its corresponding aminoarene with similar to 90% conversion efficiency by a single-step, one-pot, eco-friendly protocol. There are numerous opportunities for using these unique AuNFs in catalysis, sensing, imaging, drug delivery, and opto-photonics.