Gallou, Fabrice (2024) Micelle-Dependent Spontaneous Formation of Gold(I) in Nanodendritic Chloride-Bridged Particles with Catalytic Activity for Cyclization of Alkynylanilines in an Aqueous Environment. ACS Catalysis, 14 (20). pp. 15645-15653.

Abstract

A novel proline-based amphiphile featuring a thiourea functional group has been synthesized for the purpose of controlled
reduction of Au(III) to Au(I) and subsequent stabilization of the resulting nanomaterial. This study elucidates the significant
role played by the newly developed amphiphile, along with chloride ions, in imparting a dendritic morphology to the resulting nanomaterial.Such morphology is pivotal for the catalytic activity of Au(I), as demonstrated in the cyclization reaction of alkynylanilines, conducted in water as a benign reaction medium. The structural characterization of the nanomaterial revealed intriguing associations between dendrimers and nanomicelles, as observed through cryogenic transmission electron microscopy. Further insights into the structures of dendritic Au are provided by scanning transmission electron microscopy-high angle annular dark field imaging and high-resolution transmission electron microscopy imaging. Additionally, spectroscopic analyses, including X-ray photoelectron and X-ray absorption spectroscopy, corroborate the presence of Au in the +1 oxidation state within the dendritic nanomaterial. The metalamphiphile binding is further supported by X-ray absorption fine structure fitting. Control cyclic voltammetry analysis confirms the amphiphile's mediation of Au(III) to Au(I) reduction. The dendritic morphology is significantly influenced by nucleophilic bromide ions, which disrupt bridging linkages formed by chloride ions. Under such conditions, the catalytic activity is adversely affected.

Item Type:	Article
Date Deposited:	17 Dec 2024 00:45
Last Modified:	17 Dec 2024 00:45
URI:	https://oak.novartis.com/id/eprint/53963