Mild homogeneous synthesis of gold nanoparticles through the epoxide route: kinetics, mechanisms and related one‐pot composites

OESTREICHER, VÍCTOR; HUCK-IRIART, CRISTIÁN; SOLER-ILLIA, GALO; ANGELOMÉ, PAULA C.; JOBBAGY, MATIAS

CHEMISTRY-A EUROPEAN JOURNAL

WILEY-V C H VERLAG GMBH

Año: 2020

0947-6539

A new one‐pot room temperature homogeneous methodology to obtain Au nanoparticles (AuNP), based on the epoxide route is presented. The proposed method takes advantage of the homogenous generation of OH? moieties driven by epoxide ring‐opening, mediated by chloride nucleophilic attack. Once reached an alkaline condition, the reducing media allows the quantitative formation of AuNP under a well‐defined kinetic control. A stabilizing agent, as PVP or CTAC, is required to maintain the AuNP stable; meanwhile their presence dramatically affects the reduction kinetics and pathway, as demonstrated by the evolution of the UV‐Vis spectra, SAXS patterns and pH along the reaction. In the presence of PVP‐10k, nanogold spheroids are obtained following a similar reduction mechanism as the observed for control experiments in the absence of PVP. However, If CTAC is employed, a stable complex with Au(III) is formed, leading to a different reaction pathway and resulting in ellipsoidal‐like shaped AuNP. Moreover, the proposed methodology allows stabilize the growing AuNP, by coupling their formation with non‐alkoxidic sol‐gel reactions, leading to nanocomposite gels with embedded metallic nanoparticles. The epoxide route thus offers a versatile scenario for the one‐pot preparation of novel metal nanoparticles‐inorganic/hybrid matrices nanocomposites with valuable optical properties.