On the ligand exchange, redox, and disproportionation processes of tetrachloroaurate in the presence of a pyridine derivative

Simon, Sajna; Clarke, Osai J. R.; Burgess, Ian J.

doi:10.1016/j.electacta.2020.137213

Cited by 2 publications

(1 citation statement)

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“…−1.5 V (SCE) based on the type of the complexing agents . Considering the previous studies regarding the effect of the ligand exchange processes on the reduction potential of gold ions, the ligand exchange processes of Au I Cl 2 – in the presence of NMP can be considered as a reasonable factor that changes the reduction potential of Au I species and creates a thermodynamical barrier to reducing Au I Cl 2 – into gold clusters by NMP or through a spontaneous disproportionation. This point can be mentioned in the parenthesis that creating a sustainable Au I Cl 2 – in NMP solution, as a widely used organic medium, is one of the remarkable points of this study due to the importance of Au I chloride species as reactants and intermediates in various chemical sciences and engineering processes …”

Section: Resultsmentioning

confidence: 99%

N-Methyl-2-pyrrolidone as a Reaction Medium for Gold(III)-Ion Reduction and Star-like Gold Nanostructure Formation

et al. 2022

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The efficiency of a wet chemical route to synthesize gold nanostructures with tunable size and shape significantly depends on the applied solvent and the interaction of solvent molecules with other species such as gold ions. The ability of the organic solvent N -methyl-2-pyrrolidone (NMP) as a suitable medium for application in star-like gold nanostructure (AuNS) synthesis with a tunable morphology at ambient conditions has been investigated. The time-dependent analysis of the UV–vis absorption spectra of Au III Cl 4 – in a pure NMP solution illustrates the role of NMP as simultaneous complexing and reducing agents. Kinetic studies indicate that Au III Cl 4 – in NMP solution is reduced to Au I Cl 2 – , with no need to use another reducing agent, any external energy sources, or solvent pretreatment. This is because Au I species stay stable in this solution unless poly(vinylpyrrolidone) (PVP) catalyzes their disproportionation. Morphological studies by transmission electron microscopy (TEM) specify the high-yield synthesis of AuNS with monocrystalline spikes in a concentrated NMP solution by PVP. This study illustrates that the presence of seeds, as another agent to catalyze the disproportionation of Au I species, makes it possible to synthesize AuNS in varying concentrations of PVP in this medium. The role of PVP concentration and the presence of seeds in the formation kinetics, morphology, and optical properties is systematically discussed. The results achieved through this study develop a straightforward and safe procedure for AuNS synthesis in high yield in a water-miscible organic polar solvent with tunable morphology and optical properties. Considering the high capability of NMP to dissolve various types of polymers and hydrophobic ligands, synthesizing AuNS in this solvent opens a window to a practical and easy way to fabricate gold-based nanomaterials with fascinating optical properties.

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Section: Resultsmentioning

confidence: 99%