The structure and bonding properties of tiopronin-protected silver nanoparticles as studied by X-ray absorption spectroscopy

Abstract

Thiolate-protected Ag nanoparticles (NPs) exhibit interesting physical and chemical properties which may lead to various sensing, diagnostic, and therapeutic applications. Further, understanding structure-property relationships of Ag NPs is of great interest in order to optimize their application. Herein, we used TEM, UV-vis, and a series of synchrotron X-ray spectroscopy techniques to probe the local structure and chemical bonding properties of thiolate-stabilized Ag NPs. Compared with other Ag nanostructures prepared under slightly modified conditions, the Ag NPs were found to have pronounced structural changes, which led to immensely different optical properties. Notably, the NPs were also found to have similar surface structure to recently elucidated Ag nanoclusters prepared with different thiolates. These findings suggest that the NP structure and optical properties can be sensitively tailored by controlling the synthetic conditions. The multi-element, multi-core excitation approach (i.e., Ag K-, Ag L 3 -, and S K-edges) employed in the X-ray absorption spectroscopy measurements was also demonstrated as an effective tool to uncover the NP structure from both the metal core and ligand shell perspectives.

Activation of atomically precise silver clusters on carbon supports for styrene oxidation reactions

“…Attempts to use multiple Ag-Ag rst shells in tting were unsuccessful as the data quality was not sufficient for such a detailed analysis. 18,59 Nevertheless, the data suggests successful immobilization of Ag 25 L 18 À clusters onto carbon supports without compromising their structural integrity. 39 In summary, XPS and XAS data of as-prepared Ag 25 /carbon catalysts suggest that the structural changes in activated Ag 25 / carbon samples can be solely due to calcination which causes removal of protecting ligands from Ag 25 L 18 À clusters.…”

Selection of chromatographic separation conditions for reliable monitoring of the transformation of AgNPs/Ag(i) species by HPLC-ICP-MS in surface water and green algae cells

“…This was probably due to gradual formation of complexes between Ag( i ) and tiopronin molecules. Padmos et al 26 showed that complexes with more than one Ag atom per S can be formed with some low-molecular-weight thiols, such as tiopronin.…”

“…Some authors suggest that the thiolate groups of tiopronin cause suldation at AgNP surfaces, which was already used for protection of silver nanoparticles. 26,27 Therefore, the chosen composition of the mobile phase was: 10 mM SDS + 2 mM citrate buffer + 2 mM tiopronin. As can be seen in Fig.…”