The Structure and Bonding Properties of Tiopronin-protected Silver Nanoparticles as Studied by X-ray Absorption Spectroscopy at Ag K-, Ag L3-, and S K-edges

Thiolate-protected Ag nanoparticles (NPs) exhibit interesting optical and biomedical properties which may lead to various sensing, diagnostic and therapeutic applications. Therefore, understanding structure-property relationships of Ag NPs is of great interest. 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 some thiolate-stabilized Ag NPs. Comparing 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 L3-, 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. Key words: Silver-thiolate nanoparticles, X-ray absorption spectroscopy, local structure, bonding propertyThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author