Artículo
Surface Chemistry of Thiomalic Acid Adsorption on Planar Gold and Gold Nanoparticles
Azcárate, Julio César
; Floridia Addato, María Alejandra
; Rubert, Aldo Alberto
; Corthey, Gastón
; Kürten Moreno, German S.; Benitez, Guillermo Alfredo
; Zelaya, Maria Eugenia
; Salvarezza, Roberto Carlos
; Fonticelli, Mariano Hernan
Fecha de publicación:
12/02/2014
Editorial:
American Chemical Society
Revista:
Langmuir
ISSN:
0743-7463
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
The self-assembly of thiomalic acid (TMA) on Au(111) and on preformed Au nanoparticles (AuNPs) protected by weak ligands has been studied by X-rayphotoelectron spectroscopy (XPS) and electrochemical techniques. Results show that TMA is adsorbed on the Au(111) surface as thiolate species with a small amount of atomic sulfur (∼10%) and a surface coverage lower than that found for alkanethiols due to steric factors. The amount of atomic sulfur markedly increases when the TMA is adsorbed on AuNPs by the ligand exchange method. We propose that the atomic sulfur is produced as a consequence of C−S bondcleavage, a process that is more favorable at defective sites of the AuNPs surface. The bond scission is also assisted by the presence of the electron-withdrawing carboxy moiety in the α-position relative to the C−S bond. Moreover, the high local concentration of positively charged species increases the stability of the negatively charged leaving group, leading to a higher amount of coadsorbed atomic sulfur. Our results demonstrate that the terminal functionalities of thiols are conditioning factors in the final structure and composition of the adlayers.
Palabras clave:
Nanoparticles
,
Aunp@Tma
,
Xps
,
Tem
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Colecciones
Articulos(CCT - PATAGONIA NORTE)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - PATAGONIA NORTE
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - PATAGONIA NORTE
Citación
Azcárate, Julio César; Floridia Addato, María Alejandra; Rubert, Aldo Alberto; Corthey, Gastón; Kürten Moreno, German S.; et al.; Surface Chemistry of Thiomalic Acid Adsorption on Planar Gold and Gold Nanoparticles; American Chemical Society; Langmuir; 30; 7; 12-2-2014; 1820-1826
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