Atomic Sulfur Formation Mechanism on 3‑Mercaptopropanoic Acid Derivative Self-Assembled Monolayers: Understanding the C–SBond Cleavage

Self-assembled monolayers (SAMs) of ω-carboxylic acid thiols are very important in the surface modification of metals, especially on gold surfaces. Indeed, the 3-mercaptopropanoic acid (MPA) and its ester or amide derivatives are widely used for SAM-based sensor design. It was already shown that MPA...

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Detalles Bibliográficos
Autores principales: Azcárate, Julio César, Aagaard, Natalia A., Zampieri, Guillermo, Zelaya, Eugenia, Fonticelli, Mariano Hernán
Formato: Articulo
Lenguaje:Inglés
Publicado: 2019
Materias:
Química
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/123417
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-123417
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Química
spellingShingle Química
Azcárate, Julio César
Aagaard, Natalia A.
Zampieri, Guillermo
Zelaya, Eugenia
Fonticelli, Mariano Hernán
Atomic Sulfur Formation Mechanism on 3‑Mercaptopropanoic Acid Derivative Self-Assembled Monolayers: Understanding the C–SBond Cleavage
topic_facet Química
description Self-assembled monolayers (SAMs) of ω-carboxylic acid thiols are very important in the surface modification of metals, especially on gold surfaces. Indeed, the 3-mercaptopropanoic acid (MPA) and its ester or amide derivatives are widely used for SAM-based sensor design. It was already shown that MPA does not suffer C−S bond scission when adsorbed on Au. On the other hand, in this work we demonstrate that its simplest derivative, methyl 3-mercapto propionate (Me-MPA), is prone to form significant amounts of atomic sulfur when adsorbed on Au. The MPA derivatives are more sensible than MPA itself to alkaline solutions, and its SAM-based sensors will rapidly degrade given atomic sulfur. In this work, we study the simplest MPA derivative Me-MPA SAMs on preferentially oriented Au(111) surfaces by XPS and electrochemical measurements. It was found that the desulfuration of Me-MPA depends on its preparation conditions (grown from ethanol or toluene solution) and on its post-treatment with alkaline solution. In order to explain the S−C bond scission on Me-MPA SAMs, we discuss different reaction mechanisms. We concluded that the reaction mechanism involves an E1cB elimination pathway (β-elimination). This reaction mechanism also explains the desulfuration behavior of other important related molecules like L-cysteine and glutathione.
format Articulo
Articulo
author Azcárate, Julio César
Aagaard, Natalia A.
Zampieri, Guillermo
Zelaya, Eugenia
Fonticelli, Mariano Hernán
author_facet Azcárate, Julio César
Aagaard, Natalia A.
Zampieri, Guillermo
Zelaya, Eugenia
Fonticelli, Mariano Hernán
author_sort Azcárate, Julio César
title Atomic Sulfur Formation Mechanism on 3‑Mercaptopropanoic Acid Derivative Self-Assembled Monolayers: Understanding the C–SBond Cleavage
title_short Atomic Sulfur Formation Mechanism on 3‑Mercaptopropanoic Acid Derivative Self-Assembled Monolayers: Understanding the C–SBond Cleavage
title_full Atomic Sulfur Formation Mechanism on 3‑Mercaptopropanoic Acid Derivative Self-Assembled Monolayers: Understanding the C–SBond Cleavage
title_fullStr Atomic Sulfur Formation Mechanism on 3‑Mercaptopropanoic Acid Derivative Self-Assembled Monolayers: Understanding the C–SBond Cleavage
title_full_unstemmed Atomic Sulfur Formation Mechanism on 3‑Mercaptopropanoic Acid Derivative Self-Assembled Monolayers: Understanding the C–SBond Cleavage
title_sort atomic sulfur formation mechanism on 3‑mercaptopropanoic acid derivative self-assembled monolayers: understanding the c–sbond cleavage
publishDate 2019
url http://sedici.unlp.edu.ar/handle/10915/123417
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