Structural and theoretical basis for ligand exchange on thiolate monolayer protected gold nanoclusters.
J Am Chem Soc
; 134(32): 13316-22, 2012 Aug 15.
Article
em En
| MEDLINE
| ID: mdl-22816317
ABSTRACT
Ligand exchange reactions are widely used for imparting new functionality on or integrating nanoparticles into devices. Thiolate-for-thiolate ligand exchange in monolayer protected gold nanoclusters has been used for over a decade; however, a firm structural basis of this reaction has been lacking. Herein, we present the first single-crystal X-ray structure of a partially exchanged Au(102)(p-MBA)(40)(p-BBT)(4) (p-MBA = para-mercaptobenzoic acid, p-BBT = para-bromobenzene thiol) with p-BBT as the incoming ligand. The crystal structure shows that 2 of the 22 symmetry-unique p-MBA ligand sites are partially exchanged to p-BBT under the initial fast kinetics in a 5 min timescale exchange reaction. Each of these ligand-binding sites is bonded to a different solvent-exposed Au atom, suggesting an associative mechanism for the initial ligand exchange. Density functional theory calculations modeling both thiol and thiolate incoming ligands postulate a mechanistic pathway for thiol-based ligand exchange. The discrete modification of a small set of ligand binding sites suggests Au(102)(p-MBA)(44) as a powerful platform for surface chemical engineering.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Nanopartículas Metálicas
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Ouro
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article