NMR Characterization of Ligand Binding and Exchange Dynamics in Triphenylphosphine-Capped Gold Nanoparticles
| Autor: | Herbert Zimmermann, Jeffery L. Yarger, Virgil C. Solomon, Ramesh Sharma, Samrat A. Amin, Daniel A. Buttry, Gregory P. Holland, Steven Schiffenhaus |
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| Rok vydání: | 2009 |
| Předmět: |
Analytical chemistry
Nanoparticle Resonance (chemistry) Ligand (biochemistry) Surfaces Coatings and Films Electronic Optical and Magnetic Materials Characterization (materials science) chemistry.chemical_compound Crystallography General Energy Reaction rate constant chemistry Colloidal gold Physical and Theoretical Chemistry Triphenylphosphine |
| Zdroj: | The Journal of Physical Chemistry C |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | Triphenylphosphine (PPh3)-capped 1.8 nm diameter gold nanoparticles (AuNPs) are characterized by a combination of 1H, 2H, and 31P solution- and solid-state NMR. The 31P{1H} NMR resonance associated with the surface-bound PPh3 is clearly identified and is present as a broad peak centered at 56 ppm. 31P and 1H hole burning NMR experiments show that the line broadening associated with the surface-bound PPh3 is primarily due to a variety of different chemical shift environments at the surface of the nanoparticles. The surface bound PPh3 can be displaced with either d15-PPh3 or Au(d15-PPh3)Cl in CD2Cl2 solution. In both cases, exchange results in loss of Au(PPh3)Cl from the nanoparticle surface, with no evidence for loss of the PPh3 ligand alone. Solution-state NMR was used to determine the room temperature rate constants for these exchange processes, with values of 0.17 and 0.20 min-1, respectively. Thus, essentially the same rate is observed for displacement of Au(PPh3)Cl from the surface with either d15-PPh3 or Au(d15-PPh3)Cl. The observed 31P chemical shift of surface-bound PPh3 is consistent with mixed valence Au(0) and Au(I) at the nanoparticle surfaces, suggesting the presence of surface-bound Au complexes. |
| Databáze: | OpenAIRE |
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