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Quantified Binding Scale of Competing Ligands at the Surface of Gold Nanoparticles: The Role of Entropy and Intermolecular Forces
Author(s) -
Goldmann Claire,
Ribot François,
Peiretti Leonardo F.,
Quaino Paola,
Tielens Frederik,
Sanchez Clément,
Chanéac Corinne,
Portehault David
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201604028
Subject(s) - intermolecular force , nanoparticle , ligand (biochemistry) , bifunctional , colloidal gold , monolayer , nanotechnology , density functional theory , amide , chemistry , chemical physics , entropy (arrow of time) , materials science , molecule , computational chemistry , organic chemistry , thermodynamics , catalysis , biochemistry , receptor , physics
A basic understanding of the driving forces for the formation of multiligand coronas or self‐assembled monolayers over metal nanoparticles is mandatory to control and predict the properties of ligand‐protected nanoparticles. Herein, 1 H nuclear magnetic resonance experiments and advanced density functional theory (DFT) modeling are combined to highlight the key parameters defining the efficiency of ligand exchange on dispersed gold nanoparticles. The compositions of the surface and of the liquid reaction medium are quantitatively correlated for bifunctional gold nanoparticles protected by a range of competing thiols, including an alkylthiol, arylthiols of varying chain length, thiols functionalized by ethyleneglycol units, and amide groups. These partitions are used to build scales that quantify the ability of a ligand to exchange dodecanethiol. Such scales can be used to target a specific surface composition by choosing the right exchange conditions (ligand ratio, concentrations, and particle size). In the specific case of arylthiols, the exchange ability scale is exploited with the help of DFT modeling to unveil the roles of intermolecular forces and entropic effects in driving ligand exchange. It is finally suggested that similar considerations may apply to other ligands and to direct biligand synthesis.