title: Polydisperse composition of mixed monolayer-protected, spin-labeled Au nanoparticles.
abstract: Using EPR spectroscopy and spin-labeled ligands, we have studied product distribution in the ligand exchange reactions of Au nanoparticles. When the incoming ligand was used in excess, the exchanged nanoparticles had uniform composition of the organic shell. Preparative GPC was employed to fractionate these materials according to the diameter of the Au core, as confirmed by TEM, UV, and EPR measurements. When the exchange reaction was carried out with less than a stoichiometric amount of the incoming ligand, nanoparticles with polydisperse composition of the organic shell were formed. This was established by the EPR analysis of the exchange reaction mixtures following their GPC fractionation. The GPC separation of these mixtures is controlled by both Au core size and shell composition.
authors.affiliation: Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
authors.forename: Helen
authors.initials: H
authors.lastname: Wellsted
authors.forename: Esther
authors.initials: E
authors.lastname: Sitsen
authors.forename: Agneta
authors.initials: A
authors.lastname: Caragheorgheopol
authors.forename: Victor
authors.initials: V
authors.lastname: Chechik