title: Ligand symmetry-equivalence on thiolate protected gold nanoclusters determined by NMR spectroscopy.
abstract: The Au(144)(SR)(60) nanocluster has been a subject of structural conjecture since its initial description over a decade ago as a 29 kDa compound, yet a decisive empirical structure is elusive. Herein we show that (1)H NMR spectroscopy can provide a detailed view of ligand-layer equivalence for thiolate protected gold nanoclusters. We show that Au(25)(SR)(18), Au(38)(SR)(24) and Au(102)(SR)(44) nanoclusters have (1)H NMR spectra where the number of distinct chemical environments for the R-groups is equivalent to the number of symmetry environments of the sulfur headgroups, which anchor each ligand. We also show that the Au(144)(SR)(60)(1)H NMR spectrum is consistent with a previously published DFT-derived structural model for Au(144)(SR)(60). We suggest that this analysis may be extended to other structurally obscure nanoclusters, such as a ∼59 kDa compound for which we observe up to four symmetry environments.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, CO 80521, USA.
authors.forename: O Andrea
authors.initials: OA
authors.lastname: Wong
authors.forename: Christine L
authors.initials: CL
authors.lastname: Heinecke
authors.forename: Ashli R
authors.initials: AR
authors.lastname: Simone
authors.forename: Robert L
authors.initials: RL
authors.lastname: Whetten
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ackerson