title: Electronic structure and optical properties of the thiolate-protected Au28(SMe)20 cluster.
abstract: The recently reported crystal structure of the Au28(TBBT)20 cluster (TBBT: p-tert-butylbenzenethiolate) is analyzed with (time-dependent) density functional theory (TD-DFT). Bader charge analysis reveals a novel trimeric Au3(SR)4 binding motif. The cluster can be formulated as Au14(Au2(SR)3)4(Au3(SR)4)2. The electronic structure of the Au14(6+) core and the ligand-protected cluster were analyzed, and their stability can be explained by formation of distorted eight-electron superatoms. Optical absorption and circular dichroism (CD) spectra were calculated and compared to the experiment. Assignment of handedness of the intrinsically chiral cluster is possible.
authors.affiliation: Molecular Imaging and Photonics, Department of Chemistry, KU Leuven , Celestijnenlaan 200D, 3001 Heverlee, Belgium.
authors.forename: Stefan
authors.initials: S
authors.lastname: Knoppe
authors.forename: Sami
authors.initials: S
authors.lastname: Malola
authors.forename: Lauri
authors.initials: L
authors.lastname: Lehtovaara
authors.forename: Thomas
authors.initials: T
authors.lastname: Bürgi
authors.forename: Hannu
authors.initials: H
authors.lastname: Häkkinen