Electronic structure and optical properties of the thiolate-protected Au28(SMe)20 cluster

Stefan Knoppe; Sami Malola; Lauri Lehtovaara; Thomas Bürgi; Hannu Häkkinen

doi:10.1021/jp407494v

Electronic structure and optical properties of the thiolate-protected Au28(SMe)20 cluster

J Phys Chem A. 2013 Oct 10;117(40):10526-33. doi: 10.1021/jp407494v. Epub 2013 Sep 30.

Authors

Stefan Knoppe¹, Sami Malola, Lauri Lehtovaara, Thomas Bürgi, Hannu Häkkinen

Affiliation

¹ Molecular Imaging and Photonics, Department of Chemistry, KU Leuven , Celestijnenlaan 200D, 3001 Heverlee, Belgium.

PMID: 24032562
DOI: 10.1021/jp407494v

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.