Chirality and Electronic Structure of the Thiolate-Protected Au-38 Nanocluster

Olga Lopez-Acevedo, Hironori Tsunoyama, Tatsuya Tsukuda, Hannu Hakkinen, Christine M. Aikens*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Structural, electronic, and optical properties of the thiolate-protected Au-38(SR)(24) cluster are studied by density-functional theory computations (R = CH3 and R = C6H13) and by powder X-ray crystallography (R = C12H25). A low-energy structure which can be written as Au-23@(Au(SR)(2))(3)(Au-2(SR)(3))(6) having a bi-icosahedral core and a chiral arrangement of the protecting gold thiolate Au,,(SR), units yields an excellent match between the computed (for R = C6H13) and measured (for R = C12H25) powder X-ray diffraction function. We interpret in detail the electronic structure of the Au-23 core by using a particle-in-a-cylinder model. Although the alkane thiolate ligands are achiral, the chiral structure of the ligand layer yields strong circular dichroism (CD) in the excitations below 2.2 eV for Au-38(SCH3)(24). Our calculated CD spectrum is in quantitative agreement with the previously measured low-energy CD signal of glutathione-protected Au-38(SG)(24). Our study demonstrates a new mechanism for the strong chiral response of thiolate-protected gold clusters with achiral metal cores and ligands.

Original languageEnglish
Pages (from-to)8210-8218
Number of pages9
JournalJournal of the American Chemical Society
Volume132
Issue number23
DOIs
Publication statusPublished - 16 Jun 2010
MoE publication typeA1 Journal article-refereed

Keywords

  • NANOCRYSTAL GOLD MOLECULES
  • OPTICAL-ABSORPTION SPECTRA
  • DENSITY-FUNCTIONAL THEORY
  • SIMPLE METAL-CLUSTERS
  • CIRCULAR-DICHROISM
  • CATALYTIC-ACTIVITY
  • AEROBIC OXIDATION
  • CRYSTAL-STRUCTURE
  • SODIUM CLUSTERS
  • SHELL STRUCTURE

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