Ligand effects on the structure and the electronic optical properties of anionic Au25(SR)18 clusters

Alfredo Tlahuice-Flores, Robert L. Whetten, Miguel Jose-Yacaman

Research output: Contribution to journalArticlepeer-review

137 Scopus citations


This study addresses how ligands module the structure and the electronic optical properties of a large set of the experimentally known anionic thiolate-protected gold clusters, Au25(SR)18 [1-]. Starting from the experimental crystal structure, computational density functional theory calculations reveal that low-polarity R groups do not disturb the Au25S18 framework significantly, such that the inversion symmetry(Ci) of the crystalline state is retained. In the case of p-thiolphenolate ligands, p-SPhX, a major distortion of the Au 25S18 framework, destroys the inversion symmetry, the distortion increasing in the order given X = H, Cl, NO2 and CO 2H. For branched R groups, linking -CH3 or -NH2 groups at the two-position of the phenylethylthiolate ligand, the inversion symmetry is retained and lost, respectively; similarly, the N-acetyl-cysteine ligand also distorts the framework. These results demonstrate a systematic preference of inversion-symmetric versus nonsymmetric framework depending on the ligand-type. The more distorted structures also exhibit significantly reduced HOMO-LUMO gap values and affect the optical absorption spectra accordingly. This study correlates the distortion of the Au25S18 framework with the structure, electronic, and optical properties among the studied clusters.

Original languageEnglish (US)
Pages (from-to)20867-20875
Number of pages9
JournalJournal of Physical Chemistry C
Issue number40
StatePublished - Oct 10 2013
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Energy
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


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