A unified view of ligand-protected gold clusters as superatom complexes

Michael Walter, Jaakko Akola, Olga Lopez-Acevedo, Pablo D. Jadzinsky, Guillermo Calero, Christopher J. Ackerson, Robert L. Whetten, Henrik Groenbeck, Hannu Hakkinen*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chemistry of nanomaterials. Factors driving the thermodynamic stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles protected by thiolate (SR) or phosphine and halide (PR3, X) ligands. The picture has emerged from analysis of large-scale density functional theory calculations of structurally characterized compounds, namely Au-102(SR)(44), Au-39(PR3)(14)X-6(-), Au-11(PR3)(7)X-3, and Au-13(PR3)(10)X-2(3+), where X is either a halogen or a thiolate. Attributable to a compact, symmetric core and complete steric protection, each compound has a filled spherical electronic shell and a major energy gap to unoccupied states. Consequently, the exceptional stability is best described by a "noble-gas superatom" analogy. The explanatory power of this concept is shown by its application to many monomeric and oligomeric compounds of precisely known composition and structure, and its predictive power is indicated through suggestions offered for a series of anomalously stable cluster compositions which are still awaiting a precise structure determination.

Original languageEnglish
Pages (from-to)9157-9162
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume105
Issue number27
DOIs
Publication statusPublished - 8 Jul 2008
MoE publication typeA1 Journal article-refereed

Keywords

  • density functional theory
  • monolayer-protected cluster
  • STRUCTURAL EVOLUTION
  • AU(111) SURFACE
  • METAL-CLUSTERS
  • NANOPARTICLES
  • MOLECULES
  • CHEMISTRY
  • THIOLS
  • NANOTECHNOLOGY
  • NANOCLUSTERS
  • NANOCRYSTAL

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