Abstract
The total structure determination of the Au36(SPh-tBu) 24 cluster presented herein and the theoretical insights into its bonding and electronic structure that we gained, have certain valuable implications for future investigations. First, our findings show that the structures and stability of nanoclusters are determined by a balance between maximization of the metal (gold) cohesive energy and the electronic effect of the conjugated thiolate. Along with this is our experimental (Supporting Information, Figure S2) and theoretical findings of a large (approximately 1.7 eV) HOMO-LUMO energy gap conferring to the cluster extreme stability, and originating from the (superatom) shell-structure organization of the electronic energy levels of the cluster; the occupancies of the shells and their degeneracies are both determined by the metal component of the cluster as well as by its interactions with the protecting thiolates. Second, the finding that a cluster as small as Au36(SPh-tBu)24 can have a nanocrystalline FCC core, provides a strong impetus for reexamination of the ordering and transitions between various structural motifs appearing along the size-dependent evolution of nanocluster structures. Third, this work shows that the bridge-bonding motif of thiolates on gold particles is an important addition to the previously observed monomeric and dimeric (and the recently theoretically proposed trimeric) staple motifs, as surface protectors for Aun (SR)m nanoclusters. This finding may have implications for the still controversial case of selfassembled monolayers (SAM) on bulk gold surfaces.
Original language | English (US) |
---|---|
Pages (from-to) | 13114-13118 |
Number of pages | 5 |
Journal | Angewandte Chemie - International Edition |
Volume | 51 |
Issue number | 52 |
DOIs | |
State | Published - Dec 21 2012 |
Externally published | Yes |
Keywords
- Cluster compounds
- Face-centered cubic
- Gold
- Nanostructures
- Tetrahedral structures
ASJC Scopus subject areas
- Catalysis
- General Chemistry