From the Superatom Model to a Diverse Array of Super-Elements: A Systematic Study of Dopant Influence on the Electronic Structure of Thiolate-Protected Gold Clusters

• Published in: Chemphyschem 2016-10, Vol.17 (20), p.3237-3244
• Main Authors: Schacht, Julia, Gaston, Nicola
• Format: Article
• Language: English
• Subjects: density functional calculations; gold nanoclusters; nanomaterials; single-atom doping; superatom
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201600684

The electronic properties of doped thiolate‐protected gold clusters are often referred to as tunable, but their study to date, conducted at different levels of theory, does not allow a systematic evaluation of this claim. Here, using density functional theory, the applicability of the superatomic model to these clusters is critically evaluated, and related to the degree of structural distortion and electronic inhomogeneity in the differently doped clusters, with dopant atoms Pd, Pt, Cu, and Ag. The effect of electron number is systematically evaluated by varying the charge on the overall cluster, and the nominal number of delocalized electrons, employed in the superatomic model, is compared to the numbers obtained from Bader analysis of individual atomic charges. We find that the superatomic model is highly applicable to all of these clusters, and is able to predict and explain the changing electronic structure as a function of charge. However, significant perturbations of the model arise due to doping, due to distortions of the core structure of the Au13[RS(AuSR)2]6− cluster. In addition, analysis of the electronic structure indicates that the superatomic character is distributed further across the ligand shell in the case of the doped clusters, which may have implications for the self‐assembly of these clusters into materials. The prediction of appropriate clusters for such superatomic solids relies critically on such quantitative analysis of the tunability of the electronic structure. The effects of microdoping: The tunability of doped thiolate‐protected gold clusters is systematically investigated by means of density functional theory. The superatomic model is evaluated for its applicability, by comparing structural distortion and electronic inhomogeneity for Pd‐, Pt‐, Cu‐ and Ag‐doped clusters.