Assembling Au₄ Tetrahedra to 2D and 3D Superatomic Crystals Based on Superatomic-Network Model

Abstract

Thiolate-protected gold nanoclusters (denoted as Au m (SR) n or Au n L m ) have received extensive attention both experimentally and theoretically. Understanding the growth mode of the Au 4 unit in Au m (SR) n is of great significance for experimental synthesis and the search for new gold clusters. In this work, we first build six clusters of Au 7 (AuCl 2 ) 3 , Au 12 (AuCl 2 ) 4 , Au 16 (AuCl 2 ) 6 , Au 22 (AuCl 2 ) 6 , and Au 30 (AuCl 2 ) 6 with the Au 4 unit as the basic building blocks. Density functional theory (DFT) calculations show that these newly designed clusters have high structural and electronic stabilities. Based on chemical bonding analysis, the electronic structures of these clusters follow the superatom network (SAN) model. Inspired by the cluster structures, we further predicted an Au 4 two-dimensional (2D) monolayer and a three-dimensional (3D) crystal using graphene and diamond as templates, respectively. The computational results demonstrate that the two structures have high dynamic, thermal, and mechanical stabilities, and both structures exhibit metallic properties according to the band structures calculated at the HSE06 level. The chemical bonding analysis by the solid-state natural density partitioning (SSAdNDP) method indicates that they are superatomic crystals assembled by two electron Au 4 – superatoms. With this construction strategy, the new bonding pattern and properties of Au n L m are studied and the structure types of gold are enriched.

[Ba4@Sn56]36– as a Main-Group Second-Order Superatom. Interpenetrated Dodecahedrons as a Three-Dimensional Cluster-of-Clusters Structure

“…A three-dimensional array in a tetrahedral fashion enables the interaction between superatomic shells centered at each constituent unit. Similarly to tetrahedral clusters composed of atoms, like Au 4 2+ and P 4 , − shells centered at the vertex are combined to give rise to superatomic shells. In Au 4 2+ and P 4 clusters, four n s -atomic shells result in a 1S1P superatomic shell structure featuring a total bonding (1S) and three formally nonbonding combinations (1P), with tangential n p -atomic shells giving rise to 1D and part of the 1F superatomic shells.…”

On the halide aggregation into the [Au4(PPh3)4]4+ cluster core. Insights from structural, optical and interaction energy analysis in [(Ph3PAu)4X2]2+ and [(Ph3PAu)4X]3+ species (X = Cl−, Br−, I−)

“…2). To evaluate their anion binding characteristics, in addition to [(Ph In contrast to superatomic Au 4 clusters involving two cluster electrons in a 1S 2 superatomic electronic configuration, or more electrons, [96][97][98][99] usually featuring a 6s-Au based lowest unoccupied orbital (LUMO), the [(Ph 3 PAu) 4 X 2 ] 2+ and [(Ph 3 PAu) 4 X] 3+ clusters involve mixed ligand/5d-Au/6s-Au/X frontier orbitals, accounting for the electron deficient character of the (Ph 3 PAu) 4 4+ cluster core. The resulting frontier orbital gap between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO gap) amounts to about B3.0 eV (av.)…”