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

Area of Science:

• Materials Science
• Computational Chemistry
• Nanotechnology

Background:

• Thiolate-protected gold nanoclusters (Au(SR) or AuL) are of significant experimental and theoretical interest.
• Understanding the growth of the Au₄ unit is crucial for synthesizing new gold clusters.

Purpose of the Study:

• To investigate the structural and electronic properties of novel gold clusters built from Au₄ units.
• To predict and analyze the stability and properties of 2D and 3D gold structures templated on graphene and diamond.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to design and analyze six gold clusters.
• Chemical bonding analysis, including the superatom network (SAN) model and solid-state natural density partitioning (SSAdNDP), was used.
• Band structures were calculated at the HSE06 level to determine electronic properties.

Main Results:

• Six novel gold clusters (Au₇(AuCl₂)₃ to Au₃₀(AuCl₂)₆) were designed, exhibiting high structural and electronic stability.
• The electronic structures of these clusters conform to the superatom network (SAN) model.
• Predicted 2D monolayer and 3D crystal structures of Au₄ exhibit high dynamic, thermal, and mechanical stability, along with metallic properties.
• These superatomic crystals are composed of two-electron Au₄⁻ superatoms.

Conclusions:

• The Au₄ unit serves as a fundamental building block for stable gold nanoclusters and extended structures.
• The study reveals a new bonding pattern in gold clusters and enriches the known types of gold structures.
• Computational methods provide a pathway for designing and understanding novel gold-based materials.