Keplerate Ag₁₉₂ Cluster with 6 Silver and 14 Chalcogenide Octahedral and Tetrahedral Shells.

Area of Science:

• Materials Science
• Inorganic Chemistry
• Nanotechnology

Background:

• Concentric silver shell structures are rare, limiting the study of complex silver clusters.
• Understanding the self-assembly and coordination chemistry of multi-shell silver clusters is crucial for novel material development.

Purpose of the Study:

• To synthesize and characterize a novel, highly symmetric silver chalcogenide cluster (SCC) with multiple concentric shells.
• To elucidate the coordination chemistry mechanism responsible for the stability of these complex structures.

Main Methods:

• Self-assembly of silver chalcogenide cluster (SCC) precursors.
• Crystallization and structural characterization using X-ray diffraction.
• Analysis of polyhedral symmetry and coordination environments.

Main Results:

• Successfully synthesized and crystallized SD/Ag192a, a silver chalcogenide cluster (SCC) with 192 silver cations in 6 shells and 136 anionic groups in 14 shells.
• The cluster exhibits 20 concentric shells, predominantly Platonic or Archimedean solids with octahedral or tetrahedral symmetry, identifying it as a Keplerate.
• A rhombic dodecahedron supershell acts as a keystone, with Ag+ ions and anionic groups occupying interstitial compartments, explaining the cluster's stability.

Conclusions:

• The study presents a novel Keplerate silver chalcogenide cluster (SCC) with unprecedented structural complexity.
• The findings reveal a unique coordination chemistry mechanism involving space-filling interstitial compartments for stabilizing multi-shell silver clusters.
• This work opens new avenues for designing and synthesizing advanced silver-based nanomaterials with tailored properties.