Novel chloride-centered Ag₁₈ clusters featuring a cuboctahedral Ag₁₂ skeleton

Area of Science:

• Inorganic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Silver clusters are of interest due to their unique electronic and optical properties.
• Understanding cluster formation mechanisms is crucial for designing novel materials.
• The role of supporting ligands in stabilizing complex metal clusters is an active area of research.

Purpose of the Study:

• To synthesize and characterize novel chloride-centered silver clusters.
• To investigate the influence of different phosphine ligands on cluster structure.
• To elucidate the mechanism of cluster formation, particularly the origin of the central chloride.

Main Methods:

• Synthesis of silver clusters using specific precursors: PhC≡CAg, AgSbF₆, PPh₃ or P(p-Tol)₃, NaBH₄, CH₂Cl₂, and NEt₃.
• Structural characterization of the resulting Ag₁₈ clusters.
• Analysis of reaction pathways, including the Menshutkin reaction between CH₂Cl₂ and NEt₃.

Main Results:

• Two novel Ag₁₈ clusters with identical frameworks but different phosphine ligands were successfully synthesized.
• The inner twelve silver atoms adopt a rare cuboctahedral arrangement, influenced by ligand effects.
• The central chloride ion was identified as originating from the Menshutkin reaction between dichloromethane and triethylamine.

Conclusions:

• Ligand properties significantly impact the structural outcome of silver cluster synthesis.
• The Menshutkin reaction between CH₂Cl₂ and NEt₃ is a key pathway for generating the central chloride in these clusters.
• This study provides valuable insights into silver cluster formation mechanisms and ligand-dependent structural control.