Chiral Ag₂₃ nanocluster with open shell electronic structure and helical face-centered cubic framework

Area of Science:

• Inorganic Chemistry
• Materials Science
• Nanotechnology

Background:

• Silver nanoclusters are of interest due to their unique optical and electronic properties.
• Understanding the precise atomic arrangement and electronic structure is crucial for their application.
• Previous studies have explored various capping ligands and core structures of silver nanoclusters.

Purpose of the Study:

• To synthesize and characterize a novel silver nanocluster with a specific composition and structure.
• To elucidate the crystal structure, ligand binding modes, and electronic properties of the synthesized nanocluster.
• To investigate the relationship between the nanocluster's structure and its optical properties.

Main Methods:

• Synthesis of silver nanoclusters using phosphine and phenylethanethiolate ligands.
• X-ray crystallography for detailed structural analysis.
• Electron paramagnetic resonance (EPR) spectroscopy to determine electronic structure.
• X-ray photoelectron spectroscopy (XPS) to confirm electrical neutrality.
• Time-dependent density functional theory (TD-DFT) calculations for optical property correlation.

Main Results:

• Successful synthesis of a silver nanocluster (Ag23) capped with 8 phosphine and 18 phenylethanethiolate ligands.
• Determination of a helical face-centered cubic core structure with C2 symmetry.
• Identification of novel tri- and tetra-podal thiolate ligand binding modes.
• Confirmation of electrical neutrality and an open-shell electronic structure (5 unpaired electrons).
• Correlation of structural features with observed optical absorption and emission spectra via TD-DFT.

Conclusions:

• The study reports a novel Ag23 nanocluster with unprecedented structural and electronic characteristics.
• The tetra-coordination mode of thiolate ligands represents a new binding motif in silver nanoclusters.
• The open-shell electronic structure is a key feature influencing the nanocluster's properties.
• This work provides fundamental insights into the structure-property relationships of silver nanoclusters, paving the way for future applications.