Carborane-Cluster-Wrapped Copper Cluster with Cyclodextrin-like Cavities for Chiral Recognition

Area of Science:

• Supramolecular Chemistry
• Nanomaterials Science
• Chiroptical Spectroscopy

Background:

• Chiral atomically precise metal clusters exhibit promising chiroptical properties for chirality recognition.
• Limited exploration of host-guest chemistry involving metal clusters has hindered advancements in this field.
• Developing novel chiral hosts for selective molecular recognition remains a significant challenge.

Purpose of the Study:

• To synthesize and characterize a novel chiral metal cluster with host-guest capabilities.
• To investigate the cluster's ability to recognize and quantify amino acids using chiroptical signals.
• To explore the functional synergy between carborane and metal clusters for chirality sensing.

Main Methods:

• Synthesis of the chiral Cu₁₆(C₂B₁₀H₁₀S₂)₈ (Cu₁₆@CB₈) cluster using an achiral carboranylthiolate ligand.
• Chiroptical analysis (circular dichroism and circularly polarized luminescence) for amino acid recognition.
• Density functional tight-binding molecular dynamics simulations and noncovalent interaction analysis.

Main Results:

• The synthesized Cu₁₆@CB₈ cluster possesses chiral cavities capable of specific amino acid recognition.
• Responsive chiroptical signals from Cu₁₆ moieties enabled quantitative analysis and deracemization of amino acids.
• Demonstrated generality for dipeptides, tripeptides, and polypeptides containing specific amino acid residues (Cys, Arg, His).

Conclusions:

• The Cu₁₆@CB₈ cluster showcases the first demonstrated functional synergy of dual carborane and metal clusters.
• This system enables rapid quantification of enantiomeric excess (ee) values for amino acids.
• Opens new avenues for designing advanced chirality sensors based on chiral metal clusters and host-guest chemistry.