Atomically precise copper clusters with dual sites for highly chemoselective and efficient hydroboration

Area of Science:

• Organometallic Chemistry
• Catalysis
• Synthetic Organic Chemistry

Background:

• Alkyne hydroboration to vinylboronate esters is crucial but challenging regarding selectivity and catalyst efficiency.
• Developing catalysts with high turnover numbers and chemoselectivity remains a significant hurdle in organic synthesis.

Purpose of the Study:

• To develop novel copper cluster catalysts for enhanced alkyne hydroboration.
• To investigate the catalytic performance, selectivity, and reusability of these new catalysts.
• To elucidate the mechanistic basis for the observed catalytic activity.

Main Methods:

• Synthesis and characterization of dual-catalytic-site copper clusters (Cu4NC and Cu8NC) with N-heterocyclic thione ligands.
• Evaluation of catalyst performance in alkyne hydroboration under mild conditions.
• Mechanistic studies including density functional theory (DFT) calculations.

Main Results:

• The microcrystalline Cu4NC catalyst exhibited a high turnover number (77,786) and excellent chemoselectivity.
• Cu4NC demonstrated high recovery and reusability, along with superior catalytic activity compared to Cu8NC.
• DFT calculations indicated a lower activation energy for hydroboration with the Cu4NC catalyst.

Conclusions:

• Precisely engineered cluster catalysts with dual catalytic sites can significantly enhance catalytic properties.
• Synergistic interactions and dynamic ligand effects in Cu4NC contribute to its high catalytic activity.
• This research provides a pathway for developing advanced cluster catalysts for improved chemical transformations.