Gold(I) Catalysis in Alkyne-Alkene Reactions: A Systematic Exploration through Molecular Electrostatic Potential...

Area of Science:

• Organometallic Chemistry
• Catalysis
• Computational Chemistry

Background:

• Gold(I) complexes are effective catalysts for selective organic transformations.
• Ligand choice significantly influences gold-catalyzed reaction rates and selectivity.
• Understanding ligand effects is crucial for designing efficient catalytic systems.

Purpose of the Study:

• To investigate the impact of phosphine ligands (PR3) on gold(I)-catalyzed alkyne-alkene cyclobutene formation using DFT.
• To analyze key steps in the catalytic cycle, including complexation, binding, C-C coupling, and product dissociation.
• To establish Molecular Electrostatic Potential (MESP) as a tool for understanding ligand influence.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Analysis of key catalytic steps: complexation, substrate binding, transition states, and dissociation.
• Molecular Electrostatic Potential (MESP) analysis to probe electronic effects.

Main Results:

• A strong correlation was found between MESP changes at the gold nucleus and complexation energy.
• MESP changes at alkyne carbons correlated with the C-C coupling activation barrier.
• Electron-donating phosphine ligands and electron-withdrawing alkyne substituents enhance catalyst turnover and regeneration.
• Bulky ligands (XPhos, JohnPhos, CyJohnPhos) improve catalysis through steric and electronic effects.

Conclusions:

• MESP is a valuable tool for understanding ligand effects in gold catalysis.
• Optimized ligand and substrate electronic properties enhance catalytic efficiency.
• Steric and electronic factors of bulky ligands contribute to improved gold(I) catalysis.
• This study provides fundamental insights for designing next-generation gold catalysts.