Surface-Plasmon-Enhanced Transmetalation between Copper and Palladium Nanoparticle Catalyst

Area of Science:

• Catalysis
• Organic Synthesis
• Photochemistry

Background:

• Traditional cross-coupling reactions often require harsh conditions or specific additives.
• Controlling reaction pathways for selective synthesis remains a key challenge in organic chemistry.

Purpose of the Study:

• To develop a novel, base-free, and additive-free method for Sonogashira and Glaser coupling reactions.
• To demonstrate wavelength-tunable control over reaction pathways using visible light and heterogeneous catalysts.

Main Methods:

• Utilized a mixed heterogeneous catalyst of copper (Cu) and palladium (Pd) nanoparticles.
• Employed visible light irradiation with varying wavelengths (400-940 nm) to drive reactions in an oxygen atmosphere.
• Investigated surface-plasmon-mediated intermediate transfer for transmetalation.

Main Results:

• Achieved efficient C-C bond formation via Sonogashira cross-coupling and Glaser homo-coupling under visible light.
• Demonstrated wavelength-dependent control: shorter wavelengths favored Glaser coupling, while longer wavelengths favored Sonogashira coupling.
• Identified wavelength-dependent regulation of alkyne and iodobenzene intermediate ratios influencing transmetalation.

Conclusions:

• A novel surface-plasmon-mediated transmetalation mechanism enables wavelength-tunable control of cross-coupling and homo-coupling reactions.
• Visible light-driven catalysis with Cu/Pd nanoparticles offers an efficient and selective method for organic synthesis.
• This approach provides a new strategy for optimizing product selectivity in important synthetic transformations.