Copper Single-Atom Catalyst for Efficient C─S Coupling in Thioether Synthesis

Area of Science:

• Heterogeneous catalysis
• Materials science
• Organic synthesis

Background:

• Carbon-sulfur (C─S) bond formation is crucial for synthesizing thioethers used in pharmaceuticals, agrochemicals, and materials.
• Current industrial methods for C─S coupling often employ expensive homogeneous catalysts with poor recyclability and susceptibility to sulfur poisoning.
• Developing efficient, selective, and robust catalysts for C─S cross-coupling remains a significant challenge in synthetic chemistry.

Purpose of the Study:

• To develop an efficient, selective, and recyclable catalyst for carbon-sulfur (C─S) cross-coupling reactions.
• To investigate the use of a copper single-atom catalyst supported on mesoporous graphitic carbon nitride for C─S bond formation.
• To provide mechanistic insights into the catalytic process and demonstrate its applicability on a gram scale under mild conditions.

Main Methods:

• Synthesis and characterization of a copper single-atom catalyst atomically dispersed on mesoporous graphitic carbon nitride.
• Testing the catalyst's performance in carbon-sulfur (C─S) cross-coupling reactions under mild conditions.
• Utilizing advanced characterization techniques (electron microscopy, X-ray absorption spectroscopy, EELS) and computational simulations (DFT) for mechanistic studies.

Main Results:

• The copper single-atom catalyst demonstrated high efficiency and selectivity in C─S cross-coupling reactions.
• The catalyst exhibited excellent resistance to thiol poisoning and maintained high performance over multiple catalytic cycles, confirming its recyclability.
• Mechanistic investigations supported a concerted oxidative addition pathway, ruling out radical intermediates, and confirmed the atomic dispersion and stability of Cu sites.

Conclusions:

• Atomically dispersed copper on mesoporous graphitic carbon nitride serves as a highly effective heterogeneous catalyst for C─S cross-coupling.
• This single-atom catalyst approach overcomes limitations of traditional methods, offering enhanced stability, recyclability, and resistance to sulfur poisoning.
• The findings pave the way for greener, more scalable synthetic processes for fine chemicals and pharmaceuticals utilizing C─S bond formation.