Mechanochemical solid state synthesis of copper(I)/NHC complexes with K₃PO₄

Area of Science:

• Organometallic Chemistry
• Green Chemistry
• Catalysis

Background:

• Traditional synthesis of copper(I)/N-heterocyclic carbene (NHC) complexes often involves silver(I) precursors, leading to significant waste and high solvent usage.
• Developing sustainable and efficient synthetic protocols for NHC-metal complexes is crucial for advancing catalytic applications.

Purpose of the Study:

• To develop a mechanochemical protocol for synthesizing copper(I)/NHC complexes using an inexpensive base.
• To demonstrate the versatility of this method for both simple and complex NHC ligands.
• To highlight the environmental benefits compared to conventional methods.

Main Methods:

• Mechanochemical synthesis utilizing a ball mill.
• Employing potassium phosphate (K3PO4) as a readily available and inexpensive base.
• Characterization of the synthesized copper(I)/NHC complexes.

Main Results:

• Successful synthesis of various copper(I)/NHC complexes, including those with guanidine moieties, via mechanochemistry.
• The developed protocol avoids the use of silver(I) complexes, reducing waste and solvent consumption.
• The synthesized copper(I)/NHC complexes function as effective bifunctional catalysts in reduction/hydrogenation reactions using dihydrogen.

Conclusions:

• Mechanochemical synthesis offers a sustainable and efficient route to copper(I)/NHC complexes.
• This method presents a greener alternative to traditional synthesis, minimizing environmental impact.
• The resulting catalysts are highly active in important catalytic transformations.