Gold(III) stabilized over ionic liquids grafted on MCM-41 for highly efficient three-component coupling reactions

Area of Science:

• Materials Science
• Catalysis
• Organic Synthesis

Background:

• Ionic liquids (ILs) offer unique properties for catalysis.
• Mesoporous silica, MCM-41, is a versatile support material.
• C-H bond activation is crucial for efficient organic synthesis.

Purpose of the Study:

• To synthesize alkoxysilyl-modified ionic liquids and graft them onto MCM-41.
• To utilize these functionalized materials as supports for gold catalysts in A(3) coupling reactions.
• To investigate the catalytic performance and stability of the developed gold-MCM-41 system.

Main Methods:

• Synthesis of alkoxysilyl-modified ionic liquids.
• Grafting of ionic liquids onto MCM-41 via silanol groups, confirmed by (29)Si NMR.
• Dispersion of AuCl3 on the functionalized MCM-41 for catalytic A(3) coupling.

Main Results:

• Successful covalent grafting of ionic liquids onto MCM-41 was confirmed.
• The synthesized IL-functionalized Au-MCM-41 exhibited higher catalytic activity than homogeneous Au(III) and supported Au(III)-MCM-41 catalysts.
• Stabilization of Au(III) species by the ionic liquid was observed, but gold leaching led to decreased activity over successive cycles.

Conclusions:

• Alkoxysilyl-modified ionic liquids grafted onto MCM-41 provide an effective platform for gold catalysis.
• The IL-functionalized support enhances catalytic activity in A(3) coupling reactions.
• Strategies to mitigate gold leaching are necessary for sustained catalytic performance.