Development of Noval, Recyclable, and Tunable Aryl Imidazolium Salts with a Dual Brønsted–Lewis Acid Character as Catalysts for the Copper(I)-Catalyzed Azide–Alkyne Cycloaddition Reaction (CuAAC)

Abstract

The development of novel aryl imidazolium salts (ISs) with dual Brønsted–Lewis acid character represents a significant advancement in the field of green chemistry and catalysis. These imidazolium salts serve as efficient catalysts for the copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction, a cornerstone of click chemistry. The unique design of the aryl imidazolium framework, incorporating both Brønsted and Lewis acid sites, enhances the catalytic efficiency and selectivity of the CuAAC reaction. Furthermore, the use of these imidazolium salts as catalysts eliminates the need for additional phase-transfer catalysts or cosolvents, simplifying the reaction setup and reducing environmental impact. This study demonstrates the synthesis, characterization, and application of these novel imidazolium salts, highlighting their potential as sustainable and efficient media for CuAAC reactions. The developed catalyst is stable in water and air, and the highest catalytic activity could still be maintained after 4 cycles. The results indicate that the novel, recyclable, and tunable aryl imidazolium salts with dual Brønsted–Lewis acid properties offer a promising platform for the development of greener and more efficient catalytic processes in organic synthesis.