Combining ethylenediamine and ionic liquid functionalities within SBA-15: A promising catalytic pair for tandem Cu-AAC reaction

This paper discloses the assembly and characterization of an advanced heterogeneous catalyst formulated as CuI@SBA-15/PrEn/ImPF(6). It is based on a mesoporous silica SBA-15 skeleton which bears a supported ethylenediamine/CuI complex and covalently anchored imidazolium/PF6 ionic liquid. This catalyst was successfully applied in tandem methods for triazole synthesis starting from different substrate pairs: aryl halides and aryl acetylenes (method A), arylboronic acids and aryl acetylenes (method B). The CuI@SBA-15/PrEn/ImPF(6) catalyst showed high activity (up to 90% yields of triazole products under optimized reaction conditions), high stability and no appreciable leaching of CuI owing to its strong binding via the coordination with PrEn functionality. Therefore, the catalyst can be recycled for several consecutive runs (714 cycles) in this new synthetic method. For both methods A and B, specific types of green approaches were developed and the favorable products were produced in high yields.