Silica-based pyrrolidinium ionic liquid immobilised on copper-citric acid metal-organic framework, ([PyrrSi][Cl]@Cu-Cit-MOF): Heterogeneous catalysis to the multicomponent reaction for the synthesis of imidazoles
Nazia Zameer, Atif Mustafa, Nida Khan, Zeba N. Siddiqui
Abstract
A novel, silica-based pyrrolidinium ionic liquid immobilised on copper-citric acid metal-organic framework ([PyrrSi][Cl]@Cu-Cit-MOF), has been synthesised through an easy-to-handle procedure and is characterised by several techniques such as Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), powder X-ray diffraction (PXRD), thermal gravimetric (TG), and Brunauer-Emmett-Teller (BET) analyses. The present protocol is scalable and compatible with a wide range of aldehydes, producing imidazole derivatives in excellent yields (82-96 %) in very short reaction times (10–18 min). Moreover, the catalyst could be recovered and recycled simply by filtration and is reusable for up to six consecutive runs without any significant changes in its catalytic activity.