Green synthesis of benzimidazole derivatives under ultrasound irradiation using Cu-Schiff base complexes embedded over MCM-41 as efficient and reusable catalysts
M. Bharathi, Sekar Indira, Govindasamy Vinoth, T. Mahalakshmi, E. Induja, K. Shanmuga Bharathi
Abstract
We have synthesized two recoverable catalysts by covalently attaching complexes such as Cu-complex-phen and Cu-complex-bipy on MCM-41 through a greener synthetic route. FT-IR, EDX, SEM and TEM microscopy, XRD analysis, N2 adsorption and desorption, ICP-OES and TGA were used to characterize the heterogeneous catalysts. The catalytic functioning of Cu-complex-phen-MCM-41 (C1) and Cu-complex-bipy-MCM-41 (C2) were shown yield up to 95% for the synthesis of benzimidazole derivatives in ethanol/methanol solvent under ultrasonic irradiation within 90 min. The catalyst was easily recovered and reused up to three times without significant loss of its activity.