Ru (III) Schiff-base complex anchored on nanosilica as an efficient and retrievable catalyst for hydration of nitriles

Abstract

Transition metal catalyzed hydration of nitriles is an attractive methodology for amide synthesis, and hence recently attracted wide attention. It is one of the significant organic transformations as amides play a vital role in biological, pharmaceutical and industrial applications. In this work, we report the synthesis of a new solid supported Ru (III) Schiff base complex, Ru@imine-nanoSiO2 immobilized on nanosilica obtained from rice husk. The complex was characterized by FTIR, powder X-ray diffraction, BET surface area measurement, UV–vis, SEM–EDX, TEM, ESR, X-ray photoelectron spectroscopy and ICP-AES analysis. Using Ru@imine-nanoSiO2 as the catalyst, the hydration of nitriles in i-PrOH at 40 °C was studied which resulted in good isolated yields (60–99%). The catalyst can be recycled and reused up to 5th cycle without any loss in activity. The products were characterized by FTIR, GC–MS and 1H-NMR spectroscopy and compared with authentic samples.