LAUSR

Abstract A novel magnetic heterogeneous nanocatalyst CoFe2O4@SiO2@NH-NH2-PCuW was synthesized and characterized. This powerful catalyst possesses Bronsted and Lewis acid properties. The presence of Cu enhances the acidity of this catalyst because of the increase in the electron deficiency of polyoxometalate. It was successfully applied for the easy and efficient one-pot synthesis of 1,4-benzodiazepine derivatives directly from dimedone, o-phenylenediamine, and an aromatic aldehyde under a solvent-free condition at 80 °C. High yields in short reaction times, easy work-up, and environmental friendliness are some of the advantages of this protocol. Also, this nanocatalyst could conveniently be recovered by a magnetic field and reused several times without a significant loss of catalytic efficiency. The synthesized nanocatalyst CoFe2O4@SiO2@NH-NH2-PCuW also proved to be an excellent adsorbent for dye removal. These properties are related to the high surface area because of the nanostructure and high acidity due to the presence of Cu in polyoxometalate. Moreover, magnetic properties help better recovering of this adsorbent for dye removed from wastewater.