Catalysis plays a dynamic role in achieving chemical conversions in an economically and commercially viable manner and is the foundational pillar of green chemistry as it offers a clear opportunity to provide realistic solutions to many environmental issues. In the present era, when pollution is a major problem, the focus is also on placing precincts to the use of conventional, corrosive and non-recoverable homogeneous catalysts and identifying robust, easy to handle, and recoverable heterogeneous catalysts. In recent years, magnetic nanoparticles have attracted much attention because of their unique magnetic properties and widespread application in different fields such as mineral separation, magnetic storage devices, catalysis, magnetic refrigeration system, heat transfer application in drug delivery system, magnetic resonance imaging (MRI), cancer therapy, and magnetic cell separation [1–3]. The application of magnetite in the field of waste water treatment is becoming an interesting area of research [4]. Here we prepared a nanocatalyst by immobilization of the Cu(II)-L-Histidine complex on magnetic Fe3O4 nanoparticles. Copper (II) bound to L-histidine is in equilibrium with human serum albumin and may undergo common exchange which modulates the bioavailability of copper to the cell. Cu(II)/L-His@Fe3O4 as a novel, efficient and green nanocatalyst was applied successfully in the synthesis of heterocyclic compounds. The resulted catalyst was used in the synthesis of polyhydroquinolines as biologically interesting compounds, polyhydroquinolines exhibit a wide range of biological activities, such as antitumor, antibiotic, antipyretic, analgesic, antihypertonic and vasodilating behavior [5]. The protocol proves to be efficient and versatile benign in terms of very easy work-up and reused seven times without significant loss of catalytic activity.
