Catalytic reduction of aromatic nitro compounds by copper-schiff base complex immobilized covalently on magnetic nanoparticles as a new, efficient and recyclable catalyst

Compounds containing a nitro group are valuable substrates in organic synthesis. In particular, nitroarenes are one of the most readily available starting materials in organic synthesis since they can be produced from a range of aromatic starting materials [1]. One of the major pathways for the transformation of nitroarenes is their hydrogenation into anilines. Moreover nitro compounds are highly toxic and do not undergo biodegradation easily. Thus the elimination of nitro groups can be achieved by the reduction of amines with low toxicity and easily biodegradable [2]. A number of techniques for the reduction of nitroarenes have been developed. Although the reported methods are acknowledging, most of them suffer from one or more of the following drawbacks: high temperature, low yields of the products, prolonged reaction times, tedious work-up procedures, use of expensive or non-recyclable catalysts, hazardous solvents and generating large amounts of waste [3]. In this work, magnetically recyclable Cu-iminopy-MNPs has been synthesized and characterized by different methods. The catalytic activity of this newly synthesized catalyst for the reduction of nitro compounds in water has been studied (Scheme 1). The results showed high catalytic activity of this catalytic system for the hydrogenation reaction of various nitroarenes using NaBH4 as hydrogen donor. Good to high yields (60-98%) of the products, using water as green reaction media and ease of separation and reusability of the catalyst are the advantage of this method.