C-C Coupling of Aryl Chlorides and Reduction of Nitroarenes to Amines Employing Recyclable Heterogeneous Green Catalysts

Two new isostructural inorganic coordination polymers, [M(C14H8O6)(C10H8N2)2H(2)O)] . (C3H7NO), (M=Co, Ni) were prepared employing 2, 5-bis(prop-2-yn-1-yloxy)terephthalic acid (2,5 BPTA) and 4,4 ' bipyridine as ligands. The connectivity between the metal-centers and the ligands give rise to a two-dimensional layer structure. The Ni-containing one has higher stability compared to the Co-containing one. The Co-containing compound, 1, was heated in Ar-atmosphere to prepare Co-nanoparticles, supported over graphitic carbon. The Co@C-T compounds were found to be active for the Bechamp reaction of reduction of nitroarenes to aminoarenes under solvent-free condition with good yields and recyclability. The Ni-containing compound, 2 was loaded with Pd-nanoparticles by known procedures. The Pd@2 samples were found to be a good catalyst for the Suzuki-Miyaura C-C coupling of chloroarenes in ethanol at 75 degrees C in good yield. The present work demonstrates a clean approach for the preparation of new heterogeneous catalysts for the reduction of nitroarenes and especially towards activating chloro-arenes under recyclable reaction conditions. These catalysts and the reactions are green as the Bechamp reaction employing the Co@C-T catalysts was carried out under solvent-free conditions and the Pd@2 catalysis employing environmentally benign ethanol.