Synthesis, Characterization and Catalytic Activity of Nanometric Complexes
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SYNTHESIS, CHARACTERIZATION AND CATALYTIC ACTIVITY OF NANOMETRIC COMPLEXES Kripa Mody 1 , Bhavna Trivedi 1 and Arun Pratap 2 1 Department of Chemistry, Faculty of Science, M.S. University of Baroda Vadodara-390 002 (INDIA). 2 Department of Applied Physics, Faculty of Technology & Engineering ,M.S.University of Baroda, Vadodara-390 001 (INDIA). ABSTRACT The preparation and characterization of nanostructured materials and catalysts is the focus of intense study in recent years. The micro emulsion technique is one of the chemical methods known for isolation of nano-sized materials and some simple compounds such as AgCl and LiF have been prepared using this technique. However, very few attempts have been made to isolate nano-sized coordination compounds, which are known to be good catalysts. In the present paper, nano-sized complexes of Cu(II) and Ni(II) with Leucine were prepared by the reaction of metal chloride and the ligand solution in water in oil micro-emulsion medium. N-Heptane was used as oil and sodium salt of dioctyl sulfo succinate (AOT) was used as surfactant to stabilize the emulsion. The complexes were characterized by elemental analysis and spectral studies. The crystallite sizes were determined by XRD studies using single line approximation through Scherrer equation. The X- ray diffraction studies revealed that the crystallite size of the complexes prepared by micro-emulsion technique was smaller than that of the material prepared by conventional method. The difference in particle size was also observed in differential scanning calorimetric (DSC) studies, where in, the reaction peaks were observed at lower temperatures for the complexes prepared by the micro-emulsion technique. The increased surface to volume ratio is expected to give better catalytic behavior. INTRODUCTION It is known that the physical, chemical, mechanical and other properties of materials resulting from nanocrystals are far different from those of the original parent materials. Because of their unusual properties, nanomaterials and nanocomposites have created an intense interest in recent years1. Roughly, two kinds of nanostructure induced effects can be distinguished : first the size effect, in particular the quantum size effect, where the normal bulk electronic structure is replaced by a series of discrete electronic levels and second the surface or the interface induced effect, which is important because of the enormously large specific surface area. While the size effect is mainly considered to describe physical properties, the surface or the interface induced effect plays an important role for chemical processing, in particular, in heterogeneous catalysis. A number of chemical and physical preparative methods to produce materials with nanometer structure have been reported2. For the preparation of inorganic compounds, wet chemical route reverse miscelle technique is found to be more convenient; for example for the preparation of Bi-Pb-Sr-Ca-Cu oxide superconductor, it’s precursor, nanosized oxalates of Ba 2+ ,Pb2+, Sr 2+ ,Ca 2+,
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