Spectral, Crystalline, Thermal, Morphological characterization and Catalytic Performance of Ruthenium(III) Complexes of Natural Biopolymer Based on Schiff base Ligands

Aims: The aim of this study is to achieve catalytic performance for oxidation of alcohols using Ruthenium(III) metal complexes as a catalyst. Background: The chitosan is a potential candidate which enables synthesis of transition metal complexes from its corresponding bidentate ligands. Method: The chemical modification was performed on chitosan molecule with suitable aldehydes. The oxidation of alcohols was performed using ruthenium metal complexes as catalysts with Pyridinium chlorochromate (PCC) as oxidant and dichloro methane as solvent. To a solution of alcohol (2mmol) in dichloromethane (25mmol), Pyridinium chlorochromate (3 mmol) and Ruthenium(III) complexes (0.01mmol) were added. The solution was stirred for 12 h at room temperature. At the required time, the aldehyde / ketone was extracted with n-hexane. Then hexane was analyzed by GC. Results: The ruthenium(III) complexes derived from modified chitosan Schiff bidentate ligands resulted in good catalytic performance for oxidation of alcohols under optimized conditions. Conclusion: The enhanced catalytic activities of ruthenium(III) complexes were due to the presence of electron donating groups in the Schiff base ligand. : Ruthenium(III) complexes [Ru(CS)4hy3mbd)(H2O)2Cl2] and [Ru(CS)2hybd)(H2O)2Cl2] have been synthesized and characterized by FT-IR, X-ray diffraction, Thermo-gravimetric analysis and SEM with EDX. The ruthenium complexes were derived from chitosan biopolymer based Schiff base ligands. The N and O donor atoms of chitosan Schiff base ligands were involved in complexation reaction with Ruthenium metal ion to form stable coordination complex. This synthesized Ruthenium(III) complexes acted as active catalyst for the oxidation of primary and secondary alcohols which has converted to corresponding aldehydes and ketones at suitable reaction conditions. The oxidation of alcohols was performed using ruthenium metal complexes as catalyst with Pyridinium chlorochromate (PCC) as oxidant and dichloro methane as solvent.