Mononuclear Manganese(IV) Complexes Derived from Polyfunctional Fumaryldihydrazone

Abstract

A series of mononuclear manganese(IV) complexes of disalicylaldehyde fumaroyldihydrazone (slfhH4) were synthesized by reacting manganese acetate tetrahydrate with dihydrazone in absence and presence of various pyridine bases in methanol medium. Pyridine (py) and its derivatives like 2-picoline (2-pic), 3-picoline (3-pic), 4-picoline (4-pic), 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) were added to the reaction mixture of metal salt and dihydrazone to explore the binding possibilities of these molecules to manganese center. The elemental analysis, mass spectral and thermal studies were used to derive their composition. Study of magnetic moment, molar conductances, electronic, EPR and infrared spectroscopy have led to interpretation of their tentative structures. Magnetic moment and EPR studies correspond to their Mn(IV) oxidation state. The dihydrazone functions as tetradentate ligand chelating the manganese(IV) ion present in octahedral geometry with anti-cis configuration in enol form. Electrochemical and antimicrobial studies were also performed.