The Syntheses, Structures And Magnetic Properties Of Transition Metal Complexes With O-Vanillin Schiff Base

The design and synthesis of transition metal ions coordination polymers are attracted considerable interest not only because of their fascinating self-assembled structures but also for their ability to function as progenitors of novel magnetic molecular materials. In this thesis, we have carried out the research on the structures and magnetic properties of transition metal complexes with o-vanillin schiff base. We have synthesized seven multinuclear complexes and four mononuclear complexes.1. Five multinuclear(1-5) and four mononuclear(6-9) compounds have been synthesized with o-vanillin benzoyl hydrazine schiff base ligands(H2L1): [Mn4(μ3-O)2(C15H12N2O3)2(OAc)4]·2CH3CN(1), [Mn2(C15H13N2O3)2(CH3OH)2(py)2](ClO4)2·2py(2), [Mn2(C,5H,3N2O3)3]·ClO4·CH3OH(3), [Cu2(C15H13N2O3)2(C3H4N2)2]·2ClO4(4), [Cu4(C15H12N2O3)4]·3CH3CN(5),Fe(C15H13N2O3)2]Cl·H2O(6), [Co(C15H12N2O3)(C5H5N)3] ClO4(7), [Ni(C15H13N2O3)2]ClO4·1.5H2O(8) and [Cu(C15H13N2O3)(C3H4N2)]ClO4(9).2. Defective cubane-like tetranuclear nickel with o-vanillin glycine derivative ligand(H2L2) have been obtained. ([Ni4(C10H11NO4)2(C12H8N2)2(CH3O)2(H2O)2](ClO4)2 (10))3. A cubane-like tetranuclear nickel with o-vanillin group ligand have been obtained. ([Ni(μ3-OCH3)(C8H8O3)(H3OH)]4(11))These ligands display a variety of bonding geometries, such as chelating, monodentate/ bidentate bridging, and chelating bridging. In addition, the temperature dependence of the direct current magnetic susceptibility of complexes (1,2,5,6,11) was measured, which revealed that the different complexes exhibit anti-ferromagnetic interactions.