Design, Synthesis And Magnetic Properties Of Flexible Phenolic-amine Complexes

This thesis concentrated on the synthesis, structures and magnetism ofzero-dimensional and1-D molecule-based magnetic magnets based on a rangeof flexible phenolic amine ligands, especially multinuclear transition metalcomplexes and hetrometallic multinuclear transition-rareearth metal complexes.The main results of the paper are as follows:1. A series of hexanuclear hetrometallic MnIII2MIII4(M=Y(1), Gd(2), Tb(3),Dy(4)) compounds, a series of octanuclear hetrometallic MnIII4MIII4(M=Y(5),Gd(6), Tb(7), Dy(8)) compounds and a octanuclear hetrometallic FeIII4TbIII4(9)compound have been synthesized through self-assembly method. In hexanuclearMnIII2MIII4series, the rare-earth metal ions form a planar tetranuclear structureand the coordination sphere of MnIIIis a five-coordinate trigonal bipyramidal. Inoctanuclear MnIII4MIII4series, rare-earth metal ions form a deformationhexahedral structure with fourμ4-O2-. Compound3and4performance fieldinduced SMM behavior.2. Three cases of hetrometallic dinuclear NiIILnIII(Ln=Gd(10), Tb(11),Dy(12)) compounds, one case of ZnIIDyIII(13) compound and three cases ofCoIIMIII(M=Y(14), Dy(15), Gd(16)) compounds have been synthesized with ahexa-dentate flexible ligand. DBM was used as a co-ligand. In these compounds,transition metals and rare earth metal ions are bridged by two phenoxo bridginggroups. Magnetic measurements show that compoud11and compound12performance SMM behavior. Compound13, Compound14, respectivelyperformance DyIIIand CoIISIM behavior. Compound15is the first case ofsingle molecule magnet constructed from exchange-coupled Single ion magnets.By replacing DyIIIfor the magnetic isotropic GdIIIionic compound16has beensynthesized, which does not exhibit any SMM behavior. This series of fixeddinuclear structure can be used as a template of the study of interactions ofdifferent types of magnetic metal ions’s affecting to the nature of the system’sSMM behavior.3. Four straight mixed-valence trinuclear MnIII2MnII(17-20) compounds, one trinuclear CuII3(21) compound, one pentanuclear CuII3CuI2(22) compound,two plane triangle MnIII3(23-24) compounds and one1-D MnIII3MnIINaIcompound have been constructed with a series flexible phenolic amine ligands.Magneto-structural correlation studies of compouds17-20show that a largerMnII-Oalkoxide-MnIIIbridging bond angleleads to a stronger ferromagneticcoupling in such type of multinuclear manganese complexes. Magneto-structuralcorrelation studies of compouds21and22show that a larger CuII-Ophenolate-CuIIbridging bond angleleads to a stronger antiferromagnetic coupling in such typeof multinuclear copper complexes.