Investigation Of The Synthesis,Structures And Magnetic Properties For Molecule-based Magnetic Materials Based On 2-hydroxymethyl Pyridine Ligand

Molecule-based magnetic materials possess adjustable structure,small magnetic loss,good solubility and light texture,which have great application prospect in high density information storage,molecular switch and so on.A variety of molecule-based magnetic materials with various magnetic properties have been synthesized,such as antiferromagnetic,ferrimagnetic,ferromagnetic,spin flop,spin glass,spin canting,spin crossover,etc.However,it remains a challenging task to synthesize crystals with desired structures and adjust the magnetic properties,then obtain molecule-based magnetic materials with target magnetism.In this dissertation,we report eight compounds synthesized by using 2-hydroxymethyl pyridine（Hhmp）and formate as ligands and research the relationship of structure-magnetic:1.Two new enneanuclear cobalt（Ⅱ）cluster based complexes [Co9（hmp）6（CHOO）6（CO3）2（H2O）6]（ClO4）2·11H2O（1）and [Co9（hmp）6（CHOO）7（CO3）2（H2O）5] ClO4·CH3CN·12H2O（2）bridged by Hhmp,μ2-formate and μ6-CO3 derived from atmospheric CO₂ are successfully synthesized.By replacing one neutral water ligand with one formate anion,the {Co9}2+ cluster in 1 was changed into {Co9}+ in 2,leading to the different cluster alignment in 1 and 2.The tuning of charges on the clusters results in the changing of the intermolecular interactions.As a result,compound 1 shows antiferromagnetic behavior and compound 2 exhibits spin-glass magnetic exchange.2.Three new cubane-containing compounds based on Hhmp ligand,namely,[Cu4（hmp）4（CHOO）2（H2O）2]（ClO4）2·2H2O（3）,[Cu8（hmp）8（CHOO）4（CH3CN）2（H2O）4]（Cl O4）4·2CH3CN（4）,{[Cu2（hmp）2（CHOO）（H2O）]ClO4·H2O}n（5）,have been synthesized by solvent induction.Changing the solvent ratio,the isolated copper cubane of 3 is successfully changed into octa-nuclear copper cluster 4 with double [Cu4O4] cubanes,which is further extended into polycubane chain 5 via bridging ligand of formate.Monocubane 3 and dicubane 4 both exhibit antiferromagnetic behavior and compound 5 with polycubane shows ferromagnetic interaction.3.Three new cubane compounds based on Hhmp ligand have been successfully synthesized by changing centre metal and solvent ratio,namely,[Ni4（hmp）4（CHOO）2（H2O）4]（ClO4）2（6）,[Ni4（hmp）4（CHOO）4（H2O）2]·5.5H2O（7）,[Co4（hmp）6（H2O）2（CH3CN）2]（ClO4）4·4CH3CN（8）.Tetra-nuclear nickel compounds 6 and 7 possess similar structure with different metal coordination environment,both existing antiferromagnetic interaction.The tetra-nuclear defect double-cubane 8 shows long-range ordering.