Relaxation Regulation Of Oxygen Bridged Dinuclear Ruthenium Molecular Magnets

Eighteen binuclear earth complexes were designed and synthesized by reacting oxygen-containing or nitrogen-containing and ?-diketonate ligands with rare earth ions.They have been characterized by X-ray single crystal analysis,Fourier transform infrared,elemental analyses and PXRD etc.Through tuning the structure of ligands to modulate the coordination environments and molecule symmetry of spin center,and consequently control the ligand field.Meanwhile,the intramolecular magnetic exchange interaction is introduced to suppress the quantum tunneling of magnetization(QTM)and further to enhance the anisotropy energy barrier of these complexes.Their magneto-structural correlations were investigated combining the structural and magnetic analysis with the ab inito calculation.The contents are as follows:1.Ten lanthanide binuclear complexes with formula[Dy2(DMOP)2(NTFA)4](1),[Dy2(DMOP)2(NTFA)4(CH30H)2·2H2O](1a),[Dy2(DMOP)2(BTFA)4](2),[Dy2(DMOP)2(TTA)4](3),[Y2(DMOP)2(TTA)4](3Y),[Tb2(DMOP)2(NTFA)4](4),[Tb2(DMOP)2(NTFA)4(CH3OH)2·2H2O](4a),[Er2(DMOP)2(NTFA)4](5),[Gd2(DMOP)2(NTFA)4(CH3OH)2·2H2O](6),[Gd2(DMOP)2(TTA)4](7)(DMOP =2,6-Dimethoxyphen,NTFA= 2-Naphtoyltrifluoroacetone,BTFA =Benzoyltrifluoroacetone,TTA = Thenoyltrifluoroacetone)were designed and synthesized.The Dy(?)-based derivatives show significant single-molecule magnet behavior under zero dc field.In addition,the change from antiferromagnetic to ferromagnetic coupling deriving from the intramolecular Dy-Dy interaction was found in 1 and la.Magnetic diluted experiments and ab initio calculations were implemented to explore the mechanism of magnetic relaxation.2.A series of complexes were designed and synthesized by L(L =2,6-dimethoxybenzoic acid),namely,Dy2(DBM)4L2(CH3CH2OH)2·2CH2Cl2(8),Dy2(DBM)4L2(CH3OH)2·2CH2Cl2(9)and Dy2(BAC)4L2(CH3CH2OH)2(10)(DBM =dibenzoylmethane,BAC = Benzoylacetone).The magnetic measurements also show that all complexes exhibit slow magnetic relaxation under applied dc fields.3.Double ?-diketonate SIMs are bridged by bipyrimidine(BPYM)or 3,6-Di(2-pyridyl)-1,2,4,5-tetrazine(DPTZ)ligand to form five dinuclear Dy2 SMMs(11-15)and their SMMs behaviors are studied.