| Functional complexes constructed by organic ligands with nitrogen or oxygen multi-coordination sites and 3d transition or lanthanide(4f)metal ions have abundant structures and special optical and magnetic properties,which are developing into research hotspots in the fields of magnetic,fluorescent,and catalytic materials.In this paper,ten novel 3d and 4f metal complexes are designed and synthesized by selecting two organic ligands of 3-(tetrazole-5-yl)-5-(pyridin-2-yl)-1,2,4-triazole(H2TPT)and 2-hydroxy-3-methoxybenzoic acid(H2MBA)with multiple coordination sites to react with 3d and 4f metal salts,and their structures,magnetic and fluorescent properties are studied and analyzed.The contents are as following:1.Four 3d metal complexes[Co?2(TPT)2(H2O)2](1),[Mn?2(TPT)2(H2O)2](2),[Mn?(TPT)(H2O)2]n(3)and[Cu?(TPT)]n(4)based on H2TPT ligand were synthesized under hydrothermal/solvothermal conditions.X-ray single crystal diffraction results show that complexes 1 and 2 are isostructural dinuclear structures,complex 3 is a one-dimensional zigzag chain structure,complex 4 is a three-dimensional framework structure.The direct current susceptibility tests revealed complexes 1-4 exhibit antiferromagnetic exchange interactions,while 1 and 4 show strong magnetic exchange interactions.The alternating current susceptibility test was performed on complex 1,but no slow magnetic relaxation behavior was observed.In addition,the electrocatalytic effect of complexes 1-4 on water decomposition were tested under neutral conditions,and complex 1 shows better catalytic activity.2.Four Dy(?)complexes[Dy(HMBA)(MBA)(DMF)(H2O)]·3H2O(5,DMF=N,N-dimethylformamide),[NH4][Dy(HMBA)4](6),[Dy3(MBA)3(HMBA)(OH)2(H2O)3]·10H2O(7)and[Dy6(MBA)6(OH)4(H2O)8](OH)2·33H2O(8)based on H2MBA ligand were designed and synthesized by controlling the ratio of raw materials.Structural analyses found that 5 is a dinuclear structure,6 is a one-dimensional beltlike structure,7 is a one-dimensional zigzag chain constructed by triangular Dy(?)3 units,and 8 is a two-dimensional network structure.Fluorescence measurements show that H2MBA ligand can effectively sensitize the characteristic luminescence of Dy(?)ion in complexes 5-8.Complexes 6,7 and 8 can balance the blue light emitted by the H2MB A ligand and the main yellow light emitted by the Dy(?)ion under the excitation of ultraviolet light,and emit white light that are suitable for illumination.Magnetic susceptibility tests show that 5 and 6 exhibit single-molecule magnet behaviors under 0 and 1200 Oe direct current field,respectively.The corresponding energy barriers are 90(2)and 31(5)cm-1 for 5 and 6,respectively.7 and 8 exhibit single-molecule toroic magnet behavior under zero direct current field,and the corresponding energy barriers are 5.2(9)and 31(2)cm-1,respectively.7 and 8 are the first reported one-and two-dimensional homonuclear single-molecule toroic magnets.Furthermore,magnetic relaxation processes of 5-8 were studied by theoretical ab initio calculations.3.Two Yb(?)complexes[Yb(HMBA)(MBA)(DMF)(H2O)]-3H2O(9)and[NH4][Yb(HMBA)4](10)were obtained by the reaction of the organic ligand of H2MB A with Yb(?)ion salt.Structural analyses show that 9 is a dinuclear structure and 10 is a one-dimensional beltlike structure.Fluorescence measurements show that 9 and 10 emit H2MBA ligand-sensitized Yb(?)characteristic near-infrared fluorescence.Magnetic susceptibility measurements show that 9 and 10 show slow magnetic relaxation behaviors under 600 and 2500 Oe direct current field,respectively.The energy barriers are 18(3)and 20(1)cm-1 for 9 and 10,respectively.In addition,the magnetic relaxation processes were revealed through theoretical ab initio calculation. |
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