The Research Into Photo-luminescent And Magnetic Functional Complexes Constructed By 8-Hydroxyquinoline Derivatives And ?-diketone

The rare earth elements have attracted considerable attention for their special electronic structure.The lanthanide luminescent materials and magnetic materials have been the current research hotspot.So it is of great importance to design and synthesize functional lanthanide complexes.Ligand design is a key factor in constructing lanthanide complexes.?-diketone ligands have been widely chosen by researchers due to their two oxygen atoms which are easy to coordinate with the lanthanide metal.In addition,8-hydroxyquinoline unit or its derivatives are promising building blocks in synthesizing functional materials.However,much attention has been paid to the investigation of luminescent properties of 8-hydroxyquinoline-based complexes.Recently,the preparation of 8-hydroxyquinoline-based lanthanide SMMs gained some impetus but the reported lanthanide SMMs based on 8-hydroxyquinoline are discrete.To further explore the structure-magnetic property relationships in depth,there must be more systematic magnetic research into 8-hydroxyquinoline-based complexes.Fourteen lanthanide complexes based on 8-hydroxyquinoline ligands were synthesized by adjusting the reaction conditions and changing the auxiliary ligands.The complexes have been characterized by X-ray single crystal diffraction,IR,TG,UV-vis,X-ray power diffraction.The fluorescent and magnetic properties of some complexes have been investigated.Single-crystal X-ray analysis reveals that complexes 1–7 are isomorphic dinuclear complexes,crystallizing in the same monoclinic space group P21/n.Complex 3 exhibits characteristic Tb(?)centered luminescence.Magnetic studies reveal that the maximum value of-?Sm for complex 2 is 15.00 J K-1 kg-1.Complex 4 shows slow magnetic relaxation behaviour with energy barrier of 4.25 K and the pre-exponential factors of 6.55×10-6 s.Complexes 8–9 are isomorphic dinuclear complexes,crystallizing in the same triclinic space group P1.Magnetic studies reveal that complex 9 shows slow magnetic relaxation behaviour with energy barrier of 9.61 K and the pre-exponential factors of 4.76×10-6 s.While Complexes 10–11 are non-isomorphic dinuclear complexes.Magnetic studies reveal that complex 11 shows slow magnetic relaxation behaviour with energy barrier of 31 K and the pre-exponential factors of 4.20×10-6 s.Complexes 4,9 and 11 exhibit different single molecule magnetic behavior due to their different coligands.Complexes 12–14 are isomorphic dinuclear complexes.Insterestingly,there exist in-situ ligand reaction in formation of lanthanide complexes.Magnetic studies reveal that complex 13 shows slow magnetic relaxation behaviour with energy barrier of 30.9 K and the pre-exponential factors of 1.95×10-6 s.