Syntheses, Structures And Magnetic Properties Of New Lanthanide-based Complexes With Chelated Ligands

The study on the structures and magnetic properties of single-molecule magnets(SMMs) is a great challenge and a potential field in the future. In this paper, twelve new complexs have been synthesized by the slow diffusion reaction of lanthanide ions and H2 salen or bidentate chelated ligands with O-atom. These complexes included two tetranuclear clusters [Gd4(salen)6](1) and [Tb4(salen)6·4CH4O](2), one 14-nuclear cluster [Dy14(salen)6(C7H6O)6(CH3OH)2(H2O)20·2NO3·2H2O](3), single-ligand mononuclear complex [Ln(Ph2acac)3(H2O)](Ln = Er(4), Dy(5), Tb(6), Tm(7), Ho(8)), double-ligands mononuclear complex [Dy(Ph2acac)(terpy)(NO3)2·C3H6O](Ln = Dy(9), Tb(10), Ho(11)) and [Dy(Ph2acac)3(bpy)](12). These materials were characterized by single-crystal X-ray difraction, powder X-ray diffraction, infared spectra and thermogravitic analysis. The magnetic properties of some complexes have also been studied by magnetometer.For complexes 1-3 containing H2 salen ligand, the structures were influenced by the types of solvents and pH values. The antiferromagnetic coupling interaction and slow relaxation behavior of single molecule magnet were observed in complex 2.For the isostructuralmononuclear complexs 4-8 containing Ph2 acacH ligand, The antiferromagnetic coupling interactions were found in complexes 4 and 8. The slow relaxation behaviors of single molecule magnet for both complexes were not determined.For mononuclear complexs 9-12 containing Ph2 acacH and trepy(or bpy) ligands, complexes 9 and 10 are isostructural. The ferromagnetic interactions between lanthanide ions were observed in complexes 9, 10 and 12. In addition, complexes 9 and 10 show the slow magnetization relaxation behavior of single molecule magnet, and complex 12 is a single molecule magnet.