Series Of Polynuclear Chromium-Lanthanide Heterometallic Complexes:Syntheses, Structures And Magnetic Properties

Recently, single-molecule magnets (SMMs), especially those based on3d-4f clusters have drawn lots of attentions in the fields of chemistry, physics and materials, owning to its potential applications in the storage and processing of information. Herein with the aim of design and synthesis of new3d-4f SMMs, some Cr-Ln complexes with glycine (Gly) and2,2’-dipyridyl (dipy) as ligands were prepared and their magnetic properties were characterized.(1) The research progress of3d-4f SMMs and Cr-Ln heterometallic clusters were summarized.(2) With glycine as ligand, six complexes, Na2[Ln3Cr(HGly)6(μ3-OH)4(H20)9]·(Cl4)10·18H20(Ln=Gd (1), Tb (2), Dy (3)), Na3[Gd3Cr2(HGly)6(μ3-OH)6(H2O)9]·(ClO4)11·Cl·28H2O (4), Na3[Tb3Cr2(HGly)6(μ3-OH)6(H2O)9]·(ClO4)6Cl6·6H2O (5) and Na3[Dy3Cr2(HGly)6(μ3-OH)6(H2O)9]·(ClO4)8·Cl4·14H2O (6) were synthesized. Structural analysis shows1-3have a{Ln3Cr} trigonal pyramidal skeleton and4-6have a {Ln3Cr2} compressed trigonal dipyramidal skeleton. Magnetic measurements indicate that1is antiferromagnetically coupled,3,5and6are ferromagnetically coupled, and5and6exhibit single-molecule magnet behavior. The two terminal water molecules of6can be substituted by two mono-coordinated4,4’-dipyridyl-N, N’-dioxide (dpyo) molecules to afford [Dy3Cr2(HGly)6(dpyo)2(μ3-OH)6(H2O)7]·(ClO4)9·15H2O (7) bearing3D π-π interacted cds network. Magnetic analysis shows that7also displays slow relaxation of the magnetization.(3) With dipy as ligand, two heterodinuclear clusters [LnCr(OH)2(dipy)2(H2O)6](ClO4)4-2H2O (Ln=Gd (8), Dy (9)), and three heterotrinuclear clusters [GdCr2(dipy)4(OH)4(H2O)4](ClO4)5·H2O (10),[LnCr2(dipy)4(OH)4(H2O)3.5(ClO4)](C1O4)4·H2O(Ln=Tb (11), Dy (12)) were synthesized. Magnetic studies show that9possesses strong ferromagnetism. Heterotetranuclear clusters [LnCr2(OH)4(dipy)4(H2O)(DMF)2Fe(CN)6]2[Fe(CN)6](C1O4)·xDMF·yH2O (Ln=Gd (13), x=4, y=47; T (14), x=5, y=42), whose magnetic properties are studied, were synthesized by the reaction of10and11with K3[Fe(CN)6].(4) The assembly role of the compounds was summarized.