Metal Complexes in Extended Systems : Design and Magnetism

1.Bimetallic Magnetic Materials Extended by M-Cn-M‘Linkages 1)2-Dimencional bimetallic compounds[Ni(Diamine)I D 22 I D 2]I D 22 I D 2[Fe(Cn)I D 26 I D 2]X have been prepared which have a square-sheet structure extended through Fe I D 1 III I D 1-CN-Ni I D 1 II I D 1 linkages with Fe ions at the coiners and Ni ions at the edges.A ferromagnetic interaction operates within the sheet.The overall magnetic property is governed by the intersheet separation：a small intersheet separation(&lt；10)gives metamagnets owing to intersheet antiferromagnetic interaction whereas a large intersheet separation(&gt；10)provides ferromagnets.The intersheet separation can be controlled by the choice of counter ion and the hydration water.2)3-Dimencional bimetallic assemblies[Ni(L)I D 22 I D 2]I D 23 I D 2[Fe I D 1 II I D 1(CN)I D 26 I D 2]X I D 22 I D 2(L=en，tn；X=PF I D 26 I D 2 I D 1-I D 1，CIO I D 24 I D 2 I D 1-D 1)have been prepared and structurally characterized.They have an isotropic cubic network with Fe ions at the corners and Ni…More ions on the edges.Magnetic studies indicates a ferromagnetic interaction between the nearest Ni ions thorough the diamagnetic Fe ion.3)A bimetallic assembly[(Mn)en]I D 23 I D 2[Cr(CN)I D 26 I D 2]I D 22 I D 2 O was obtained which has a defective cubane structure with three Cr atoms and four atoms at the seven corners and eight Cr-CN-Mn edges.Based on magnetization(FCM，ZFCM，RM)and hysteresis studies，it was fount to be a ferrimagnet showing magnetic ordering below69K.To the best of our knowledge，the Tc is the highest among the structurally characterized molecular-based magnets.2。Magnetism of Dinuclear Cu I D 1 II文件D1 Complexes Bridged by Diazine LigandsDinuclear Cu I D 1 II文件D 1 complexes of three polydantate diazine ligands，based on potentially bridge N-N single bond fragments，were studied.The magnetic interaction between the two Cu I D 1 II I D 1 ions is markedly dependent upon the torsion angle between the two Cu chromophores with respect to the N-N bond.In general，a large distortion angle results in no spin-coupling and a small distortion causes a strong antiferromagnetic interaction.3。New strategy for Magnetic MaterialsA new bridging ligand having an oxamidate and a glyoxymate groups(H I D 24 Ii D 2 L)was prepared.Its Cu I D 1 II I D 1 complex[Cu(HL)]I D 1-I D 1 was synthesized in situ and reacted with a second M I D 1 II I D 1 ion to provide trinuclear Cu I D 1 II I D 1-M I D 1 II I D 1-Cu I D 1 II I D 1 complexes[M{Cu(HL)}I D 22 I D 2(Dmf)I D 22 I D 2]/2 dmf(M=Mn，Co，Ni，Zn)were obtained.The[Cu(HL)]I D 1 entity form a planar{CuN I D 24 I D 2}chromophore with the hydrogen-bonded N-O-H-N-O chelate.Two{Cu(HL)I D 22 I D 2 I D 1-I D 1 molecules coordinate to the M I D 1 II I D 1 ion providing an octahedral geometry together with two dmf molecules.[Mn{Cu(Hl)}]I D 22 I D 2(Dmf)I D 22 D 2 2(Dmf)I D 22 I D 2 D 2}2 dmf was reacted with Mn I D 1 II I D 1 ion in the presence of K I D 1 D 1 and 18-crown-O I D 26 I D 2 to provide an ordered system exhibiting a spontaneous magnetization at 5.5K.This work illustrates a stepwise synthesis of bimetallic magnets using a designed bridging and ligiging and.Less：Less

1. Bimetallic Magnetic Materials Extended by M-Cn-M' Linkages1) 2-Dimencional bimetallic compounds [Ni(diamine)ィイD22ィエD2]ィイD22ィエD2 [Fe(Cn)ィイD26ィエD2] X have been prepared which have a square-sheet structure extended through FeィイD1IIIィエD1-CN-NiィイD1IIィエD1 linkages with Fe ions at the coiners and Ni ions at the edges. A ferromagnetic interaction operates within the sheet. The overall magnetic property is governed by the intersheet separation : a small intersheet separation (<10 Å) gives metamagnets owing to intersheet antiferromagnetic interaction whereas a large intersheet separation (>10 Å) provides ferromagnets. The intersheet separation can be controlled by the choice of counter ion and the hydration water.2) 3-Dimencional bimetallic assemblies [Ni(L)ィイD22ィエD2]ィイD23ィエD2[FeィイD1IIィエD1(CN)ィイD26ィエD2]XィイD22ィエD2 (L=en, tn ; X=PFィイD26ィエD2ィイD1-ィエD1, CIOィイD24ィエD2ィイD1-ィエD1) have been prepared and structurally characterized. They have an isotropic cubic network with Fe ions at the corners and Ni … More ions on the edges.Magnetic studies indicates a ferromagnetic interaction between the nearest Ni ions thorough the diamagnetic Fe ion.3) A bimetallic assembly [(Mn)en]ィイD23ィエD2[Cr(CN)ィイD26ィエD2]ィイD22ィエD2 ・4HィイD22ィエD2O was obtained which has a defective cubane structure with three Cr atoms and four atoms at the seven corners and eight Cr-CN-Mn edges. Based on magnetization (FCM, ZFCM, RM) and hysteresis studies, it was fount to be a ferrimagnet showing magnetic ordering below 69 K. To the best of our knowledge, the Tc is the highest among the structurally characterized molecular-based magnets.2. Magnetism of Dinuclear CuィイD1IIィエD1 Complexes Bridged by Diazine LigandsDinuclear CuィイD1IIィエD1 complexes of three polydantate diazine ligands, based on potentially bridge N-N single bond fragments, were studied. The magnetic interaction between the two CuィイD1IIィエD1 ions is markedly dependent upon the torsion angle between the two Cu chromophores with respect to the N-N bond. In general, a large distortion angle results in no spin-coupling and a small distortion causes a strong antiferromagnetic interaction.3. New strategy for Magnetic MaterialsA new bridging ligand having an oxamidate and a glyoxymate groups (HィイD24ィエD2L) was prepared. Its CuィイD1IIィエD1 complex [Cu(HL)]ィイD1-ィエD1 was synthesized in situ and reacted with a second MィイD1IIィエD1 ion to provide trinuclear CuィイD1IIィエD1-MィイD1IIィエD1-CuィイD1IIィエD1 complexes [M{Cu(HL)}ィイD22ィエD2(dmf)ィイD22ィエD2]/2dmf (M=Mn, Co, Ni, Zn) were obtained. The [Cu(HL)]ィイD1-ィエD1 entity form a planar {CuNィイD24ィエD2} chromophore with the hydrogen-bonded N-O-H-N-O chelate. Two {Cu(HL)ィイD22ィエD2ィイD1-ィエD1 molecules coordinate to the MィイD1IIィエD1 ion providing an octahedral geometry together with two dmf molecules. [Mn{Cu(Hl)}]ィイD22ィエD2(dmf)ィイD22ィエD2・2(dmf)ィイD22ィエD2}2dmf was reacted with MnィイD1IIィエD1 ion in the presence of KィイD1+ィエD1 and 18-crown-OィイD26ィエD2 to provide an ordered system exhibiting a spontaneous magnetization at 5.5 K. This work illustrates a stepwise synthesis of bimetallic magnets using a designed bridging ligand. Less