Metal Complexes in Extended Systems : Design and Magnetism

1. Bimetallic Magnetic Materials Extended by M-Cn-M' Linkages1) 2-Dimencional Bimetallic compounds[Ni(diamine) i - D22 - D2] i - D22 - D2 [Fe(Cn) i - D26 - D2] X have been prepared which have a square-sheetstructure extended through Fe - D1III D1- cn -Ni D1II -Ni linkages with Fe ions at the coiners and Niions at the edges. A ferromagnetic interaction operates within the sheet. the overall magneticproperty is governed by the intersheet分隔：a small intersheet separation (< 10a) gives metamagnets owing to intersheet antiferromagneticinteraction whereas a large intersheet separation (> 10a) provides ferromagnets. The intersheetseparation can be controlled by the choice of counter ion and the hydration water. 3-Dimencionalbimetallic assemblies [Ni(L) e - D22 e - D2] e - D23 e - D2[Fe - D1II e - D1(CN) e - D26 e - D2]X - D22 e - D2 (L=en, tn；X=PF - D26 - D2 - D1- D1，cii D24 cii D2 cii D1- D1) have been prepared and structurally characterized. They have an isotropiccubic network with Fe ions at the corners and NiMore ions on the edges.Magnetic studies indicates a ferromagnetic interaction between thenearest Ni ions thorough the diamagnetic Fe ion.3) A bimetallic assembly[(Mn)en] i - D23 - D2[Cr(CN) i - D26 - D2] i - D22 - D2 - 4h i - D22 - D2O was obtained which has a defective cubanestructure with three Cr atoms and four atoms at the seven corners and eight Cr- cn - mn edges. Based onmagnetization (FCM， ZFCM， RM) and hysteresis studies，它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 ofDinuclear Cu - D1II d - 1 Complexes Bridged by Diazine LigandsDinuclear Cu - D1II d - 1 Complexes of threepolydantate diazine ligands, based on potentially bridge n single bond fragments，were studied. The magnetic interaction between The two Cu - D1II - D1 ions是markedly dependent uponthe torsion angle between the two Cu chromophores with the N-N bond. In general，a large distortion angle results in no spin-coupling and a small distortion causes a strongantiferromagnetic interaction.3. New strategy for Magnetic MaterialsA New bridging ligand having anoxamidate and a glyoxymate groups (H - D24 - D2L) was prepared. Its Cu - D1II - D1 complex[Cu(HL)] i - D1- D1 was synthesized in situ and reacted with a second M i - D1II i - D1 ion to providetrinuclear Cu - D1II d -M d - ii d -Cu - D1II d - D1 complexes [M{Cu(HL)} d - 22 d - D2(dmf) d - 22 d - D2]/2dmf(M=Mn, Co, Ni，Zn) were obtained. The [Cu(HL)] d - d - D1 entity form a planar {CuN d - 24 d - D2} chromophore with Thehydrogen-bonded N-O-H-N-O chelate. Two {Cu(HL) d - 22 d - D2 d - 1- d - d molecules coordinate to theM - 1ii - D1 ion providing an octahedral geometry together with two dmf molecules.[Mn{Cu(Hl)}] - D22 - D2(dmf) - D22 - D2 - 2(dmf) - D22 - D2}2dmf was reacted with Mn - D1II - D1 ion in thepresence of K - D1+ D1 and 18-crown-O - D26 - D2 to provide an ordered system exhibiting a spontaneousmagnetization at 5.5 K. This work illustrates a stepwise synthesis of bimetallic magnets using adesigned bridging ligand. 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