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1

Synthesis and Magnetic Studies of Copper(II)-Iron(II) Heterodinuclear Complexes with N,N'-Bis[2-dimethylamino)ethyloxamido Dianion as Ligand

Li Y., Yan C., Lou J., Zhu C.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 5

635-644

EN

Three new copper(II)-iron(II) heterodinuclear complexes bridged by the dianions of N,N_-bis[2-(dimethylamino)ethyl]oxamido (dmoxae) and end-capped with 2,2_-bipyridine (bpy); 1,10-phenanthroline (phen) or 5-nitro-1,10-phenanthroline (NO2phen); namely [Cu(dmoxae)Fe(bpy)2]SO4 (1), [Cu(dmoxae)Fe(phen)2]SO4 (2) and [Cu(dmoxae)Fe(NO2phen)2]SO4 (3), have been synthesized and characterized. The three dinuclear complexes have not yet been isolated in crystalline form suitable for X-ray structure analysis, but based on elemental analyses, IR and electronic spectra studies, magnetic moments at room-temperature and molar conductivity measurements, these complexes are proposed to have an extended oxamido-bridged structure consisting of planar copper(II) and octahedral iron(II) ions. The [Cu(dmoxae)Fe(bpy)2]SO4 (1) and [Cu(dmoxae)Fe(phen)2]SO4 (2) complexes have been further characterized by variable temperature magnetic susceptibility (4.2~300 K) and the observed data were least-squares fitted to the susceptibility equation derived from the spin Hamiltonian including single-ion zero-field interaction for the iron(II) ion, _H =-2J_S1_ _ S2 - D_SZ1 2 , giving the exchange integrals J = -20.9 cm-_ for (1) and J = -22.7 cm-1for (2). These results indicated that the spin coupling between the adjacent copper(II) and iron(II) ions through the oxamido-bridge in both complexes (1) and (2) is antiferromagnetic. The influence of methyl substituents in the amine groups of the bridging ligand and the relative stability of the chelate ring arrangement around the copper(II) on magnetic interactions between the metal ions of this kind of complexes is also discussed.

2

Synthesis and Magnetic Analysis of mi-Oxamido-Bridged Copper(II)-Iron(II) Heterodinuclear Complexes

Li Y., Yan C. -W., Guan H. -S.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 2

137-145

EN

Five new copper(II)-iron(II) heterodinuclear complexes bridged by the dianion of N,N_-bis[3-(dimethylamino)propyl]oxamido (dmoxpn) and end-capped with 2,2_-bipyridine (bpy); 1,10-phenanthroline (phen); 5-nitro-1,10-phenanthroline (NO2-phen); 5-chloro-1,10-phenanthroline (Cl-phen) or 5-bromo-1,10-phenanthroline (Br-phen); namely [Cu(dmoxpn)FeL2](ClO4)2 (L = bpy, phen, NO2-phen, Cl-phen, Br-phen), have been synthesized and characterized. Based on elemental analyses, magnetic moments (at room temperature), molar conductivity measurements, and spectroscopic studies, extended oxamido-bridged structures consisting of a copper(II) ion and an iron(II) ion, which have a square-planar environment and an octahedral environment, respectively, are proposed for these complexes. The [Cu(dmoxpn)Fe(bpy)2](ClO4)2 (1) and [Cu(dmoxpn)Fe(phen)2](ClO4)2 (2) complexes have been further characterized by variable temperature magnetic susceptibility (4.2~300 K) and the observed data were least-squares fitted to the susceptibility equation derived from the spin Hamiltonian including single-ion zero-field interaction for the iron(II) ion,_ _ _ _ H = 2JS S DS 1 2 Z1 2 Ĺ , giving the exchange integrals J = -15.9 cm-1 for (1) and J = -17.5 cm-1 for (2). These results indicated that the spin coupling between the adjacent copper(II) and iron(II) ions through oxamido-bridge in both complexes (1) and (2) is antiferromagnetic. The influence of methyl (-CH3) substituents in the bridging ligand on magnetic interactions between the metal ions of this kind of complexes is also discussed.

3

Synthesis, Characterization and Magnetism of Heterodinuclear Cu(II)-Fe(II) Complexes Bridged by N,N'-Oxamidobis(propionato)cuprate(II)

Li Y., Yan C., Zeng X.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 8

1063-1070

4

Synthesis , characterization and magnetic studies of my-oxamido heterodinuclear copper(II)-iron(II) complexes

Li Y.T., Yan C.W., Kong X.H.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 9

2052-2059

EN

Six new my-oxamido heterodinuclear complexes, [Cu(Me2oxpn)Fe(L)2]SO4, have been synthesized from the planar monomeric fragment [Cu(Me2oxpn)], where Me2oxpn denotes N,N'-bis(3-amino-2,2-dimethylpropyl)oxamido dianion and L represents 1,10-phenanthroline(phen);5-nitro-1,10-phenanthroline (NO2-phen); 5-chloro-1,10-phenanthroline (Cl-phen); 5-bromo-1,10-phenanthroline (Br-phen); 5-methyl-1,10-phenanthroline (Me-phen) and 2,2'-bipyridine (bpy). Based on the elemental analyses, spectroscopic studies, magnetic moments (at room temperature) and molar conductivity measurements, extended oxamido-bridges structures consisting of a copper(II) and an iron(II) ions, which have a square planar environmental and an octahedral environment, respectively, are proposed for these complexes. The [Cu(Me2oxpn)Fe(bpy)2]SO4 (1) and [Cu(Me2oxpn)Fe(phen)2]SO4 (2) complexes have been characterized by variable temperature magnetic susceptibility (4.2-300 K) and the oberved data were least-squares fitted to the susceptibility equation derived from the spin Hamiltonian including single- ion zero-field interaction for the iron(II) ion, H=-2JS1 x S2 - DS(2)-Zl, giving the exchange integrals J=-15.8 cm(-1) for (1) and J=-17.6 cm(-1) for (2). These results indicated that the spin coupling between the adsjacent copper(II) and iron(II) ions through oxamido-bridge in both complexex (1) and (2) is antiferromagnetic.