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2 Polish Journal of Chemistry

2 2002

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Synthesis, Characterization and Magnetism of Fe(II)-Pd(II0-Fe(II) Heterotrinuclear Complexes Bridged by Dioximato Groups

Li Y., Yan C. -W., Zeng X.-C.

Polish Journal of Chemistry

2002

Vol. 76 / nr 5

645-652

Three new Fe(II)-Pd(II)-Fe(II) heterotrinuclear complexes with dioximato-bridge have been synthesized and identified as [Fe2Pd(_-FD)2(Me2-bpy)4]SO4 (1), [Fe2Pd(_-FD)2(Me2-phen)4]SO4 (2) and [Fe2Pd(_-FD)2(Me-phen)4]SO4 (3); where (_-FD)2_ represents _-furildioximato; Me2-bpy, Me2-phen and Me-phen denote 4,4_-dimethyl-2,2_-bipyridine; 2,9-dimethyl-1,10-phenanthroline (Me2-phen) and 5-methyl-1,10-phenanthroline (Me-phen). Based on elemental analyses, molar conductance measurements, IR and electronic spectral studies, these complexes are proposed to have extended dioximato-bridged structures and to consist of two iron(II) ions and a palladium(II) ion, in which the central palladium(II) ion has a square-planar environment and the end capped two iron(II) ions have a distorted octahedral environment. The magnetic properties of complexes [Fe2Pd(_-FD)2(Me2-bpy)4]SO4 (1) and [Fe2Pd(_-FD)2(Me2-phen)4]SO4 (2) were investigated over the 4.2~300Krange and correspond to what is expected for an antiferromagnetic Fe(II)-Fe(II) pair with SFe(II) = 2 and SPd(II) = 0 (Pd2+ is a diamagnetic in a square-planar environment) local spins. The exchange integral (J) was evaluated as J = _2.89 for (1) and J = _3.16 for (2) based on the spin Hamiltonian operator, _ _ _ H = JS S 1 2 _ _ 2 .

Synthesis and Magnetic Properties of mi-Oxalato-Bridged Cu(II)-Fe(III)-Cu(II) Heterotrinuclear Complexes

Wang H. D., Li Y. -T., Yan C. -W., Zeng X.-C.

Polish Journal of Chemistry

2002

Vol. 76 / nr 5

637-644

Three new _-oxalato-bridged copper(II)-iron(III)-copper(II) heterotrinuclear complexes described by the overall formula [Cu2Fe(ox)3L2]ClO4, where ox represents the oxalato dianions and L stands for 5-phenyl-1,10-phenanthroline (Ph-phen), 4,7-diphenyl- 1,10-phenanthroline (Ph2-phen) or 5-chloro-1,10-phenanthroline (Cl-phen), have been synthesized and characterized by elemental analyses, molar conductivity and magnetic moment (at room-temperature) measurements, IR and electronic spectral studies. It is proposed that these complexes have extended ox-bridged structures, consisting of two copper(II) and an iron(III) ions, in which the central iron(III) ion has an octahedral environment and the end capped two copper(II) ions have a square-planar environment. The variable-temperature susceptibilities of [Cu2Fe(ox)3(Ph-phen)2]ClO4 complex were measured and studied in the 4.2~300 K range. The least-squares fit of the experimental susceptibility based on the spin Hamiltonian operator, _ _ _ H = JS S 1 2 _ _ 2 , yielded J = -9.89 cm-1. The magnetic coupling parameter is consistent with an antiferromagnetic exchange interaction between the copper(II) and iron(III) ions through the oxalato-bridge in the complex.