Structural and Magnetic Study of a Trinuclear MnII-GdIII-MnII Complex

The synthesis, structural determination and magnetic study of a trinuclear Mn-II-Gd-III-Mn-II complex involving a Schiff base ligand are described. The structural study demonstrates that the complex presents a linear arrangement of the Mn and Gd ions, with hexacoordinate Mn ions in slightly distorted or distorted trigonal prism environments and nine-coordinate gadolinium ions. The Mn and Gd ions are linked by two phenoxido bridges for one Mn-Gd subunit and two phenoxido plus one nitrato bridges for the other Mn-Gd subunit. Ferromagnetic interactions operate in the complex. The best fit takes into account two different J constants and D and E zero-field splitting terms. A strict 3d-5d(Gd) orthogonality is not possible in the present complex because all 3d orbitals of the Mn ions are occupied, which does agree with the weak value of the J(Mn,Gd) parameter. Oxidation of this complex does not yield the corresponding Mn-III-Gd-III-Mn-III entity. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)