Synthesis, Crystal Structure and Magnetic Properties of a Novel Gdm-Cun Heterodinuclear Complex

Z. Naturforsch. 55 b, 1131-1136 (2000); received July 24, 2000 Heterodinuclear Complex, Super-Exchange Interactions, Lanthanides Preparation, crystal structure and magnetic properties of a heterodinuclear complex, LCu(Me2C0 )Gd(N03)3 (L = (N,N'-bis(3-methoxysalicylidene)propane1,2-diamine) are re­ ported. The crystal structure of the complex was determined by X-ray diffraction methods at 200 K. (Ci9H22N20 4 )Cu(C3H6 0 )Gd(N0 3 )3, monoclinic, space group P2i/c, with a = 9.795(9), b = 18.763(3), c = 15.579(2) A, ß = 95.297(2) V = 2850.9(7) A3 and Z= 4. The central region of the complex is occupied by Cu(II) and Gd(III) ions which are bridged by two phenolato oxygen atoms of the ligand. The copper ion adopts a square-based 4+1 coordination mode, the equatorial N2O2 donors being afforded by the ligand while the axial position is occupied by an oxygen atom of the acetone molecule. The Gd(III) ion is deca-coordinated. In addition to the two phenolate oxygen atoms, the coordination sphere contains two oxygen atoms of the OMe side arms of L and six oxygen atoms from the three bidentate nitrate ions. The G d... Cu separation is 3.425(3) A and the dihedral angle between the GdO(l)Cu and GdO(2)Cu planes is 164.8°. The magnetic susceptibility of the complex was measured over the range 5 350 K and the observed data were successfully simulated by the equation based on the spin-Hamiltonian operator (H = -/SorSGd), giving the exchange integral 7(Cu-Gd) = 5.6(1) cm-1. This indicates a weak ferromagnetic spin exchange interaction. The nature of the magnetic super-exchange interaction of the title compound is compared with similar [Gd(III)-Cu(II)] heterodinuclear complexes.