Synthesis, crystal structure and magnetic properties of a novel GdIII-CuII heterodinuclear complex

Preparation, crystal structure and magnetic properties of a heterodinuclear complex, LCu(Me2CO)Gd(NO3)(3) (L = (N,N'-bis(3-methoxysalicylidene)propane-1,2-diamine) are reported. The crystal structure of the complex was determined by X-ray diffraction methods at 200 K. (C19H22N2O4)Cu(C3H6O)Gd(NO3)(3), monoclinic, space group P2(1)/c, with a = 9.795(9), b = 18.763(3), c = 15.579(2) Angstrom, beta = 95.297(2) V = 2850.9(7) Angstrom (3) 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 Gd . . . Cu separation is 3.425(3) Angstrom and the dihedral angle between the GdO(1)Cu and GdO(2)Cu planes is 164.8 degrees. 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 = -JS(Cu+)S(Gd)), giving the exchange integral J(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.