Synthesis and magnetic property of copper(II)-lanthanide(III) complexes [{CuIILLnIII(o-van)(CH3COO)(MeOH)}2]•2H2O (LnIII = GdIII, TbIII, and DyIII;: H3L=1-(2-hydroxybenzamido)-2-(2-hydroxy-3-methoxybenzylideneamino)ethane;: o-van=3-methoxysalicylaldehydato)

Three tetranuclear copper(II)-lanthanide(III) complexes, [{Cu(II)LLn(III) (o-van)(CH3COO)(MeOH)}(2)]center dot 2H(2)O (Ln(III) = Gd-III, Tb-III, and Dy-III), were synthesized and characterized, where H3L is 1-(2-hydroxybenzamido)-2-(2-hydroxy-3-methoxybenzylideneamino)ethane and o-van is 3-methoxysalicylaldehydato. These compounds are isomorphous to each other and consist of a cyclic tetranuclear Cu(2)(II)Ln(2)(III) structure, in which the Cu-II and Ln(III) ions are alternately arrayed and the Cu-II component complex. [(CuL)-L-II](-) unit functions as a "bridging ligand-complex" between two adjacent Ln(III) ions through the phenolato and methoxy oxygen atoms at one side and the amido oxygen atom at the another side. The temperature-dependent magnetic susceptibilities from 2.0 to 300.0 K and the field-dependent magnetizations at 2.0 K from 0 to 5 T showed that the magnetic interaction between Cu-II and each of the lanthanide ions is ferromagnetic. The magnetic susceptibilities of [{(CuLGdIII)-L-II (o-van)(CH3COO)(MeOH)}(2)]center dot 2H(2)O were analyzed by using a spin-only Hamiltonian H = -2J(1) (S-Cul S-Gd1 + SCu2SGd2) - 2J(2)(SCu1SGd2 + SCu2SGd1) based on a cyclic tetranuclear structure and gave the best-fit parameters of g = 1.97, J(1) = +3.8 cm(-1), J(2) = +0.7 cm(-1), and zJ' = -0.01 cm(-1). The magnetization data at 2.0 K of [(Cu-II LGdIII (o-van)(CH3COO)(MeOH))(2)]center dot 2H(2)O were well reproduced by using a Brillouin function with an S = 8 spin ground state due to the ferromagnetic interactions between Cu-II and Gd-III ions and g = 1.97. The ac magnetic susceptibilities of [(Cu(II)LLn(III)(o-van)(CH3COO)(MeOH))(2)]center dot 2H(2)O (Ln(III) = Tb-III and Dy-III) in the temperature range 1.8-10.0 K with a 3 G ac field oscillating in the range 1-1000 Hz showed a frequency dependence characteristic of SMMS.