FERROMAGNETICALLY COUPLED GDIIICUII MOLECULAR MATERIAL

The compound Gd2(ox)[Cu(pba)]3[Cu(H2O)5].20H2O (1), where ox stands for oxalato and pba for 1,3-propylenebis(oxamato), has been synthesized. 1 crystallizes in the monoclinic system, space group C2/m. The lattice parameters are a = 21.186 (7) angstrom, b = 21.098 (2) angstrom, c = 15.079 (1) angstrom, and beta = 92.06 (2)-degrees, with Z = 4. The crystal structure consists of layers of double-sheet polymers separated by water molecules. A puckered ladderlike arrangement of Gd[Cu(pba)] units forms a two-dimensional honeycomb pattern connected by oxalato groups. Discrete [Cu(H2O)5]2+ entities are interspaced in the gap between the layers. The temperature dependence of the zero-field magnetic susceptibility down to 1.3 K and the field dependence of the magnetization in both the low-field regime (below 200 G) and the high-field regime (up to 20 T) have been investigated. The magnetic data are consistent with a rather strong spin correlation within the lattice and reveal that the Gd(III)-Cu(II) interaction through the oxamato bridge is ferromagnetic in spite of the large Gd...Cu separations (between 5.693 (1) and 5.739 (1) angstrom).