Influence of Anionic Ligands (X) on the Nature and Magnetic Properties of Dinuclear LCuGdX₃·nH₂O Complexes (LH₂ Standing for Tetradentate Schiff Base Ligands Deriving from 2-Hydroxy-3-methoxybenzaldehyde and X Being Cl, N₃C₂, and CF₃COO)

The monometallic precursor L¹Cu (L¹H₂ standing for 1,3-bis((3-methoxysalicylidene)amino)-2,2‘-dimethylpropane) reacts with GdCl₃·6H₂O to afford a dinuclear complex which crystallizes in the orthorhombic space group Pca2₁ (No. 29) in a cell having the dimensions a = 9.0246(11) Å, b = 16.5198(14) Å, c = 20.286(2) Å, and Z = 4. Analysis of the structural data shows that it may be formulated as [L¹CuCl₂Gd(H₂O)₄]Cl·2H₂O. The cationic dinuclear unit possesses a CuO₂Gd bridging core which is almost planar. The complex displays a ferromagnetic interaction (10.1 cm^-1) which is the largest yet reported for a structurally characterized dinuclear (Cu−Gd) complex. Lower magnetic interactions are observed for neutral L¹CuGdX₃·H₂O complexes (X = N₃C₂, CF₃COO). Consideration of the magnetic and structural data obtained for various dinuclear (Cu−Gd) complexes leads to a correlation between the magnitude of the magnetic interaction and the exponential of the dihedral angle between the two halves of the CuO₂Gd bridging core.