Anilato-Based Coordination Polymers with Slow Relaxation of the Magnetization: Role of the Synthetic Method and Anilato Ligand

We have prepared and characterized three coordination polymers formulated as [Dy2(C6O4Cl2)3(fma)6] & sdot; 4.5fma (1) and [Dy2(C6O4X2)3(fma)6] & sdot; 4fma & sdot; 2H2O with X=Br (2) and Cl (3), where fma=formamide and C6O4X22-=3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone dianion with X=Cl (chloranilato) and Br (bromanilato). Compounds 1 and 3 are solvates obtained with slow and fast precipitation methods, respectively. Compounds 2 and 3 are isostructural and only differ in the X group of the anilato ligand. The three compounds present (6,3)-gon two-dimensional hexagonal honey-comb structures. Magnetic measurements indicate that the three compounds show slow relaxation of the magnetization at low temperatures when a continuous magnetic field is applied, although with different relaxation times and energy barriers depending on X and the crystallisation molecules. Compounds 1-3 represent the first examples of anilato-based lattices with formamide and field-induced slow relaxation of the magnetization. The anilato-based DyIII-containing compounds formulated as [Dy2(C6O4Cl2)3(fma)6] & sdot; 4.5fma (1) and [Dy2(C6O4X2)3(fma)6] & sdot; 4fma & sdot; 2H2O, with X=Br (2) and Cl (3), prepared with formamide as coordinating solvent, are coordination polymers with a honey-comb layered structure showing slow magnetic relaxation when a DC field is applied. Compounds 1 and 3 are solvates obtained with a slow and fast crystallization method, respectively. Compounds 2 and 3 are isostructural. image