Crystal structure and magnetic properties of lanthanide-trans-2-butenoate polymers (Ln = La, Pr, Dy, Ho)

Four lanthanide coordination polymers formulated as {[La3L9(H2O)3]EtOH · H2O}n1, {[Pr2L6(H2O)2]HL · H2O}n2, {[Dy2L6(H2O)]0.5HL · H2O}n3 and {[Ho2L6(H2O)]0.5HL · H2O}n4 and HL = trans-2-butenoic acid have been synthesized from the corresponding pure lanthanide oxide and HL acid in water at pH 3. The compounds were characterized by chemical analysis, IR spectroscopy, thermogravimetry, variable-temperature magnetic susceptibility and single crystal X-ray diffraction studies. A common feature in these materials is the presence of two differentiated lanthanide nodes linked by carboxylates into extended chains. These are further connected by inter- and intra-molecular hydrogen-bonds involving ligand and solvate molecules. Weak ferromagnetic interactions appear to be operative in the Dy material.