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

Four lanthanide coordination polymers formulated as {[La(3)L(9)(H(2)O)(3)]EtOH(.)H(2)O}(n)1,{[Pr(2)L(6)(H(2)O)(2)]HL(.)H(2)O}(n)2,{[Dy(2)L(6)(H(2)O)]0.5HL(.)H(2)O}n 3 and {[Ho(2)L(6)(H(2)O)]0.5HL.H(2)O}(n) 4 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. (c) 2005 Elsevier B.V. All rights reserved.