Extended Structures and Magnetic Properties of Lanthanide–Copper Complexes with Picolinic Acids as Bridging Ligands

Abstract

AbstractThe first examples of 3d–4f heterometallic complexes containing picolinic acid ligands were synthesized and characterized. Three series of complexes were obtained by the reaction of presynthesized “metallo ligands” Cu(pic)2 and Ln(ClO4)3 in 2:1, 3:1, and 4:1 mole ratios. Complexes 1–3 (denoted as the first series), [LnCu2(pic)4(H2O)6](ClO4)3·H2O (Ln = Sm, Nd, and Pr), are isomorphous and exhibit infinite 1D zigzag chain structures with rare earth ions in tricapped trigonal prismatic coordination. Complexes 4–10 (denoted as the second series), [Ln2Cu5(pic)10(H2O)8](ClO4)6·2H2O (Ln = Gd, Nd, Sm, Dy, Eu, Pr, and Yb), are isomorphous too, and exhibit extended 2D layered structures constituted by Cu(pic)2 moieties bridging the zigzag chains. Complex 11 (denoted as the third‐type complex), {NdCu(pic)2[CO(NH2)2]4(H2O)3}(ClO4)3·[Cu(pic)2]2, exhibits another type of nearly linear chain structure with additional Cu(pic)2 moieties trapped in the lattice by hydrogen bonds. Temperature‐dependent magnetizations of complexes 2–4, 6, and 11 indicate that these complexes follow the Curie–Weiss paramagnetic behavior down to 5 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)