Synthesis and structures of carboxylate-bridged polynuclear copper(II)–lanthanide(III) complexes [CuLn(C5H5N+CH2CO2−)5(H2O)5][ClO4]5·2H2O (Ln = La or Nd) and [Cu3Nd2(C5H5N+CH2CO2−)10(NO3)2(H2O)8][ClO4]10·4H2O

Abstract

Two types of carboxylate-bridged copper(II)–lanthanide(III) complexes, [CuLn(C5H5N+CH2CO2–)5(H2O)5][ClO4]5· 2H2O 1 (LnIII = LaIII a or NdIII b) and [Cu3Nd2(C5H5N+CH2CO2–)10(NO3)2(H2O)8][ClO4]10·4H2O 2, have been synthesized and characterized by X-ray structural analysis. Complexes 1a and 1b are isomorphous. In both, a CuII atom is quadruply bridged to a LnIII atom by four µ-carboxylate groups at the basal positions, and co-ordinated by an aqua ligand at the apical position to form a square-pyramidal CuO4(OH2) geometry, while the LnIII atom is co-ordinated in a monocapped square antiprism by five carboxy oxygen atoms and four aqua ligands. In 2, a pair of CuII atoms in two centrosymmetrically related tetrakis(µ-carboxylate)-bridged dinuclear CuIINdIII subunits is each linked to the central CuII atom by a single syn-antiµ-carboxylate bridge, resulting in a pentanuclear cation. The central CuII atom is co-ordinated by two carboxy oxygen atoms and two aqua ligands in a distorted square-planar fashion; the other two CuII atoms adopt the same square-pyramidal geometry, each being ligated by the four oxygen atoms from the quadruple carboxylate bridges at the basal plane and by one oxygen atom of the syn-antiµ-carboxylate group at the apical position. The NdIII atom is co-ordinated in a distorted monocapped square antiprism by the four carboxy oxygen atoms, three aqua ligands and a chelate nitrate group.