title: A novel three-dimensional heterometalliccoordination polymer:poly[[hexaaquabis[mu3-3,5-dicarboxylatopyrazolato-kappa5O3,N2:N1,O5:O50]-(mu2-oxalato-kappa4O1,O2:O10,O20)-copper(II)dierbium(III)] trihydrate].
abstract: The title novel heterometallic 3d-4f coordination polymer, {[CuEr(2)(C(5)HN(2)O(4))(2)(C(2)O(4))(H(2)O)(6)].3H(2)O}(n), has a three-dimensional metal-organic framework composed of two types of metal atoms (one Cu(II) and two Er(III)) and two types of bridging anionic ligands [3,5-dicarboxylatopyrazolate(3-) (ptc(3-)) and oxalate]. The Cu(II) atom is four-coordinated in a square geometry. The Er(III) atoms are both eight-coordinated, but the geometries at the two atoms appear different, viz. triangular dodecahedral and bicapped trigonal prismatic. One of the oxalate anions is located on a twofold axis and the other lies about an inversion centre. Both oxalate anions act as bis-bidentate ligands bridging the latter type of Er atoms in parallel zigzag chains. The pdc(3-) anions act as quinquedentate ligands not only chelating the Cu(II) and the triangular dodecahedral Er(III) centres in a bis-bidentate bridging mode, but also connecting to Er(III) centres of both types in a monodentate bridging mode. Thus, a three-dimensional metal-organic framework is generated, and hydrogen bonds link the metal-organic framework with the uncoordinated water molecules. This study describes the first example of a three-dimensional 3d-4f coordination polymer based on pyrazole-3,5-dicarboxylate and oxalate, and therefore demonstrates further the usefulness of pyrazoledicarboxylate as a versatile multidentate ligand for constructing heterometallic 3d-4f coordination polymers with interesting architectures.
authors.affiliation: Applied Chemistry Department, School of Materials Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Ying-Zhong
authors.initials: YZ
authors.lastname: Shen