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The lanthanum(III) complexes tris(3,5-diphenylpyrazolato-κ2 N, N′)tris(tetrahydrofuran-κ O)lanthanum(III) tetrahydrofuran monosolvate, [La(C15H11N2)3(C4H8O)3]·C4H8O, (I), and tris(3,5-diphenyl-1,2,4-triazolato-κ2 N1, N2)tris(tetrahydrofuran-κ O)lanthanum(III), [La(C14H10N3)3(C4H8O)3], (II), both contain LaIII atoms coordinated by three heterocyclic ligands and three tetrahydrofuran ligands, but their coordination geometries differ. Complex (I) has a mer-distorted octahedral geometry, while complex (II) has a fac-distorted configuration. The difference in the coordination geometries and the existence of asymmetric La-N bonding in the two complexes is associated with intramolecular C-H...N/O interactions between the ligands. [ABSTRACT FROM AUTHOR]

In the title compound, {[Zn(2)(C(16)H(4)I(2)O(8))(H(2)O)(4)]·2H(2)O}(n), two crystallographically independent Zn(II) atoms are each located on a twofold rotation axis. Both Zn(II) atoms are in distorted octa-hedral coordination geometries: one is coordinated by six O atoms from four carboxyl-ate groups, while the other is coordinated by two carboxyl-ate groups and four water mol-ecules. The tetra-carboxyl-ate ligand mol-ecules connect the Zn(II) atoms, completing a three-dimensional metal-organic framework. O-H⋯O hydrogen bonds link the metal-organic framework with the uncoord-inated water mol-ecules.

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.