Two lanthanum(III) complexes containing η²-pyrazolate and η²-1,2,4-triazolate ligands: intra­molecular C—H...N/O inter­actions and coordination geometries

The lanthanum(III) complexes tris­(3,5-diphenyl­pyrazolato-κ²N,N′)tris­(tetra­hydro­furan-κO)lanthanum(III) tetra­hydro­furan monosolvate, [La(C₁₅H₁₁N₂)₃(C₄H₈O)₃]·C₄H₈O, (I), and tris­(3,5-diphenyl-1,2,4-triazolato-κ²N¹,N²)tris­(tetra­hydrofuran-κO)lanthanum(III), [La(C₁₄H₁₀N₃)₃(C₄H₈O)₃], (II), both contain La^III 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.

Binuclear and chain-structure zinc(II) complexes constructed from 3,4-di­meth­oxy-trans-cinnamic acid and N-donor coligands 4-(1H-pyrazol-3-yl)pyridine and 4,4′-bipyridine

3,4-Dimeth­oxy-trans-cinnamic acid (Dmca) reacts with zinc sulfate in the presence of 4-(1H-pyrazol-3-yl)pyridine (L₁) or 4,4′-bipyridine (L₂) under hydro­thermal conditions to afford two mixed-ligand coordination complexes, namely tetra­kis­(μ-3,4-dimeth­oxy-trans-cinnamato-κ²O:O′)bis­[[4-(1H-pyrazol-3-yl)pyridine]­zinc(II)] hepta­hydrate, [Zn₂(C₁₁H₁₁O₄)₄(C₈H₇N₃)₂]·7H₂O or [Zn₂(Dmca)₄(L₁)₂]·7H₂O, (I), and catena-poly[[bis­(3,4-dimeth­oxy-trans-cinnamato-κO)zinc(II)]-μ-4,4′-bipyridine-κ²N:N′], [Zn(C₁₁H₁₁O₄)₂(C₁₀H₈N₂)]_n or [Zn(Dmca)₂(L₂)]_n, (II). The Zn^II centres in the two compounds display different coordination polyhedra. In complex (I), the Zn^II cation is five-coordinated with a pseudo-square-pyramidal geometry, while in complex (II) the Zn^II cation sits on a twofold axis and adopts a distorted tetra­hedral coordination environment. Complex (I) features a centrosymmetric binuclear paddle-wheel-like structure, while complex (II) shows a chain structure. This study emphasizes the significant effect of the coordination mode of both carboxyl­ate-group and N-donor coligands on the formation of complex structures.

A tubular one-dimensional polymer constructed from alternating clusters of europium(III)-water and copper(I) chloride bridged by 4-(pyridin-4-yl)benzoate

A new 3d-4f heterometallic polymer, poly[[aqua-[mu]₃-chlorido-[[mu]₃-4-(pyridin-4-yl)benzoato]tris­[[mu]₂-4-(pyridin-4-yl)benzoato]dicopper(I)erbium(III)] dihydrate], {[Cu₂Er(C₁₂H₈NO₂)₄Cl(H₂O)]·2H₂O}_n, was synthesized by the hydro­thermal reaction of Er₂O₃, CuCl₂·2H₂O and 4-(pyridin-4-yl)benzoic acid in the presence of HClO₄. The asymmetric unit contains one Er³⁺ cation, two Cu⁺ cations, one Cl^- anion, four deprotonated 4-(pyridin-4-yl)benzoate ligands, one coordinated aqua ligand and two solvent water mol­ecules. This tubular one-dimensional polymer is constructed from alternating clusters of europium(III)-water and copper(I) chloride bridged by 4-(pyridin-4-yl)benzoate ligands. Extensive hydrogen-bonding inter­actions involving both the coordinated and the solvent water mol­ecules provide further stabilization to the structure.

A three-dimensional polymeric potassium complex of 5-sulfono­benzene-1,2,4-tri­carb­oxy­lic acid: poly[μ-aqua-aqua-μ₉-(2,4-dicarb­oxy-5-sulfonato­benzoato)-dipotassium(I)]

A three-dimensional polymeric potassium complex incorporating bridging water mol­ecules and 2,4-dicarb­oxy-5-sulfonato­benzoate ligands forms a one-dimensional inorganic chain with cage-like K₄(SO₃)₂ repeat units. The chains are bridged by carb­oxy­lic acid groups to form a two-dimensional layer, and these layers are further linked by carboyxlate groups and benzene rings to generate a three-dimensional framework.