Crystal structures of two one-dimensional coordination polymers constructed from Mn2+ ions, chelating hexafluoro-acetylacetonate anions, and flexible bipyridyl bridging ligands

Abstract

The syntheses and crystal structures of two one-dimensional coordination polymers, [Mn(C₅HO₂F₆)₂(C₁₆H₂₀N₂)]_n (1) and [Mn(C₅HO₂F₆)₂(C₂₀H₂₀N₂)]_n (2), are described, where C₅HO₂F₆⁻ is the hexafluoro acetylacetonate anion, C₁₆H₂₀N₂ is 1,6-bis(4-pyridyl)-hexane, and C₂₀H₂₀N₂ is 1,4-bis[2-(3-pyridyl)ethyl]-benzene. In both phases, the metal ion lies on a crystallographic twofold axis and is coordinated by two chelating C₅HO₂F₆⁻ anions and two bridging bipyridyl ligands to generate a cis-MnN₂O₄ octahedron. The bridging ligands, which are completed by crystallographic inversion symmetry in both compounds, connect the metal nodes into zigzag [20 1 ] chains in 1 and contorted [001] chains in 2. Intrachain C–H•••O interactions occur in 1 but not in 2, which may be correlated with the relative orientations of the ligands. Crystal data: 1, C₂₆H₂₂F₁₂MnN₂O₄, M_r = 709.40, monoclinic, C2/c (No. 15), a = 9.3475(2) Å, b = 16.6547(3) Å, c = 18.3649(4) Å, β = 91.1135(8)°, V = 2858.50(10) ų, Z = 4, R(F) = 0.030, wR(F²) = 0.075. 2, C₃₀H₂₂F₁₂MnN₂O₄, M_r = 757.44, monoclinic, C2/c (No. 15), a = 19.9198(2) Å, b = 10.6459(2) Å, c = 16.8185(3) Å, β = 119.8344(8)°, V = 3093.91(9) Å3, Z = 4, R(F) = 0.032, wR(F²) = 0.078.