Two Hydroxo Bridged Dinuclear Lanthanide Phen Complexes: [Ln2(phen)4(H2O)4(OH)2](phen)2(NO3)4 with Ln = Tm, Yb
2014
Wei, Dan-Yi | Zheng, Yue-Qing | Lin, Jian-Li
Two isostructural hydroxo bridged dinuclear lanthanide phen complexes of general composition [Ln₂(phen)₄(H₂O)₄(OH)₂](phen)₂(NO₃)₄ with Ln = Tm (1), Yb (2) were prepared by reactions of the corresponding lanthanide nitrate and phenanthroline monohydrate in CH₃OH/H₂O at pH = 5.5. They crystallize in the triclinic space group P1̄ (no. 2) with the cell dimensions: a = 11.233(1), b = 11.456(1), c = 14.011(2) Å , α = 93.91(1)°, β = 98.20(1)°, γ = 108.21(1)°, V = 1683.0(3)ų, Z = 1 for 1 and a = 11.236(1), b = 11.480(2), c = 13.986(2)Å , α = 93.91(1)°, β = 98.17(1)°, γ = 108.33(1)°, V = 1682.9(3) ų, Z = 1 for 2. The crystal structures are composed of the hydroxo bridged dinuclear [Ln₂(phen)₄(H₂O)₄(OH)₄]⁴⁺ complex cations, hydrogen bonded NO₃⁻ anions and π-π stacking (phen)₂ dimers. The lanthanide atoms are each surrounded by two phen ligands, two H₂O molecules and two μ-OH groups to complete a tetragonal antiprismatic LnN₄O₄ coordination. Via two common μ-OH groups, two neighboring tetragonal antiprisms are condensed to form a centrosymmetric dinuclear [Ln₂(phen)₄(H₂O)₄(OH)₄]⁴⁺ complex cation. The complex cations and (phen)₂ dimers are assembled via π-π stacking interactions and hydrogen bondings into 2D layers parallel to (101̄), between which the hydrogen bonded NO₃⁻ anions are sandwiched. The Tm compound shows paramagnetic behavior with an experimental magnetic moment of 7.51 μB at room temperature. No magnetic ordering is evident down to 5 K. Over the temperature range 70 - 300 K, the Yb compound obeys the Curie-Weiss law with an experimental magnetic moment of 4.32 μB at room temperature and shows weak ferrimagnetic behavior at low temperature.
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