Syntheses and structures of three novel 1-D lanthanide-isonicotinate coordination polymers

Three novel lanthanide-IN coordination polymers [Ln(IN)₃(H ₂O)₂]_n (Ln = Sm 1, Dy 2, Eu 3; IN = isonicotinate) have been hydrothermally synthesized and characterized by FT-IR spectra, elemental analysis and TG analysis. Single-crystal X-ray diffraction shows that 1, 2 and 3 are isostructural. Crystal data for 1: monoclinic, space group C2/c, a = 15.8384(14), b = 14.2662 (12), c = 9.5073(7) Å, β = 97.705(4)°, V = 2128.8(3) Å Z = 4, D_c= 1.724 g/cm ³, F(000) = 1084, μ = 2.806 mm^-1 and R = 0.0226; Crystal data for 2: monoclinic, space group C2/c, a = 15.7890(3), b = 14.1356(6), c = 9.5152(3) Å, β = 97.899(2)°, V = 2103.52(12) Å Z = 4, D_c = 1.784 g/cm³, F(000) = 1100, μ = 3.601 mm^-1 and R = 0.0406; Crystal data for 3: monoclinic, space group C2/c, a = 15.802(5), b = 14.242(4), c = 9.513(3) Å, β = 97.695(5)°, V = 2121.8(10) ų, Z = 4, D_c = 1.735 g/cm³, F(000) = 1088, μ = 3.004 mm^-1 and R = 0.0273. In the three compounds, the Ln(III) centers are eight-coordinated with antiprismatic geometry. The Ln(IN)₃(H₂O)₂ unit connects mutually to form a one-dimensional double zigzag chain via isonicotinate oxygen bridging. The infinite chains are further linked by inter-chain hydrogen-bonding to form a three-dimensional supramolecular network.