Two-dimensional metal–organic frameworks (MOFs) constructed from heterotrinuclear coordination units and 4,4′-biphenyldicarboxylate ligands

Three novel metal–organic frameworks (MOFs) formulated as [Zn₂M(BPDC)₃(DMF)₂]·4DMF (M = Co^II 1, Ni^II 2 or Cd^II 3; BPDC = 4,4′-biphenyldicarboxylate; DMF = N, N′-dimethylformamide) have been prepared via solvothermal synthesis from mixtures of the corresponding transition metal salts and 4,4′-biphenyldicarboxylic acid (H₂BPDC). The framework structures are characterized by single-crystal X-ray diffraction analysis, IR and UV-vis diffuse reflectance spectroscopy, thermogravimetric analysis (TGA), and X-ray powder diffraction (XRPD). All three compounds possess essentially the same 2-D layered coordination framework consisting of linear heterotrinuclear secondary building units (SBUs) connected by rigid bridging BPDC ligands. Crystal data: for 1 (C₆₀H₆₆CoN₆O₁₈Zn₂): monoclinic, space group P2₁/n, M = 1348.86, a = 20.463(4), b = 14.819(3), c = 23.023(5) Å, β = 111.75(3)°, V = 6484(2) ų, Z = 4, D_c = 1.382 Mg m⁻³. For 2 (C₆₀H₆₆N₆NiO₁₈Zn₂): monoclinic, space group P2₁/n, M = 1348.64, a = 11.670(2), b = 14.742(3), c = 19.391(4) Å, β = 102.29(3)°, V = 3259.5(11) ų, Z = 2, D_c = 1.374 Mg m⁻³. For 3 (C₆₀H₆₆CdN₆O₁₈Zn₂): monoclinic, space group P2₁/n, M = 1402.33, a = 11.491(2), b = 14.837(3), c = 19.386(4) Å, β = 101.53(3)°, V = 3238.3(11) ų, Z = 2, D_c = 1.438 Mg m⁻³.