Syntheses, Characterizations, and Properties of Six Metal-Organic Complexes Based on Flexible Ligand 5-(4-Pyridyl)-methoxyl Isophthalic Acid

Six new metal-organic frameworks have been synthesized under hydrothermal conditions, in H2O or DMF/H2O namely, [CoL](n) (1), [Ni2L2(H2O)](n) (2), [CoL(bimx)(1/2)](n) (3), [MnL(bimx)(1/2)](n) (4), [MnL(bimx)(1/2)](n) (5), {[CoL2(bimb)(H2O)(2)]center dot 2H(2)O}(n) (6) (bimx = 1,4-bis(imidazol-l-ylmethyl)benzene, bimb = 4,4'-bis(imidazol-l-ylmethyl)biphenyl, H2L = 5-(4-pyridyl)-methoxyl isophthalic acid). These complexes were characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Complex I reveals a 2-fold interpenetrating three-dimensional (3D) framework with rutile {4.6(2)}2{4(2).6(10).8(3)} topology. Complex 2 possesses a 3D 4-fold interpenetrating framework with ths topology. In complexes 3, 4 and 5, H2L and bimx ligands link Co, Ni and Mn cations to generate 3D frameworks. Compound 6 possesses a 3D interlocked structure, with 2D structures intercatenating each other into a 3D structure (2D + 2D -> 3D) and with new topology. In addition, thermal stabilities, photochemical properties, and the magnetic properties for 1, 3, 4, and 5 are also discussed in detail.