Six new coordination polymers based on a tritopic pyridyldicarboxylate ligand: structural, magnetic and sorption properties

Using a rigid ligand, pyridine-3,5-bis(phenyl-4-carboxylic) acid (H2L), six new coordination polymers have been synthesized under solvothermal conditions, formulated as [Co(L)(DMF)] (1), [Co(L)(H2O)]center dot DMF (2), [Co-3(L)(2)(HCOO)(2)(H2O)(2)] (3), [Co-5(L)(4)(OH)(2)(H2O)(2)]center dot 0.5DMF center dot H2O (4), [Mn(L)(H2O)]center dot DMF (5), and [Zn(L)]center dot DMF (6) (DMF = N,N-dimethylformamide). Complex 1 exhibits a 2D layer structure with a four-connected net. 2 is also a 2D layer net which forms a 2D stacked layers porous framework through hydrogen bonding interactions. In 3, 10-connected clusters [Co-3(COO)(6)] are extended by a L2- linker to construct a 3D (3,10)-connected framework with a (4.6.8)(4(2).6(2).8(10).10) topology net. As for 4, a rare pentanuclear cluster, [Co-5(mu(3)-OH)(2)(COO)(8)N-4], serves as a 12-connected node to give a 3D (3,12)-connected framework with a larger solvent accessible volume. 5 shows a 2D 4(4) layer framework by considering Mn(II) as a four-connected node. 6 exhibits a 3D framework based on 1D Zn-(COO)-Zn chains. All complexes have been characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, thermogravimetric analysis and powder X-ray diffraction measurements. The magnetic properties of complexes 1-5 and the photoluminescence properties for 6 have been investigated. H-2, N-2 and CO2 adsorption measurements were carried out for 4.