Syntheses, structures and magnetic properties of nine coordination polymers based on terphenyl-tetracarboxylic acid ligands

Nine coordination polymers (CPs) [Mn(H3L)(H2L)(0.5)(phen)](n) (1), [Ni2L(phen)(2)(mu(2)-H2O)](n) (2), {[Mn2L(phen)(2)] center dot (DMA)(H2O)}(n) (3), {[Co2L(mu(2)-H2O)(mu(2)-DMA)] center dot DMF}(n) (4), [CoL0.5(H2O)(phen)](n) (5), {[Ni2L(mu(2)-H2O)(mu(2)-DMA)] center dot DMA}(n) (6), {[Co2L(mu(2)-H2O)(mu(2)-DMA)]center dot DMA}(n) (7), {[Ni2L(mu(2)-H2O)(H2O)(2)(DMF)(2)]center dot(H2O)(2)(DMF)} n (8), and {[Ni4L2(mu(2)-H2O) (4)(H2O)(2)]center dot(H2O)(2)(NMP)}(n) (9) (H4L = 1,1': 4', 1 ''-terphenyl-2', 4,4 '', 5'-tetracarboxylic acid, DMA = N, N-dimethylacetamine, DMF = N, N-dimethylformamide, NMP = N-methyl-2-pyrrolidone, phen = 1,10-phenanthroline) have been synthesized and structurally characterized. Crystal structural analyses reveal that 1 features the uninodal 2D (4,4) network with the dinuclear Mn-2(COO)(2) units as 4-connected nodes. 3 and 5 possess the binodal 2D (4,4) network with dinuclear Mn-2(COO)(4)/Co2O2 units and L4- ligands as 4-connected nodes, respectively. In 2 and 8, each dinuclear Ni-2(COO)(2)(mu(2)-H2O) unit links to four L4- ligands and each L4- ligand bridges four dinuclear Ni-2(COO)(2)(mu(2)-H2O) units to generate the 3D framework, which can also be rationalized as a binodal 4,4-connected (4(2).8(4))(4(2).8(4)) topological network by considering the dinuclear Ni-2(COO)(2)(mu(2)-H2O) units as non-planar 4-connected nodes and L4- ligands as planar 4-connected nodes, respectively. In 4, 6-7 and 9, there exist a series of parallel-aligned metal-carboxylate chains, which are linked along two directions by paraterphenyl moieties of L4- ligands to generate the 3D frameworks. Moreover, direct current magnetic susceptibility measurements were carried out to study their magnetic properties. In complexes 2 and 9, weak ferromagnetic interactions between the magnetic centers were observed. In addition, the other compounds show weak antiferromagnetic exchange interactions between the adjacent metal ions.