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

Nine coordination polymers (CPs) [Mn(H3 L)(H2 L)0.5 (phen)]n (1), [Ni2 L(phen)2 (μ2 -H2 O)]n (2), {[Mn2 L(phen)2 ]·(DMA)(H2 O)}n (3), {[Co2 L(μ2 -H2 O)(μ2 -DMA)]·DMF}n (4), [CoL0.5 (H2 O)(phen)]n (5), {[Ni2 L(μ2 -H2 O)(μ2 -DMA)]·DMA}n (6), {[Co2 L(μ2 -H2 O)(μ2 -DMA)]·DMA}n (7), {[Ni2 L(μ2 -H2 O)(H2 O)2 (DMF)2 ]·(H2 O)2 (DMF)}n (8), and {[Ni4 L2 (μ2 -H2 O)4 (H2 O)2 ]·(H2 O)2 (NMP)}n (9) (H4 L = 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 Mn2 (COO)2 units as 4-connected nodes. 3 and 5 possess the binodal 2D (4,4) network with dinuclear Mn2 (COO)4 /Co2 O2 units and L4- ligands as 4-connected nodes, respectively. In 2 and 8, each dinuclear Ni2 (COO)2 (μ2 -H2 O) unit links to four L4- ligands and each L4- ligand bridges four dinuclear Ni2 (COO)2 (μ2 -H2 O) units to generate the 3D framework, which can also be rationalized as a binodal 4,4-connected (42 ·84 )(42 ·84 ) topological network by considering the dinuclear Ni2 (COO)2 (μ2 -H2 O) 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 para-terphenyl 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.