Coordination Frameworks Containing Flexible Long-Spanning Dipyridine Ligands and Aromatic Dicarboxylic Ligands Bridged Cobalt(II)/Nickel(II): Syntheses, Structures, UV–Vis DRS and Magnetic Properties.

Four new coordination frameworks with formulas of {[Co(fdca)(4-bpmp)(H2O)2]·2H2O}n (1), {[Ni(fdca)(4-bpmp)(H2O)2]·2H2O}n (2), [Co(tdca)(4-bpmp)(H2O)]n (3) and [Co(fuma)(4-bpmp)(H2O)2]n (4) [4-bpmp = bis (4-pyridylmethyl)piperazine, fdca = 2,5-furandicarboxylic acid, tdca = 2,5-thiophenedicarboxylic acid, fuma = fumaric acid] have been synthesized and structurally characterized by elemental analysis, single-crystal X-ray diffraction analysis and thermogravimetric analysis. Complex 3 exhibits a 4-connected sqc6 uninodal 3D structure with point symbol of {66}, while the other three complexes all exhibit mutually inclined 2D + 2D → 3D interpenetration structures. The magnetic properties reveal that complex 1, 2, and 4 show the antiferromagnetic exchange interaction behavior. An observed difference in structure and magnetic behavior in complex 3 is driven by coordination types of carboxylate building blocks and the final structure. Magnetic study indicates the magnetic-exchange coupling not only depends on the nature of the metal centers but the structure of the metal–organic framework can affect the magnetic. And then, the UV–Vis DRS properties of four complexes were also investigated. [ABSTRACT FROM AUTHOR]