Assemblies and Properties of Cobalt(I™I™) Coordination Polymers Based on the Substituted Phthalic Acid and N-Donor Co-ligands

Three new mixed ligated cobalt coordination polymers, [Co(3-NPA)(1,2-bimb)](n) (1), [Co(4-NPA)(1,2-bimb)](n) (2) and [Co(4-NPA)(bpe)(H2O)](n) (3) (3-NPAH(2) = 3-nitrophthalic acid, 4-NPAH(2) = 4-nitrophthalic acid, 1,2-bimb = 1,2-bis(imidazol-1-ylmethyl)-benzene, bpe = 1,2-di(4-pyridyl)ethylene) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, and single-crystal and powder X-ray diffractions. Compounds 1 and 2 based on the same auxiliary N-donor ligand show different structures: 1 is a one-dimensional chain structure, while 2 features a two-dimensional layered structure. The structural differences between 1 and 2, which involve the same metal ion and 1,2-bimb ligand, could be attributed to the different coordination modes of 1,2-bimb molecule. In compound 3, a one-dimensional chain structure connected by the carboxylate groups and the Co(I (TM) I (TM)) ions, which are further linked by the bpe molecules to give a two-dimensional layered structure. Thermal stabilities of 1-3 were also investigated. Dominant antiferromagnetic interactions are propagated between the magnetic centers in 3.