A new Ni(II) coordination polymer formed by bulky bis(imidazole) and 4,4′-oxybis(benzoic acid): Topological and spectral elucidation

A new coordination polymer, [Ni(dia)(oba)(H2O)]·H2On(1), was synthetized under hydrothermal conditions from the N-donor ancillary ligand, 9,10-di(1H-imidazol-1-yl)anthracene) (dia) and the flexible aromatic carboxylate, 4,4′-oxybis(benzoic acid) (oba) as organic linker. The two-dimensional framework of the polymer can be described as a 4-c uninodal net of topological type sql with point symbol 44.62. The structure well exhibits the rich coordination chemistry of dia and oba ligands as connectors; interestingly, two carboxylate groups of the oba ligand show μ1:η2and μ1:η1bridging coordination modes, connecting two Ni(II) ions possessing a six-connected NiN2O4 octahedral environment. EPR spectra for 1 were measured at different temperature and solvent. Variable temperature magnetic susceptibility confirms that a weak antiferromagnetic interaction among the Ni(II) ions exists. Thermal analysis has also been carried out to assess the thermal stability of 1 and its structural variation as a function of the temperature.