Hydrothermal Synthesis, Structure and Characterization of a New 2D Co(II) Coordination Polymer Based on Flexible Double Imidazole Derivative and Oxalate

A 1D supramolecular compound [dmbbbi](1) and a 2D cobalt coordination polymer [Co(dmbbbi)(ox)](2)(2) [dmbbbi=1,1-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), ox=oxalate], C48H52Co2N8O8, were obtained under hydrothermal conditions by tuning the molar ratio of the reactants. The crystal structure analysis reveals that in compound 1, the adjacent dmbbbi molecules connect with each other via hydrogen bonds to form a ID supramolecular chain. In compound 2, two crystallographically independent Co2+ ions show the same six-coordination mode. Each Co2+ ion is coordinated by four oxygen atoms from two ox anions and two nitrogen atoms from two cis-dmbbbi ligands. The adjacent Co2+ ions are bridged by ox anions to generate an infinite 1D zigzag chain, which is extended by pairs of dmbbbi ligands to form a 2D honeycomb-like (6,3) network. Moreover, the thermal stability and the electrochemical property of compound 2 were studied.