Synthesis, Crystal Structure and Theoretical Calculations of Two Zinc, Cobalt Coordination Polymers with 5-Nitroisophthalic Acid and 1,4-Bis(1H-benzimidazolyl)butane Ligands

Two new complexes [Zn(NIPH)(bbib)]2n·nbbib·nH2O (1) and [Co(NIPH)(bbib)]n (2) (H2NIPH = 5-nitroisophthalic acid, bbib = 1,4-bis(1H-benzimidazolyl)butane) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, TG, fluorescence spectroscopy, single-crystal and powder X-ray diffraction. Complex 1 exhibits a two-dimensional network structure and complex 2 shows a three-dimensional framework, which were further extended into three-dimensional supramolecular structure through hydrogen bonds and π–π stacking interactions. Moreover, we analyzed the natural bond orbital using the PBE0/LANL2DZ method in the Gaussian 03 program of complex 1 and 2. The calculation results indicated the obvious covalent interactions between the coordinated atoms and the ZnII, CoII ion respectively.