Synthesis, structure, and luminescent property of a cobalt (II) compound with a 1D Double-zigzag chain structure using rigid aromatic dicarboxylate acids and flexible bis(2-benzimidazolyl)alkanes linkers

By using the bis (2-benzimidazolyl)alkanes as the N-donor ligand and 1,4-benzenedicarboxylic acid as the second metal linker, a novel cobalt(II) compound with a 1D double-zigzag chain structure, namely, [Co(BDC) (H₂C₃PIm)(H₂O)]_n (1) (H₂C₃PIm=2,2-(1,3-propanediyl)-bis(1H-benzimidazole), BDC = 1,4-benzenedicarboxylic acid) has been synthesized under hydrothermal conditions and characterized by elemental analysis, thermal analysis, X-ray single-crystal diffraction. The crystal belongs to the orthorhombic system, space group Pca21 with a=1.488 6(5) nm, b=1.791 7(5) nm, c=1.894 3(5) nm, V=5.052(3) nm³, D_c=1.360 g•cm^-3, Z=8, F(000)=2 136, Goof=0.986, R₁= 0.042 5, wR₂=0.068 7. In compound 1, the distorted tetrahedral Co(II) ion is bridged by the carboxylic oxygen atoms of the BDC ligand and chelated by the nitrogen atoms of the H₂C₃PIm ligand. Owning to the different of the distorted angles from the BDC ligand, the compound units are linked into 1D double-zigzag chain structure (mode A; mode B) via the C-H⋯π interactions and N-H⋯O, O-H⋯ O hydrogen bonding between uncoordinated carboxylate and the nitrogen atoms of H₂C₂EIm as well as the free water molecules and further extended into a 3D supramolecular structure through the intermolecular hydrogen bonds between the adjacent A and the adjacent B zigzag chains. The luminescent property of compound 1 has also been studied. CCDC: 839239.