Three New Complexes Based on a Flexible Bis(benzimidazole) Ligand and Rigid/Flexible Organic Carboxylates

Three new polymeric frameworks, [Ni(bbbm)(L1)(2)] (n) (1), [Ni(bbbm)(L2)(2)] (n) (2), and {[Co(bbbm)(L3)]center dot H(2)O} (n) (3) (bbbm = 1,4-bis(N-benzimidazolyl) butane, HL1 = 4-bromobenzoic acid, HL2 = 3-methylbenzoic acid, and H(2)L3 = glutaric acid) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 features a one-dimensional (1D) linear chain structure bridged by bbbm ligands, which is further connected into a supramolecular double chain structure through intermolecular pi-pi stacking interactions. Complex 2 contains 1D zigzag chain, which is further arranged into a 2D supramolecular architecture by hydrogen bonding and pi-pi stacking interactions. In the structure of 3, there are infinite 1D zigzag Co(II)-bbbm chains linked together by L3 ligands to generate an undulated 2D (4,4) sheet, which is further connected by intermolecular pi-pi stacking interactions to form a 3D supramolecular network. Furthermore, thermal stability and luminescent property of 1-3 were investigated.