Effect of central metals and N-donor ligands on the architectures of a series of coordination polymers based on a bis(sulfanediyl) thiadiazole diacetate

Five new transition metal coordination polymers, namely, [Co(bbbm)(BSTDA)] (1), [Co(bdmbmb)(BSTDA)(H2O)]·(H2O) (2), [Ni(bbbm)(BSTDA)(H2O)2] (3), [Ni2(3-dpyh)2(BSTDA)2(H2O)] (4) and [Cd(bbbm)1.5(BSTDA)] (5) have been synthesized from an S-/thiadiazole-containing dicarboxylate [H2BSTDA = bis(sulfanediyl) thiadiazole diacetic acid] and different flexible/semi-rigid N-donor ligands [bbbm = 1,1-(1,4-butanediyl) bis-1H-benzimidazole, bdmbmb = 1,4-bis(5,6-dimethylbenzimidazole-1-yl)benzene and 3-dpyh = N,N′-bis(3-pyridinecarboxamide)-1,6-hexane]. Structural analysis indicates that the title complexes present different structures although using the same S-/thiadiazole-containing dicarboxylate. Complex 1 is a 3D framework constructed from 2D (63) Co-BSTDA layers and 1D Co-bbbm chains. When the flexible bbbm in 1 was replaced by a semi-rigid bdmbmb ligand, a 2D parallelogram (4,4) network 2 derived from 1D Co-BSTDA and Co-bdmbmb single chains has been obtained. Complex 3, with NiII ion as substitute of CoII ion in 1, exhibited a 2D (4,4) network constructed form 1D Ni-BSTDA and Ni-bbbm single chains. When the bbbm in 3 was replaced by a longer and more flexible N-donor ligand 3-dpyh in 4, a 2D wave-like (4,4) layer constructed from [Ni-BSTDA]2 and [Ni-(3-dpyh)]2 double chains with bimetallic nodes was generated. While the CoII ion in 1 was substituted by CdII ion in 5, a 3D framework crossed by 2D (63) wave-like Cd-bbbm layers and 1D zigzag Cd-BSTDA chains was obtained. Structural diversity in complexes 1–5 demonstrates that the coordination characters of metal ions, the spacer length and flexibility of N-donor ligands have great influence on the final structures of the title complexes. In addition, fluorescence properties of complexes 1–5 are also reported in this paper.

Five coordination polymers based on a S-containing dicarboxylate and different N-donor ligands have been hydrothermally synthesized. The central metals and N-donor ligands have great influence on the final structures of title complexes.Figure optionsDownload as PowerPoint slide