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

Abstract

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.