Bis(pyridyl) ancillary ligands modulated uninodal 4-, 5- and 6-connected Cd(ii) coordination polymers based on 3,4-thiophenedicarboxylate linker

Abstract

Three new cadmium coordination polymers with formula {[Cd(tdc)(bpe)(H₂O)]·2H₂O}_n (1), [Cd(tdc)(bpp)]_n (2), and [Cd(Htdc)₂(bipy)]_n (3) have been synthesized by hydrothermal reactions of cadmium acetate dihydrate and 3,4-thiophenedicarboxylic acid (H₂tdc) in the presence of the corresponding bis(pyridyl) ancillary ligands, namely, 1,2-bis(4-pyridyl)ethylene (bpe), 1,3-bis(4-pyridyl)propane (bpp), and 4,4′-bipyridine (bipy), respectively. Structural analyses reveal that complex 1 exhibits a scarcely reported 4-connected 3D framework with irl (4²·6³·8) topology, whereas complex 2 features an unprecedented 5-connected 2D framework with (4⁴·5³·6³) topology. Complex 3 displays a homochiral 3D framework, which can be rationalized as a new 6-connected (5¹⁰·6⁴·7) topology. The results indicate that H₂tdc and bis(pyridyl) ancillary ligands are effective building blocks in constructing polymers with diverse architectures. Solid-state properties for these crystalline materials, such as thermal stability, powder X-ray diffraction have been investigated. Moreover, photoluminescence behaviors of complexes 1–2 are also investigated.