Novel Cd^II coordination polymers (1-D, 2-D to 3-D) constructed from 1,2-cyclohexanedicarboxylate and various bipyridyl ligands

Four Cd^II-(e,a-cis-1,2-chdc) complexes, [Cd(H ₂O)(1,2-chdc)(2,2′-bpy)] 1, [Cd(1,2-chdc)(bpe)]_n 2, [Cd₂(1,2-chdc)(4,4′-bpy)₂]_n 3A, and [Cd(H₂O)(1,2-chdc)(4,4′-bpy)₂]_n· 3n(H₂O) 3B (1,2-chdc = 1,2-cyclohexanedicarboxylate), with different assistant ligands (2,2′-bipyridine (2,2′-bpy), 1,2-bis(4-pyridyl) ethene (bpe), and 4,4′-bipyridine (4,4′-bpy)) have been synthesized and their structures were determined. Depending on the assistant ligands, the structures and dimensionalities of Cd^II-(e,a-cis-1,2-chdc) complexes have been varied. Two carboxylates in e,a-cis-1,2-chdc coordinate to Cd ^II ions in chelating (η¹:η¹), bridging (η¹:η¹:μ₂), and chelating/bridging (η²:η¹:μ₂) modes. Photoluminescence study of the compounds 1 and 2 showed that emission spectrum of compound 1 was observed at 348 nm, while relatively weak luminescence was displayed at 516 nm for 2. The thermal stabilities of these complexes were also examined.