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

Four CdII-(e,a-cis-1,2-chdc) complexes, [Cd(H2O)(1,2-chdc)(2,2′-bpy)] 1, [Cd(1,2-chdc)(bpe)]n2, [Cd2(1,2-chdc)(4,4′-bpy)2]n3A, 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 CdII-(e,a-cis-1,2-chdc) complexes have been varied. Two carboxylates in e,a-cis-1,2-chdc coordinate to CdII 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.

► Four new structures of CdII complexes containing 1,2-chdc have been determined.
► Depending on ligands, the structures of CdII-(1,2-chdc) complexes have been varied.
► Two carboxylates in 1,2-chdc coordinate to CdII ions in chelating, bridging, and chelating/bridging modes.