Novel two-dimensional Co(II) and Cd(II) coordination polymers with intriguing net topologies

•Three new Co(II) and Cd(II) complexes based on 2,6-bis(imidazole-1-yl)pyridine and terephthalic acid were prepared.•The single X-ray crystallographic studies reveal interesting two-dimensional coordination networks.•Complexes 1 and 2 exhibited the first example of a 2D 4-connected net of 66 topology.•Complex 3 shows a rare 4,5-connected net of 4,5 L20 topology.

Three new two-dimensional coordination polymers were constructed from 2,6-bis(imidazole-1-yl)pyridine (2.6-bip), terephthalic acid (1,4-bdcH2), and M(NO3)∙nH2O (M = Co, Cd). [M(2,6-bip)(1,4-bdc)] (1: M = Co; 2: M = Cd) were prepared under hydrothermal condition, whereas [Cd(2,6-bip)(1,4-bdc)∙xDMF] (3) was obtained under solvothermal condition in DMF solvent. Single-crystal X-ray analyses revealed the first example of a 2D 4-connected net of 66 topology in 1 and 2 and a rare 2D 4,5-connected net of 4,5 L20 topology in 3. All these complexes were thermally robust and emissive in solid-states. This work confirmed the versatility of using hingelike 2,6-bip as a linker and the importance of solvent effect in the process of framework formation.

Graphical abstractThree new two-dimensional coordination polymers are presented. [M(2,6-bip)(1,4-bdc)] (1: M = Co; 2: M = Cd; 2,6-bip = 2,6-bis(imidazole-1-yl)pyridine; 1,4-bdc = 1,4-benzenedicarboxylate) exhibit the first example of a 2D 4-connected net of 66 topology. The framework in [Cd(2,6-bip)(1,4-bdc)∙xDMF] (3) is a rare 4,5-connected net of 4,5 L20 topology.Figure optionsDownload full-size imageDownload as PowerPoint slide