Coordination Polymers Assembled From 3,3',5,5 Acid and Different Bis(Imidazole) Ligands with Varying Flexibility

Abstract

Five new mixed-ligand coordination polymers, formulated as {[Cd<inf>2</inf>(μ<inf>6</inf>-ao<inf>2</inf>btc)(μ-1,4-bmeib)(H<inf>2</inf>O)<inf>2</inf>]·2H<inf>2</inf>O}<inf>n</inf> (1), [Mn<inf>2</inf>(μ<inf>6</inf>-ao<inf>2</inf>btc)(μ-obix)<inf>2</inf>]<inf>n</inf> (2), [Cd<inf>2</inf>(μ<inf>6</inf>-ao<inf>2</inf>btc)(μ-obix)<inf>2</inf>]<inf>n</inf> (3), [Zn<inf>2</inf>(μ<inf>4</inf>-aobtc)(μ-dib)<inf>2</inf>]<inf>n</inf> (4), and {[Zn<inf>2</inf>(μ<inf>4</inf>-ao<inf>2</inf>btc)(μ-dmib)<inf>2</inf>]·2H<inf>2</inf>O}<inf>n</inf> (5) (aobtc and ao<inf>2</inf>btc = mono- and dioxygenated forms of 3,3',5,5'-azobenzenetetracarboxylate, 1,4-bmeib = 1,4-bis(2-methylimidazol-1yl)butane, obix = 1,2-bis(imidazol-1ylmethyl)benzene, dib = 1,4-bis(imidazol-1yl)benzene, and dmib = 1,4-bis(imidazol-1yl)-2,5-dimethylbenzene) have been synthesized using different bis(imidazole) ligands and characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, powder X-ray diffraction, and thermal analyses (TG/DTA). Complexes 1-5 displayed diverse structures depending on flexible, semiflexible, and rigid bis(imidazole) linkers. Complex 1 has a three-dimensional (3D) structure with the rare sqc27 topology. Complexes 2 and 3 are isostructural with 3,6L19 topology. Complexes 4 and 5 display 2-fold interpenetrated 3D structures with new topology (the point symbol of 62·84) and bbf topology (the point symbol of {64.82}{66}<inf>2</inf>), respectively. Ao<inf>2</inf>btc and aobtc ligands show new coordination modes in 1 and 4, respectively. Moreover, thermal and photoluminescence properties of the complexes were discussed in detail. © 2015 American Chemical Society.