Cu(II) Coordination Polymers Containing Mixed Ligands with Different Flexibilities: Structural Diversity and Iodine Adsorption.

Reactions of N,N '- bis (3-methylpyridyl)oxalamide ( L 1 ), N , N '- bis (3-methylpyridyl)adipoamide ( L 2 ) and N , N '- bis (3-methylpyridyl)sebacoamide ( L 3 ) with tricarboxylic acids and Cu(II) salts afforded {[Cu( L 1 )(1,3,5-HBTC)]·H 2 O} n (1,3,5-H 3 BTC = 1,3,5-benzenetricarboxylic acid), 1 , {[Cu 1.5 ( L 2 ) 1.5 (1,3,5-BTC)(H 2 O) 2 ]·6.5H 2 O} n , 2 , [Cu( L 2 ) 0.5 (1,3,5-HBTB)] n (1,3,5-H 3 BTB = 1,3,5-tri(4-carboxyphenyl)benzene), 3 , [Cu 4 ( L 3 )(OH) 2 (1,3,5-BTC) 2 ] n , 4 , {[Cu 3 ( L 3 ) 2 (1,3,5-BTB) 2 ]·2.5MeOH·2H 2 O} n , 5 , and {[Cu 3 ( L 3 ) 2 (1,3,5-BTB) 2 ]·DMF·2H 2 O} n , 6 , which have been structurally characterized by using single crystal X-ray crystallography. Complexes 1-4 form a 2D layer with the {4 4 .6 2 }- sql topology, a 2D layer with the (4.6 2 ) 2 (4 2 .6 2 .8 2 )- bex topology, a three-fold interpenetrated 3D net with the (4 12 ·6 3 )- pcu topology and a 3D framework with the (4 10 ·6 32 ·8 3 )(4 2 ·6) 2 (4 3 ·6 3 ) topology, respectively, whereas 5 and 6 are 3D frameworks with the (6 3 ) 2 (6 4 ·8 2 )(6 8 ·8 5 ·10 2 ) topology. Complex 5 shows a better iodine adsorption factor of 290.0 mg g -1 at 60 °C for 360 min than the other ones, revealing that the flexibility of the spacer ligand governs the structural diversity and the adsorption capacity.