Supramolecular assembly of [Co2(2,2′-bpy)6]·(BTCA)·Cl·11H2O: 3D negatively charged cages

Controlling the ratio of 2,2′-bpy to benzene-1,3,5-tricarboxylic acid produces an interesting complex, namely [Co2(2,2′-bpy)6]·(btca)·Cl·11H2O (H3btca = benzene-1,3,5-tricarboxylic acid, 2,2′-bpy = 2,2′-bipyridine). We report the structural evidence in the solid state of discrete (H2O)11 conformation. This unit is found to act as supramolecular glue in the aggregation of cobalt (II) complex to give a three-dimensional cage-like network through hydrogen-bonding. It is interesting that the structure contains 3D negatively charged cage. The preliminary investigation on the fluorescence property of the complex is presented.