Three novel 3D metal-organic frameworks with a 1D ladder, tube or chain as assembly units

Three novel metal-organic frameworks, Cu-4(OH)(2)(SO4)(HBTC)(2)(bpy)center dot bpy (1), Cu-1.5(H2O)(TMBTC)(bpy)center dot 1/2H(2)O (2) and Cd-2(H2O)(5)(TMBTC)(bpy)(2)center dot NO3 center dot 3H(2)O (3), constructed from mixed organic ligands, have been synthesized and characterized. Complex 1 crystallizes in monoclinic space group C2/c and possesses a 3D three-fold interpenetrating framework. The copper ions were first connected by HBTC and SO42- to generate a 1D ladder, which was further linked by a 4,4'-bipyridine ligand to give rise to a 3D interpenetrating framework. Complex 2 crystallizes in monoclinic space group P2/c and possesses a 3D two-fold interpenetrating framework. Similar to 1, the copper ions were first connected by TMBTC to generate a 1D tubular unit, which can be considered as the assembly block. The 1D tubular unit was further linked by 4,4'-bipyridine ligands to result in the formation of the 3D framework. Complex 3 crystallizes in monoclinic space group Cc and has a three-dimensional structure. Different from 1 and 2, the cadmium ions were first connected by a 4,4'-bipyridine ligand to form a 1D chain as the assembly unit, which was further linked by TMBTC ligand to generate the final 3D framework. The photoluminescence measurement of 3 in the solid state at room temperature showed that complex 3 exhibits luminescence, which can be assigned to an intraligand pi -> pi* transition.