Four novel porous frameworks constructed by formate ligand

Four novel porous frameworks, [H2N(CH3)2][M(HCO2)3] (M = Ni 1, M = Co 2), and [M(4,4′-bpy)(HCO2)2(H2O)] · 4H2O (bpy = bipyridine, M = Co 3, Ni 4) constructed by formate ligand, were synthesized and their structures were characterized by IR spectrum, chemical analysis and single crystal X-ray diffraction. Complexes 1 and 2 are allomers and crystallize in the trigonal space group R-3c. They exhibit 3-D frameworks with cubic cavities about 4.9 × 4.9 Å and dimethylammonium is included in it. Complexes 3 and 4 are also allomers and crystallize in monoclinic space group Cc. In these two structures, central metal ions are connected by formate ligand and 4,4′-bipyridine to be 3-D networks with channels about 7.0 × 9.2 Å. Free water molecules are included in it. Thermography analyses were tested to reveal the stability of the frameworks. XRPD results confirm that water molecules can be expulsed from the structures without collapse of the frameworks and the two compounds may have potential application in gas storage and adsorption.