Hydrothermal Syntheses, Crystal Structures and Luminescence Properties of Zn(II) and Cu(II) Complexes Based on 2,2′-((Sulfonylbis(4,1-phenylene))bis(oxy))diacetic Acid

The 2,2'-((sulfonylbis(4,1-phenylene))bis(oxy))diacetic acid (H2L) and 4,4'-bipyridine (4,4'-bipy) are employed as organic ligands to react with metal salts to obtain two new metal-organic frameworks (MOFs), namely [M2L2(4,4'-biPy)] (M = Zn(1), Cu(2)). They have been successfully synthesized under hydrothermal conditions. Single-crystal X-ray diffraction reveals that two complexes are isostructural and crystallize in orthorhombic system with space group Pbcn. All L2- ligands bridge metal ions to form an infinite 1D Z-shaped chain along the a axis. Then through 4,4'-bipy, contiguous Z-shaped chains are linked to form a 2D layer structure. The luminescent studies of the H2L ligand and complex 1 in the solid state and thermogravimetric analyses (TGA) of two complexes are investigated.