Synthesis,structure, and properties of a new 3D hydrogen-bonded porous coordination polymer

A new coordination polymer, [Cd(HMal)(Bipy)(H₂O) · 2H₂O (I) (H₃Mal is malic acid, Bipy is 4,4′-bipyridine), has been synthesized from H₃Mal and Bipy under hydrothermal conditions and characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction. The X-ray diffraction analysis reveals that I (C₁₄H₁₆N₂O₇Cd) crystallizes in the orthorhombic system, space group Ibam. The adjacent cadmium(II) atoms were first interconnected by the HMal ligands via carboxylate oxygen atoms and its adjacent hydroxyl group to generate an infinite zigzag [Cd(HMal)] _n chain, which are further linked by Bipy ligands to form a 2D wavelike layer. Interestingly, the adjacent layers are further connected via hydrogen bonds, giving rise to a 3D porous framework with a cross-sectional area of 11.690 × 9.326 Ų. The unit cell parameters for I: a = 8,457(1), b = 22.030(7), c = 23.066(7) V = 4297(2) ų, Z = 4.