Two New Zn(II)/Cd(II) Coordination Polymers Based on Rigid Squaric Acid: Crystal Structure, Topology and Fluorescent Properties

Presented here are two d(10) metal-organic coordination polymers (CPs), [Zn(C4O4)(0.5)(mu (3)-OH)] (n) (1) and [Cd(C4O4)(0.5)(OX)(0.5)(H2O)] (n) (2) (H2OX = oxalic acid) constructed from squaric acid (H2C4O4) tectons. Single-crystal X-ray diffraction studies indicated that both 1 and 2 show 3D structures. The two 3D CPs are assembled from 1D {[Zn(mu (3)-OH)] (n) (+) } chains to 3D structure linked through C4O4 (2-) ligands for 1 and 2D {[(Cd1)(2)(C4O4)](2+)} layers pillared by OX2- ligands for 2. The structure of compound 1 can be described as a trinodal (3,6,6)-connected net with the point symbol of {4(3)}(2){4(4)center dot 6(10)center dot 8}{4(5)center dot 6(10)}(2), whereas 2 possess a trinodal (4,5,6)-connected {4(2)center dot 8(4)} {4(6)center dot 6(6)center dot 8(3)} {4(8)center dot 6(2)}(2) topology. Furthermore, the fluorescent and thermal stabilities properties of these two compounds were investigated.