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

Presented here are two d10 metal–organic coordination polymers (CPs), [Zn(C4O4)0.5(μ3-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(μ3-OH)]n+} chains to 3D structure linked through C4O42− 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 {43}2{44·610·8}{45·610}2, whereas 2 possess a trinodal (4,5,6)-connected {42·84} {46·66·83} {48·62}2 topology. Furthermore, the fluorescent and thermal stabilities properties of these two compounds were investigated.