Synthesis, structure and characterizations of a novel 3D coordination polymer constructed from rare castellated inorganic chains

Self-assembly of CdCl2 and 1,2,4-triazole under hydrothermal condition yields a novel three-dimensional coordination polymer, namely {[Cd8Cl4(Trz)12(H2O)]·2H2O}n (1) (Trz = 1,2,4-triazole). Single-crystal X-ray diffraction reveals that four of the five independent Cd centers are linked by two μ2-Cl and two μ3-Cl atoms to form novel heptanuclear [Cd7Cl4] clusters, which are connected by the bridging water molecules to generate an unprecedented 1D castellated inorganic chain. Furthermore, the fifth unique Cd center and the castellated Cd–Cl–O chain are joint to each other via six different μ3-Trz ligands to give a 3D organic–inorganic hybrid framework of 1.