A porous framework based on tetrakis(4-pyridyloxymethyl)methane fine-tuned by metal ions: synthesis, crystal structures and adsorption properties

Solvothermal reactions of tetrakis(4-pyridyloxymethyl)methane (TPOM) and 4,4′-oxybisbenzoic acid (H2oba) with different metal ions under different synthesis temperatures produced three new coordination polymers (CPs), namely, {[Co2(TPOM)(oba)2(H2O)2]}n (1), {[Zn2(TPOM)(oba)2]}n (2) and {[Cd2(TPOM)(oba)2(H2O)2]}n (3). 1 and 3 present similar topological structures which can be analyzed in two different ways. 2 exhibits a rare porous structure assembled by the tetra-pyridinate ligand TPOM. The luminescence properties of 2 and 3 as well as those of the corresponding samples immersed in different solvents have been investigated, and they suggested a potential application in luminescence sensing. In addition, the dye and iodine adsorption properties of an activated sample of 2 were also investigated. All of the results indicate that the proper selection of metal ions and auxiliary ligands plays an important role in constructing porous coordination polymers.