Water linked 3D coordination polymers: Syntheses, structures and applications

Three new coordination polymers (CPs) based on Cd and Pb, [Cd(OBA)(mu-H2O)(H2O)](n) 1, [Pb(OBA)(mu-H2O)](n) 2 [where OBA=4,4'-Oxybis(benzoate)] and [Pb(SDBA)(H2O)](n).1/4DMF 3 (SDBA=4,4'-Sulfonyldibenzoate), have been synthesized and characterized. The single crystal structural studies reveal that CPs 1 and 2 have three dimensional structure. A water molecule bridges two metal centres which appears to the responsible for the dimensionality increase from 2D to 3D. Compound 3 has a supramolecular 3D structure involving water molecule and hydrogen bonds. A structural transformation is observed when 3 was heated at 100 degrees C or kept in methanol, forming [Pb(SDBA)](n) 4. Compound 4 is used as supporting matrix for palladium nanoparticles, PdNPs@4. The PdNPs@4 exhibits good catalytic activity toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4 at room temperature. Luminescence studies revealed that all CPs could be an effective sensor for nitroaromatic explosives.