Hydrothermal Synthesis, Crystal Structure and Characterization of New Coordination Polymer [Co_2(pydc)_2(H_2O)_6]_n·2nH_2O

摘要

A coordination polymer of cobalt(II) containing the pyridine-2,5-dicarboxylate (pydc) ligand and having the composition [Co_2(pydc)_2(H_2O)_6]_n·2nH_2O was prepared by the hydrothermal method. The coordination polymer was characterised by FTIR, single crystal XRD, SEM, TGA-DTA, and N_2 Temperature Programmed Desorption, Brunauer, Emmett and Teller surface area. The polymer contains two cobalt(Ⅱ) ions with slightly distorted octahedral geometry. The carboxylate group at the 2-position of pyridine acts as a bridging ligand between two cobalt metal ions and this expansion leads to formation of a 1-D chain-like coordination polymer. The coordination polymer chains are packed together by well-directed hydrogen bonds to generate a three dimensional mesopor-ous network. The N_2 TPD study shows that the polymer is mesoporous in nature and possesses slit-shaped mesopores with average pore size diameter of 17.78 nm. SEM micrographs show well-defined channels in the solid crystals confirming the porosity of polymer. Thermo-gravimetric studies indicate the robust nature of the polymer. The polymer undergoes thermal decomposition in well-defined steps leading to the formation of cobaltous oxide as the end-product.