Two supramolecular complexes based on polyoxometalates and Co-EDTA units via covalent connection or non-covalent interaction

摘要

Two new 3D network organic-inorganic hybrid supramolecular complexes {[Na-6(CoEDTA)(2)(H2O)(13)]center dot (H2SiW12O40) center dot xH(2)O}n (1) and [CoH(4)EDTA(H2O)](2)(SiW12O40) center dot 15H(2)O (2) (H(4)EDTA = Ethylenediamine tetraacetic acid) have been successfully synthesized by solution method, and characterized by infrared spectrum (IR), thermogravimetric-differential thermal analysis (TG-DTA), cyclic voltammetry (CV) and single(-) crystal X-ray diffraction (XRD). Both of the complexes are the supramolecules, but with different liking mode, they are two representative models of supramolecule. complex (1) is a 3D infinite network supramolecular coordination polymer with a rare multi-metal sturcture of sodium-cobalt-containing, which is mainly linked through coordinate-covalent bonds. While complex (2) is normal supramolecule, which linked by non-covalent interactions, such as H-bonding interaction, electrostatic interaction and van der waals force. Both of complex (1) and (2) exhibit good catalytic activities for catalytic oxidation of methanol, when the initial concentration of methanol is 3.0 g m(-3), flow rate is 10 mL min(-1), and the quality of catalyst is 0.2 g, for complex (1) and complex (2) the maximum elimination rates of methanol are 85% (150 degrees C) and 92% (120 degrees C), respectively. (C) 2016 Elsevier Inc. All rights reserved.