Syntheses and structures of the first two tetra-scandium substituted polyoxometalates

摘要

The first two tetra-Sc-substituted polyoxotungstates H2K2Na2[Sc-4(H2O)(10)(B-beta-SbW9O33)(2)]center dot 21H(2)O (1) and H20K2Na6[Sc-4(C2O4)(4)(B-beta-SbW9O33)(2)][Sc-4(H2O)(2)(C2O4)(4)(B-beta-SbW9O33)(2)]center dot 64H(2)O (2) have been synthesized and characterized by IR spectroscopy, AC impedance measurements, TG, PXRD, and single-crystal X-ray diffractions. Compound 1 represents an isolated inorganic sandwich-type dimeric POM constructed from two trilacunary Keggin [B-beta-SbW9O33](9-) moieties and four Sc3+ ions, while compound 2 shows an extended organic-inorganic hybrid POM which composes of two kinds of distinct tetra-Sc-substituted polyoxotungstate building units and oxalate ligands. Notably, these two compounds also are the first Sc-containing polyoxotungstates based on trilacunary Keggin [B-beta-SbW9O33](9-) clusters. Electrochemical study showed that compound 2 has good proton conductivity. (C) 2017 Elsevier B.V. All rights reserved.