Synthesis, characterization and crystal structure of a Er-III mono-substituted [alpha-SiW11O39](8-) polyoxotungstate containing one-dimensional zigzag chainlike structure

摘要

A Keggin-type monovacant silicotungstate derivative K2H2{Er(H2O)(6)[Er(H2O)(3)SiW11O39]}(2)(.)22H(2)O (1) has been synthesized by reaction of the polyoxometalate alpha-K(8)SiW(11)O(39)(.)13H(2)O ligands with erbium(III) cations in the aqueous solution under moderate condition, and characterized by elemental analyses, IR, UV-visible spectroscopy and X-ray single-crystal diffraction. Crystal data: K2H2{Er(H2O)(6)[Er(H2O)(3)SiW11O39]}(2)(.)22H(2)O, triclinic, P - 1, a = 12.463(3), b = 14.849(3), c = 16.772(3) Angstrom, alpha = 95.37(3), beta = 94.65(3), gamma = 106.76degrees, Z = 1, R-1 = 0.0638, wR(2) = 0.1140. X-ray single-crystal diffraction reveals that the polyanion of crystalline 1 is made up of two crystallographically identical polyoxometalate-based {Er(H2O)(6)[Er(H2O)(3)SiW11O39]}(2-) building block units, which are linked through erbium centers by means of the terminal oxygen atoms from the backbone of precursor [alpha-SiW11O39]8(-), generating a novel 1D chain-like structure. Variable-temperature magnetic susceptibility study indicates the presence of the relatively strong spin-orbital coupling in compound I in the wide temperature region of 70-300 K. (C) 2004 Elsevier B.V. All rights reserved.