Synthesis, characterization and crystal structure of a ErIII mono-substituted [a-SiW11O39]82 polyoxotungstate containing one-dimensional zigzag chainlike structure

A Keggin-type monovacant silicotungstate derivative K2H2{Er(H2O)6[Er(H2O)3SiW11O39]}2·22H2O (1) has been synthesized by reaction of the polyoxometalate a-K8SiW11O39·13H2O ligands with erbiumIII 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)3SiW11O39]}2·22H2O, triclinic, P 2 1; a ¼ 12:463ð3Þ; b ¼ 14:849ð3Þ; c ¼ 16:772ð3Þ A ° , a ¼ 95:37ð3Þ; b ¼ 94:65ð3Þ; g ¼ 106:768; Z ¼ 1; R1 ¼ 0:0638; wR2 ¼ 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)3SiW11O39]}22 building block units, which are linked through erbium centers by means of the terminal oxygen atoms from the backbone of precursor [a-SiW11O39]82, generating a novel 1D chain-like structure. Variable-temperature magnetic susceptibility study indicates the presence of the relatively strong spin-orbital coupling in compound 1 in the wide temperature region of 70–300 K. q 2004 Elsevier B.V. All rights reserved