Inorganic crown: the host–guest chemistry of a high nuclearity ‘Celtic-ring’ isopolyoxotungstate [H12W36O120]12−

Abstract

A range of complexes based on the high-nuclearity {W₃₆} isopolyoxotungstate cluster, [H₁₂W₃₆O₁₂₀]¹²⁻, with a triangular topology has been isolated by using the organic cation, protonated triethanolamine. In analogy to an 18-crown-6 crown ether with six oxygen donors on a ring, the cluster can form alkali and alkaline earth metal complexes {M⊂W₃₆} (M = K⁺, Rb⁺, Cs⁺, NH₄⁺, Sr²⁺ and Ba²⁺, 1–6, respectively). Compounds 1–6 were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy. Comparisons between the structures of 1–6 and 18-crown-6 as well as the symmetry directing influence of the organo-cations in the isolation of the overall cluster architecture are discussed.