Hydrothermal Synthesis of Two Cationic Bismuthate Clusters: An Alkylenedisulfonate Bridged Hexamer, [Bi₆O₄(OH)₄(H₂O)₂][(CH₂)₂(SO₃)₂]₃ and a Rare Nonamer Templated by Triflate, [Bi₉O₈(OH)₆][CF₃SO₃]₅

This paper reports the synthesis, characterization, and application of two cationic bismuthate clusters by anion templating. The compounds were synthesized under mild hydrothermal treatment and characterized by powder and single-crystal X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. The first material consists of a cationic hexanuclear bismuthate cluster octahedral in geometry and linked by 1,2-ethanedisulfonate molecules. This structure is thermally stable to about 235 °C. In the second compound, discrete cationic nonanuclear bismuthate clusters interact electrostatically with trifluoromethanesulfonate anions to pack into a nearly layered assembly. The material undergoes a transformation to Bi₂O₃ upon loss of the triflate groups at about 385 °C. Both materials demonstrate the use of sulfonate groups for the anion-directed assembly of these rare cationic inorganic structures. The application of the 3D octahedral bismuth cluster material toward acidic heterogeneous catalysis is also reported.