Polynuclear Bismuth Oxido Sulfonato Clusters, Polymers, and Ion Pairs from Bi₂O₃ under Mild Conditions

Eight novel bismuth(III) sulfonato compounds have been synthesized and characterized using the sonochemical reaction of Bi₂O₃ with a range of sulfonic acids, including 2,5-dimethylbenzenesulfonic acid (2,5-DMSH), 2,4-dinitrobenzenesulfonic acid (2,4-DNSH), 2,5-dichlorobenzenesulfonic acid (2,5-DCSH), 1,2-benzenedisulfonic acid (1,2-BDSH₂), 1,3-benzenedisulfonic acid (1,3-BDSH₂), 2-sulfobenzoic acid (2-SBH₂), 3-sulfobenzoic acid (3-SBH₂), and 2-naphthalenesulfonic acid (NPSH). Six of the complexes (1, 2, 4, and 6-8) were structurally characterized through single-crystal X-ray crystallography. In the presence of the monosulfonic acids 2,5-DMSH, 2,4-DNSH, and 2,5-DCSH, polynuclear bismuth(III) oxido clusters were isolated: namely, [Bi₆O₄(OH)₄(2,5-DMS)₆(H₂O)₆]·10H₂O (1·10H₂O), [Bi₆O₄(OH)₄(2,4-DNS)₆(H₂O)₆]·6H₂O (2·6H₂O), and [Bi₆O₄(OH)₄(2,5-DCS)₆(H₂O)₆] (3). The disulfonic acid 1,3-BDSH₂ also produced an oxido cluster: [Bi₆O₄(OH)₄(1,3-BDS)₃]·8H₂O (5·8H₂O). The remaining diacid ligands (1,2-BDSH₂, 2-SBH₂, and 3-SBH₂), upon reaction with Bi₂O₃, produced polymeric Bi(III) sulfonato complexes: namely [Bi(1,2-BDS)(OH)(H₂O)₂]_∞ (4), [Bi(2-SB)(2-SBH)H₂O]_∞·2H₂O (6·2H₂O), and [NH₂(Me)₂]₂[Bi₂(3-SB)₄]_∞ (7). The larger NPSH ligand produced the monomeric contact ion pair [Bi(NPS)₂(H₂O)₆][NPS]·3H₂O (8·3H₂O), upon sonication with Bi₂O₃.