Reaction of Butyltin Hydroxide Oxide with <i>p</i>-Toluenesulfonic Acid: Synthesis, X-ray Crystal Analysis, and Multinuclear NMR Characterization of {(BuSn)₁₂O₁₄(OH)₆}(4-CH₃C₆H₄SO₃)₂

Abstract

The reaction of butyltin hydroxide oxide, BuSnO(OH), with p-toluenesulfonic acid, 4-CH3C6H4SO3H, yields the butyltin oxo cluster {(BuSn)12(μ3-O)14(μ2-OH)6}2+ mixed with a soluble ill-defined butyltin oxo polymer, the presence of which was established by solid-state and quantitative solution 119Sn NMR. The reaction conditions were varied in order to optimize the yield of oxo cluster, which can be quantitatively isolated by crystallization as {(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2·C4H8O2 (1·diox). The structure of the latter compound was determined by X-ray diffraction. 1·diox and {(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2 (1) were also characterized by solid-state 119Sn MAS NMR and solution 119Sn, 1H, and 13C NMR. In 1·diox, the existence of weak Lewis interactions, taking place in the crystal between five-coordinate tin atoms and dioxane molecules, was evidenced by solid-state 119Sn NMR. 2D 1H−1H NOESY and ROESY experiments, along with ionic conductivity measurements, have proved that the ionic dissociation between {(BuSn)12O14(OH)6}2+ and 4-CH3C6H4SO3- (PTS-) does not take place in dichloromethane, while it does in the more polar and dissociating dimethyl sulfoxide. Using the 1H−119Sn J-HMQC NMR technique, the weak 2J(1H−O−119Sn) coupling constant between the μ2-OH and the six-coordinate tin nuclei was determined and shown to depend on the solvent.