Hydrolysis vs dismutation in diorganostannate salts – Synthesis and structural studies of (hydrated)diorganotin cations and triorganotin alkanesulfonates

The reactions between diphenyl/di-n-butyltin oxide, dialkyl sulfite, and tetra-n-butylammonium iodide (120 °C, 20 h) proceed via isomerization of the sulfite to sulfonate anion and afford the stannate salts, [n-Bu4N][Ph2Sn(OSO2Et)3] (1) and [n-Bu4N][n-Bu2Sn(OSO2n-Pr)3] (2). The solutions of 1 and 2 in acetonitrile upon exposure to atmospheric conditions resulted in the isolation of multicomponent molecular crystals, [Ph2Sn(H2O)4][n-Bu4N]3[OSO2Et]5·3H2O (3), [n-Bu2Sn(H2O)4][n-Bu4N]2[OSO2n-Pr]4·H2O (4) and [n-Bu2Sn(μ-OH)(H2O)2]2[n-Bu4N]2[OSO2n-Pr]4 (5). In the solid state, the diorganotin cations in 3–5 owe their stability to OH---O hydrogen bonds with non-coordinating sulfonate anions. Reactions of the previously reported stannate salt, [n-Bu4N][Ph2Sn(OSO2Me)3] (6) with N-donor ligands provide a manifestation of phenyl group dismutation to afford new coordination assemblies, [Ph3Sn(OSO2Me)H2O][4,4′-bipy] (7) and [Ph3Sn(OSO2Me)] (8). X-ray crystallographic studies reveal affinity of the alkanesulfonates to function in both primary and secondary coordination sphere that enables the formation of anionic, cationic, and neutral organotin frameworks.