Influence of Aromatic Substituents on the Supramolecular Architectures of Monoorganooxotin Drums

The reaction of n-BuSn(O)(OH) with various substituted benzoic acids affords hexameric organostannoxane drums, [n-BuSn(O)OC(O)R]₆, where R = 2,6-(CH₃)₂−C₆H₃ (1), 4-CH₃−C₆H₄ (2), 4-NH₂−C₆H₄ (3) and 2-NH₂−C₆H₄ (4). The central stannoxane motif (Sn₆O₆) is similar in all these compounds and is surrounded by six substituted benzoate groups. All the drums show an extensive supramolecular organization in the solid state. Accordingly, drum 1 forms a one-dimensional supramolecular assembly mediated by noncovalent interactions such as C−H···O and π···π interactions. Similarly, drums 2−4 form interesting three-dimensional supramolecular assemblies mediated by C−H···O, N−H···N, C−H···π, and π···π interactions in the solid state. The role of the peripheral aromatic substituents in determining the final course of the supramolecular assembly is discussed.