Organooxotin Cages, {[(<i>n</i>-BuSn)₃(μ₃-O)(OC₆H₄-4-X)₃]₂[HPO₃]₄}, X = H, Cl, Br, and I, in Double O-Capped Structures: Halogen-Bonding-Mediated Supramolecular Formation

The reaction of n-BuSn(O)(OH) with H3PO3 and HOC6H4-4-X (X = H, Cl, Br, and I) afforded the hexanuclear organooxotin cages {[(n-BuSn)3(μ3-O)(OC6H4-4-X)3]2[HPO3]4}, where X = H (1), Cl (2), Br (3), and I (4), in moderate yields. These cages possess double O-capped structures. The oxotin cages 1−4 contain two tritin motifs that are joined by four tripodal [HPO3]2- ligands. The three tin atoms in each tritin subunit are held together by a μ3-capping oxygen atom. In addition three phenolate oxygen atoms act as μ2-bridging ligands between two tin atoms. The molecular structures of 1−4 are intimately related to other organooxotin cages such as the O-capped cluster, the drum, and the football cage. The crystal structures of 2−4 reveal intermolecular halogen-bonding-mediated [X- - -O (X = Cl, Br), I- - -I, and I- - -π] supramolecular assemblies.