Effects of meta-substitution on aggregation in the cubanes [SnNR]₄{R = [2-Me-5-MeOC₆H₃], [2,5-(MeO)₂C₆H₃] and [3,5-(MeO)₂C₆H₃]}

An investigation of the solid-state X-ray structures of the cubanes [SnN{2-Me-5-MeOC₆H₃}]₄, (1), [SnN{2,5-(MeO)₂C₆H₃}]₄, (2), and [SnN{3,5-(MeO)₂C₆H₃}]₄, (3), containing meta-MeO substituents on their aromatic groups, shows that unprecedented modes of intra- and intermolecular association occur. In 1, novel co-ordination of two of the cubane Sn₂N₂ faces by thf ligands is found, the first observation of Lewis base solvation by a separate donor ligand in this class of complexes. In 2, dimerisation of cubane units occurs via a combination of Sn⋯Sn, Sn⋯O and arene⋯Sn interactions, whereas in 3, an unusual ‘sinusoidal’ pattern of aggregation is seen.