For weaker ligands, a considerable amount of unexpected [Al(O2CUBE)(OCUBE)2] -and possibly [Al(O2CUBE)2] -sites was also formed through a side-reaction. This is contrary to the conclusions of Styskalik et al. who assigned the singular, observed symmetric Al NMR resonances at ~49 ppm to the Lewis acid species. From experimental and computational results described here, it is now clear that these resonances correspond to the unexpected [AlO 4 ] - species while the species of interest remained invisible in the 1D synthetically undesirable [AlO4] -species is attributed to the nucleophilic attack of the Me3SnOgroups of the spherosilicate building block at the aluminum site due to its Lewis acid properties. . Peak data for the deconvolution of Si MAS NMR spectra of prepared products ......