Synthesis, structural characterization, and transmetalation reactions of a tetranuclear magnesium silsesquioxane complex

The reaction of a silsesquioxane trisilanol with methylmagnesium chloride leads to an unprecedented tetranuclear Mg silsesquioxane complex 1 in high yield. The crystal structure shows an unusually short Mg-Cl bond, indicative of an electron-deficient Mg atom. 1 Was used as transmetalation agent for the synthesis of metal silsesquioxane complexes. Transmetalation activity was low, but can easily be followed by multinuclear NMR. Crystal data for 1: C78H142Cl2Mg4O26Si14.6(C4H8O), a 15.744(1), b 26.526(2), c 16.917(1) .ANG., b 113.229(2) Deg, monoclinic, space group P21/n, , Z = 2. [on SciFinder (R)]