A bimetallic siloxane cage model catalyst. Synthesis, characterization and polymerization behaviour of [(c-C6H11)7(Si7O12)MgTiCl3] n (n= 1,2)

Butylethylmagnesium reacts with polyhedral (c-C6H11)7(Si7O9)(OH)3 to give [(c-C6H11)7(Si7O9)(OH)O2Mg]n(n= 1,2), which upon reaction with TiCl4 gives [(c-C6H11)7(Si7O12)MgTiCl3]n(n= 1,2) as a monomer/dimer mixture; this new bimetallic siloxane cage model catalyst, in the presence of triethylaluminium, shows a high catalytic activity for ethene polymerization.