Reactivity of group 4 benzamidinate complexes towards mono- and bis-substituted silanes and 1,5-hexadiene

Zirconium and titanium bis(benzamidinate) dimethyl complexes were found to be active catalytic precursors for the oligomerization of mono- and bis-substituted silanes. The activation of such complexes, by an excess of MAO or by an equimolar amount of B(C6F5)3, increases the catalytic activity of the complexes and the molecular weight of the obtained oligosilanes. The maximum polymerization index that was accomplished (n = 90) is by far the largest obtained with other organometallic complexes. In addition, the activated benzamidinate catalysts were also found to be active for the polymerization of 1,5-hexadiene producing poly(methyl-1,3-cyclopentane). For the latter, the results obtained with C2-symmetry bis(benzamidinate) dimethyl complexes were compared with a chiral complex bearing a myrtanyl group at the benzamidinate ligand.

Graphical abstractCationic zirconium and titanium bis(benzamidinate) dimethyl complexes are active catalyst for the polymerization of 1,5-hexadiene producing poly(methyl-1,3-cyclopentane) and for the polymerization or the oligomerization of mono- and bis-substituted silanes. For polysilanes, the maximum polymerization index that was accomplished (n = 90) is by far the largest obtained with organometallic complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide