Formation of dinuclear titanium and zirconium complexes by olefin metathesis-catalytic preparation of organometallic catalyst systems

The titanium complex [(C5H4-allyl)TiCl,] (2) undergoes olefin metathesis coupling when treated with 3 mol % of [Cl-2(L-1))(L-2)Ru=CHPh] (L-1 = L-2 = PCy3, 4 a; V= PCY3, L-2 = (H(2)IMes), 4b) to yield the dimetallic complex [Cl3Ti(C5H4)CH2CH=CHCH2-(C5H4)TiCl3] (5). The allyl-substituted titanocene complex [CP(C5H4-allyl)TiCl2] (3) analogously yields the dimetallic system 6 when treated with 4. The ansa-zirconocene complex [Me2Si(C5H4)(C5H3-allyl)ZrCl2] (7) cleanly yields the analogous dimetallic coupling product 8 (> 95 % isomerically pure), when treated with catalytic amounts of 4b in toluene. Complex 8 gives an active homogeneous ethene or propene polymerization catalyst, especially at elevated temperatures, when treated with excess methylalumoxane.