The titanium complex [(C(5)H(4)bond;allyl)TiCl(3)] (2) undergoes olefin metathesis coupling when treated with 3 mol % of [Cl(2)(L(1))(L(2))Ru=CHPh] (L(1)=L(2)=PCy(3), 4 a; L(1)=PCy(3), L(2)=(H(2)IMes), 4 b) to yield the dimetallic complex [Cl(3)Ti(C(5)H(4))-CH(2)CH=CHCH(2)-(C(5)H(4))TiCl(3)] (5). The allyl-substituted titanocene complex [Cp(C(5)H(4)bond;allyl)TiCl(2)] (3) analogously yields the dimetallic system 6 when treated with 4. The ansa-zirconocene complex [Me(2)Si(C(5)H(4))(C(5)H(3)bond;allyl)ZrCl(2)] (7) cleanly yields the analogous dimetallic coupling product 8 (>95 % isomerically pure), when treated with catalytic amounts of 4 b in toluene. Complex 8 gives an active homogeneous ethene or propene polymerization catalyst, especially at elevated temperatures, when treated with excess methylalumoxane.
Bis [(5-hexenyl)cyclopentadienyl]zirconium dichloride (3) underwent ring-closure olefin metathesis with loss of ethylene when treated with 10 mol % of the [Cl 2 (PCy 3 ) 2 Ru=CHPh] catalyst in refluxing dichloromethane, to yield the large ansa-zirconocene complex [dec-5-ene-1,10-diylbis(η 5 -cyclopentadienyl)]ZrCl 2 (trans-4). Characterization by NMR and by X-ray diffraction revealed that the isolated complex contained a trans-C=C double bond inside the ansa bridge. Similarly, bis[(allyl)cyclopentadienyl]ZrCl 2 (7) gave the ansametallocene [but-2-ene-1,4-diylbis(η 5 -cyclopentadienyl)]zirconium dichloride (cis-8) when treated with the same ruthenium metathesis catalysts (10 mol %) under similar conditions, except that a cis-C=C double bond was now found to be present (shown by NMR and X-ray diffraction). The cis-8 complex was used as a homogeneous Ziegler−Natta catalyst
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