Sigurd Becke

Bimetallic Titanocene or Zirconocene/Aluminium Complexes as Active Catalysts in Lactone Polymerization Reactions

The metallocene alkyne complexes [Cp2M(L)(η2-Me3SiC2R)] react with diisobutylaluminium hydride at room temp. by addition of HAl(iBu)2 to yield the heterobimetallic complexes [{Cp2M}(μ-η1:η2-RCCSiMe3)(μ-H){Al(iBu)2}] [{Cp2M}: (η5-C5H5)2Ti, R = Ph 1, R = SiMe32; {Cp2M}: (η5-C5H5)2Zr, R = SiMe33; {Cp2M}: (ebthi)Zr, R = SiMe34] {ebthi: rac-[1,2-ethylene-1,1′-bis(η5-tetrahydroindenyl)]}. Complexes 1−4 were characterized by NMR spectroscopy and 1, 2 and 4 investigated by X-ray crystal structure analysis. Compounds 1−4 were tested as initiators in the ring-opening polymerization of lactones. The results are discussed in comparison to the corresponding monometallic titanocene and zirconocene alkyne complexes.

A Novel Route to Fulvene Complexes of Titanium—Diastereoselective Complexation of Pentafulvenes to Cyclopentadienyltitanium Fragments

An alternative to the known thermally induced syntheses of fulvene complexes of early transition metals is now provided by the direct reductive complexation of pentafulvenes to [CpTiCl] fragments. These generally highly diastereoselective reactions enable a broad variation of substitution patterns and establish an extensive subsequent chemistry.

A 2-indenyl-amido-bridged titanium complex with Cs-symmetry

Abstract A novel Cs-symmetrical constrained titanium(IV) complex [η5:η1-(2-C9H6)SiMe2NtBu]TiCl2 (7) and the preparation thereof is described; the solid-state structure and the use of 7 as a single site catalyst in the (co)polymerisation of ethene and propene is reported.