While, the lithocene anion (Cp2Li-) can simply be generated by reacting 2 equiv of CpLi with PPh4Cl in THF, the attempted synthesis of the sodocene anion under similar reaction conditions results in the crystallization of [Cp-][PPh4 +]. The structure consists of “naked” Cp anions pinched between metaphenyl hydrogens of the phosphonium cations. An ansa-sodocene anion in which the two Cp rings are bridged by a −C(Me)2−C(Me)2− chain is obtained by reaction of Me4C2(C5H4Na)2 with 1 equiv of PPh4Cl in THF. Its crystal structure shows a disordered ansa-sodocene anion containing a sandwiched sodium cation solvated by a THF molecule. Unbridged Cp2Na- was obtained by pushing the (CpNa + Cp-) ⇄ Cp2Na- equilibrium to the sodocene anion side. Cell dimensions, space group symmetry, and the molecular structure of [Cp2Na-][PPh4 +] are remarkably similar to that of [Cp2Li-][PPh4 +]. The anion can be described as a centrosymmetric (η5,η5)Cp2Na- sandwich (average C−Na = 2.630(3) Å) with approximate D 5 d symmetry.

Bis(2-N,N-dimethylamino-indenyJ) zirconium dichloride, (2-(CH 3)2 N-C 9 H 6)2 ZrC1 2 • and dimethylsilyl-bridged bis(2-N,N-dimethylamino-indenyl) zirconium dichloride. (CH3)2Si(2-(CH3)2N-C9Hs)2ZrCI2' were prepared by reaction of the corresponding ligand lithium salts with ZrCl" in toluene. Diffractometric structure determinations reveal C 2-symmetrlc complex geometries for both complexes. An increased electron density at the Zr center of the dimethylamino-substituted complexes is indicated by reduction potentials which are 0.3-0.4 V morr negative than those of their unsubstituted analogs. When activated with methyl aluminoxane in toluene solution. (CH3)2Si(2-(CH3)2N-C9Hs)2ZrCI2 catalyzes the polymerization of propene to polymers with a microstructure comparable with that of polymers produced with other Mel Si-bridged bis(indenyJ)ZrCl 2 complexes. but with a substantially increased fraction of i-propyl end groups derived from alkyl exchange between Zr-polymer and AI-Me species.

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SUMMARY: In this paper we report on a zirconocene dichloride/methylaluminoxane catalyst system supported on a crosslinked polystyrene in order to provide ethylene polymerization catalysts for gas phase or slurry processes. Our novel approach uses the Diels-Alder reaction of cyclopentadiene functions as the final, crosslinking synthetic step. This provides polymer supported zirconocene catalysts with a homogeneous distribution of active sites. The catalysts were shown to be highly active and to form spherical beads as proven by scanning electron microscopy.

Chiral, biphenyl-bridged metallocene complexes of general type biph(3,4-R2CsH2)2MCI2 (biph = 1,1'-biphenyldiyI) were synthesized and characterized. For the dimethyl-substituted titanocenes and zirconocenes (R CH 3 ; M Ti, Zr). preparations with increafed overall yields and an optical resolution method were developed. The bis(2-tetrahydroindenyI) complexes (R,R = (CH 2)4; M = Ti, Zr) were obtained by an alternative synthetic route and characterized with regard to their crystal structures. Syntheses of the phenyl-substituted derivatives (R C 6 H 5; M Ti, Zr) and of a chiral, methyl-substituted vanadocene complex (R CH 3; M V) are also reported.