Solution Structure and Reactivity with Metallocenes of AlMe2 F: Mimicking Cation-Anion Interactions in Metallocenium-Methylalumoxane Inner-Sphere Ion Pairs.

The solution structure of AlMe2 F and its reactivity with a prototypical ansa-metallocene have been investigated by advanced NMR techniques, in an attempt to indirectly shed some light on the structure and working principles of methylalumoxane (MAO) mixtures in olefin polymerization. In solution, AlMe2 F gives rise to a complex equilibrium of oligomeric species, including a heterocubane [(Me2 Al)4 F4 ] tetramer, resembling the behavior of MAO. This complex mixture reacts with (ETH)ZrMe2 (ETH=rac-[ethylenebis(4,5,6,7-tetrahydro-1-indenyl)]) to afford [(ETH)ZrMeδ+ (µ-F)(AlMe2 F)n AlMe3δ- ] inner-sphere ion pairs through successive insertions/deinsertions of AlMe2 F units into the Zr⋅⋅⋅(µ-F) bond.

Olefin⁻Styrene Copolymers.

In this review are reported some of the most relevant achievements in the chemistry of the ethylene⁻styrene copolymerization and in the characterization of the copolymer materials. Focus is put on the relationship between the structure of the catalyst and that of the obtained copolymer. On the other hand, the wide variety of copolymer architecture is related to the properties of the material and to the potential utility.