The solution structure of AlMe2F 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, AlMe2F gives rise to a complex equilibrium of oligomeric species, including a heterocubane [(Me2Al)(4)F-4] 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) ZrMed+(m-F)(AlMe2F)(n)AlMe3 delta-] inner-sphere ion pairs through successive insertions/deinsertions of AlMe2F units into the Zr ... (mu-F) bond.
Solution Structure and Reactivity with Metallocenes of AlMe2F: Mimicking CationâAnion Interactions in MetalloceniumâMethylalumoxane Inner-Sphere Ion Pairs
Galdi, Nunzia;Sian, Leonardo;Macchioni, Alceo;Zuccaccia, Cristiano
2017
Abstract
The solution structure of AlMe2F 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, AlMe2F gives rise to a complex equilibrium of oligomeric species, including a heterocubane [(Me2Al)(4)F-4] 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) ZrMed+(m-F)(AlMe2F)(n)AlMe3 delta-] inner-sphere ion pairs through successive insertions/deinsertions of AlMe2F units into the Zr ... (mu-F) bond.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
