Catalyst Deactivation Processes during 1‑Hexene Polymerization

The catalyst [Cp₂Zr­(μ-Me)₂AlMe₂]⁺[B­(C₆F₅)₄]⁻ (1) has been studied by electrospray ionization mass spectrometry in order to better understand the complexities of catalyst deactivation in the polymerization of 1-hexene. Using off-line, online, and flow-based methods, we observe that zirconium π-allyl species are unstable in solution and previously unobserved dimethylalane complexes are more stable. The dimethylalane complexes are resistant to further 1-hexene additions, and their formation represents a previously unrecognized pathway for catalyst deactivation.