Huang, Fang Zhang, Wenjuan Sun, Yang Hu, Xinquan Solan, Gregory A. Sun, Wen-Hua Thermally stable and highly active cobalt precatalysts for vinyl-polyethylenes with narrow polydispersities: Integrating fused-ring and imino-carbon protection into ligand design A series of [2-(1-aryliminobenzylidene)-9-arylimino-5,6,7,8-tetrahydrocyclohepta[b]pyridyl]cobalt chlorides (aryl = 2,6-Me2Ph (Co1), 2,6-Et2Ph (Co2), 2,6-i-Pr2Ph (Co3), 2,4,6-Me3Ph (Co4), and 4-Me-2,6-Et2Ph (Co5)), incorporating a fused seven-membered ring and an imino C-phenyl group, was synthesized and characterized. Upon activation with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), Co1-Co5 all showed high activities toward ethylene polymerization with the Co4/MAO system showing the highest activity (8.65 × 106 g(PE) mol-1(Co) h-1). Significantly, these systems exhibited good thermal stability (up to 80 °C) as well as long catalytic lifetimes. The polyethylenes obtained all contained vinyl end-groups as well as narrow polydispersities. These phenyl-modified cobalt precatalysts provide a functional system for generating a unique class of vinyl-polyethylenes due to their ease of preparation, high catalytic activities and thermally stable polymerization. IR content 2017-02-24
    https://figshare.le.ac.uk/articles/journal_contribution/Thermally_stable_and_highly_active_cobalt_precatalysts_for_vinyl-polyethylenes_with_narrow_polydispersities_Integrating_fused-ring_and_imino-carbon_protection_into_ligand_design/10121411