Thermally stable and highly active cobalt precatalysts for vinyl-polyethylenes with narrow polydispersities: Integrating fused-ring and imino-carbon protection into ligand design
journal contributionposted on 2017-02-24, 16:50 authored by Fang Huang, Wenjuan Zhang, Yang Sun, Xinquan Hu, Gregory A. Solan, Wen-Hua Sun
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.
This work was supported by National Natural Science Foundation of China (Nos. U1362204, 51473170, 21473160 and 21374123). GAS thanks the Chinese Academy of Sciences for a Visiting Scientist Fellowship.
CitationNew Journal of Chemistry, 2016, 40 (9), pp. 8012-8023
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Chemistry
- AM (Accepted Manuscript)