文献类型：期刊文献

英文题名：Synthesis of Highly Branched Polyethylene Using "Sandwich" (8-p-Tolyl naphthyl α-diimine)nickel(II) Catalysts

作者：Zhang, Danfeng[1];Nadres, Enrico T.[2];Brookhart, Maurice[3];Daugulis, Olafs[2]

机构：[1]E China Univ Sci & Technol, Shanghai Key Lab Adv Polymer Mat, Sch Mat Sci & Engn, Shanghai 200237, Peoples R China;[2]Univ Houston, Dept Chem, Houston, TX 77204 USA;[3]Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA

年份：2013

卷号：32

期号：18

起止页码：5136

外文期刊名：ORGANOMETALLICS

收录：;EI(收录号：20134016803823);WOS:【SCI-EXPANDED(收录号:WOS:000326261200017)】；

基金：This research was supported by NSF (grant CHE-1010170 to M.B.), the Welch Foundation (Grant No. E-1571 to O.D.), and the Norman Hackerman Advanced Research Program (to O.D.). D.Z. thanks the China Scholarship Council for a Visiting Scholar Research Fellowship. We thank Dr. Peter S. White for help with collecting and solving the X-ray structure of 13 and Mr. (ban Chen for providing GPC analyses.

语种：英文

外文关键词：Chains - Ethylene - Nickel compounds - Polyethylenes

摘要：Nickel(II) alpha-diimine dibromide complexes incorporating 8-p-tolylnaphthylimino groups have been prepared and used for ethylene polymerization by activation with modified methylalumoxane (MMAO). These catalysts possess increased axial bulk relative to standard diimine-nickel complexes, resulting in lower rates of chain transfer relative to chain propagation rates and thus higher polymer molecular weights and narrower PDIs. They yield the most highly branched PE produced by Ni catalysts seen to date. The easy synthesis of 8-aryl-1-naphthylamines provides ready access to a new class of alpha-diimine-based nickel catalysts in which the 8-substituent is ideally positioned to provide steric bulk at the axial sites.