rev manuscript_GAS.pdf (1.41 MB)
Raising the N-aryl fluoride content in unsymmetrical diaryliminoacenaphthylenes as a route to highly active nickel(ii) catalysts in ethylene polymerization.
journal contribution
posted on 2016-11-15, 10:35 authored by X. Wang, L. Fan, Y. Yuan, S. Du, Y. Sun, Gregory A. Solan, C. Y. Guo, W. H. SunFive examples of selectively fluorinated unsymmetrical diiminoacenaphthylenes, 1-[2,6-{(4-FC6H4)2CH}2-4-FC6H4N]-2-(ArN) C2C10H6 (Ar = 2,6-Me2C6H3L1, 2,6-Et2C6H3L2, 2,6-iPr2C6H3L3, 2,4,6-Me3C6H2L4, 2,6-Et2-4-MeC6H2L5), have been synthesized and used to prepare their corresponding nickel(ii) halide complexes, LNiBr2 (Ni1-Ni5) and LNiCl2 (Ni6-Ni10). Both (1)H and (19)F NMR spectroscopy techniques have been employed to characterize paramagnetic Ni1-Ni10; an inequivalent fluorine environment is a feature of the tetrahedral complexes in solution. Upon activation with relatively low ratios (ca. 600 equiv.) of ethylaluminum sesquichloride (Et3Al2Cl2, EASC), all the nickel complexes displayed high activities toward ethylene polymerization at 30 °C with precatalyst Ni4 the standout performer at 2.20 × 10(7) g of PE per mol of Ni per h, producing highly branched polyethylenes. In comparison with related diiminoacenaphthylene-nickel catalysts, these current systems, incorporating a high fluorine content on one N-aryl group, display superior productivity. In addition, the molecular structures of Ni2 and Ni4 are reported and the active catalyst is probed using (19)F NMR spectroscopy.
Funding
This work is supported by the National Natural Science Foundation of China (Nos. U1362204, 21374123 and 51373176). GAS thanks the Chinese Academy of Sciences for a Visiting Scientist Fellowship.
History
Citation
Dalton Transactions, 2016Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of ChemistryVersion
- AM (Accepted Manuscript)