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Raising the N-aryl fluoride content in unsymmetrical diaryliminoacenaphthylenes as a route to highly active nickel(ii) catalysts in ethylene polymerization.

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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. Sun
Five 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, 2016

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Chemistry

Version

  • AM (Accepted Manuscript)

Published in

Dalton Transactions

Publisher

Royal Society of Chemistry

issn

1477-9226

eissn

1477-9234

Acceptance date

2016-10-19

Available date

2017-10-20

Publisher version

http://pubs.rsc.org/en/Content/ArticleLanding/2016/DT/C6DT03817D

Notes

Electronic Supplementary Information (ESI) available: NMR spectra for the ligands L1 – L5 and complexes Ni1 – Ni10; crystallographic data in CIF format. CCDC 1504611 (Ni2) 1504612 (Ni4). Author confirms PDF is post-print.

Language

en

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