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Open AccessArticle

Cis-1,4-Polymerization of Isoprene by 1,3-Bis(oxazolinymethylidene)isoindoline-Ligated Rare-Earth Metal Dialkyl Complexes

Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 10081, China
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Polymers 2017, 9(10), 531; https://doi.org/10.3390/polym9100531
Received: 29 September 2017 / Revised: 17 October 2017 / Accepted: 18 October 2017 / Published: 20 October 2017
(This article belongs to the Special Issue Olefin Polymerization and Polyolefin)
A series of novel chiral nonmetallocene pincer-type rare-earth metal dialkyl complexes bearing the chiral monoanionic tridentate C2-symmetric 1,3-bis(oxazolinymethylidene)isoindoline (BOXMI-H) ligand (BOXMI)Ln(CH2SiMe3)2 1–3 (1: Ln = Sc, yield = 57%; 2: Ln = Lu, yield = 55%; 3: Ln = Y, yield = 62%) have been prepared in moderate yields via the acid-base reaction between the BOXMI ligand and rare-earth metal tri(trimethylsilylmethyl) complexes. The X-ray diffractions show that both of the complexes 1 and 2 contain one BOXMI ligand and two trimethylsilylmethyl ligands, adopting a distorted trigonal bipyramidal configuration. In the presence of a cocatalyst such as borate and AlR3, these complexes 1–3 exhibit high activities of up to 6.8 × 104 (g of polymer)/(molLn h) and high cis-1,4 selectivities of up to 97% in the polymerization of isoprene in toluene, yielding the cis-1,4-polyisoprenes with heavy molecular weights (Mn of up to 710,000 g/mol) and bimodal molecular weight distributions (Mw/Mn = 2.0–4.5). View Full-Text
Keywords: rare-earth metal complexes; 1,3-bis(oxazolinymethylidene)isoindoline ligand; polymerization; isoprene; cis-1,4 selectivity rare-earth metal complexes; 1,3-bis(oxazolinymethylidene)isoindoline ligand; polymerization; isoprene; cis-1,4 selectivity
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Yu, C.; Zhou, D.; Yan, X.; Gao, F.; Zhang, L.; Zhang, S.; Li, X. Cis-1,4-Polymerization of Isoprene by 1,3-Bis(oxazolinymethylidene)isoindoline-Ligated Rare-Earth Metal Dialkyl Complexes. Polymers 2017, 9, 531.

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