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Polymers 2017, 9(10), 531; https://doi.org/10.3390/polym9100531

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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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)
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Abstract

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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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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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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