Preprint Article Version 1 This version not peer reviewed

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

Version 1 : Received: 29 September 2017 / Approved: 29 September 2017 / Online: 29 September 2017 (14:50:39 CEST)

A peer-reviewed article of this Preprint also exists.

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. 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.

Journal reference: Polymers 2017, 9, 531
DOI: 10.3390/polym9100531

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) 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 cocatalyst such as borate and AlR3, these complexes 1-3 exhibit high activities up to 6.8 × 104 (g of polymer)/(molLn h) and high cis-1,4-selectivities up to 97%) in the polymerization of isoprene in toluene, yielding the cis-1,4-polyisoprenes with high molecular weights (Mn up to 710000 g/mol) and bimodal molecular weight distributions (Mw/Mn = 2.0-4.5).

Subject Areas

rare earth metal complexes; 1,3-bis(oxazolinymethylidene)isoindoline ligand; polymerization; isoprene; cis-1,4-selectivity

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