Stereoselective Polymerization of Conjugated Dienes

Takeuchi, Daisuke

doi:10.1002/0471440264.pst595

Cited by 15 publications

(17 citation statements)

References 200 publications

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“…Aromatic protons appear in the low-field region (6.72−7.01 ppm). In the 13 Transparent crystals of L 1 H suitable for X-ray analysis were obtained by slow evaporation of a diethyl ether solution at room temperature. The molecular structure of L 1 H is depicted in Figure 1, and crystallographic data and structure refinement data are given in Table 1S in the Supporting Information.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Bis(tetramethylaluminate) Lanthanide Complexes Supported by Bi- and Tridentate Amidinate Ligands: Performance in Isoprene Polymerization

et al. 2021

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The isolable bis(tetramethylaluminate) lanthanide complexes [2-R2,6-XC6H4NC(tBu)(2,6-R1 2C6H3)]Ln(AlMe4)2 (R1 = R2 = X = Me, Ln = La (1); R1 = R2 = X = Me, Ln = Nd (2); R1 = iPr, R2 = H, X = OMe, Ln = La (3); R1 = iPr, R2 = H, X = OMe, Ln = Nd (4)) coordinated by bi- and tridentate amidinate ligands were synthesized by the reactions of the amidines 2,6-Me2C6H3NC(tBu)NH-2,6-Me2C6H3 and 2,6-iPr2C6H3NC(tBu)NH-2-MeOC6H4 with Ln(AlMe4)3 (Ln = La, Nd) and were isolated in 81, 75, 86, and 74% yields, respectively. X-ray analyses revealed that complexes 3 and 4 feature intramolecular coordination of an OMe group to the metal ions. Both AlMe4 fragments in complexes 3 and 4 coordinate to the metal centers in a κ2 mode, while in Nd complex 2 one AlMe4 group adopts a κ2 and the second a κ3-coordination mode. Complexes 1–4 were evaluated as precatalysts for isoprene polymerization. The ternary catalytic systems 1–4/[Ph3C][B(C6F5)4],[PhNHMe2][B(C6F5)4]/nAlR3 (AlR3 = AlMe3, n = 10; AliBu2H, n = 1; AliBu3, n = 10) enable 82–100% conversions of 1000 equiv of monomer at 25 °C within 5–60 min. cis-1,4-Selectivity of the ternary catalytic systems proved to be affected by the type of ligand, the borate, the AlR3 cocatalyst, and the nature of the metallo center and varied in the range of 34.4–91.8%. The binary systems 1–4/[Ph3C][B(C6F5)4],[PhNHMe2][B(C6F5)4] also catalyze isoprene polymerization and afford polyisoprenes containing 96.2–99.0% of cis-1,4 units in polymer chains. The stereoselectivity of binary systems containing complex 1 dramatically depends on the type of borate: 66.8% of trans-1,4 for [Ph3C][B(C6F5)4] and 87.8% of cis-1,4 for [PhNHMe2][B(C6F5)4].

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Section: ■ Results and Discussionmentioning

confidence: 99%

Bis(tetramethylaluminate) Lanthanide Complexes Supported by Bi- and Tridentate Amidinate Ligands: Performance in Isoprene Polymerization

et al. 2021

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“…Conjugated dienes are versatile motifs for constructing molecules that range from natural products to synthetic polymers. , In recent years, hydrofunctionalization has emerged as an attractive and atom-economical method to transform dienes into valuable building blocks . In comparison to other hydrofunctionalizations (e.g., hydroboration or hydroformylation), hydrophosphinylation remains in its infancy (Figure ).…”

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confidence: 99%

Enantioselective Coupling of Dienes and Phosphine Oxides

2018

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“…Many studies have been carried out to obtain poly(1,3-diene)s possessing well-defined microstructure as well as stereoregularity [9,10]. The Ziegler-Natta, metallocene, and nonmetallocene catalysts have been employed as catalysts for the polymerization of conjugated dienes such as 1,3-butadiene and isoprene.…”

Section: Coordination Polymerization Of 13-dienesmentioning

confidence: 99%

Poly(Diene)s: Polybutadiene and Polyisoprene

Tomita¹

2015

Encyclopedia of Polymeric Nanomaterials

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SynonymsDiene polymerization; Polymerization of 1,3-conjugated dienes DefinitionPoly(diene)s are products obtainable by the polymerization of diene monomers carrying two olefin units. In the case of poly(diene)s from conjugated 1,3-diene monomers, in which two olefin units are conjugated to each other, the resulting polymers are often applied to important industrial products such as synthetic elastomers. Poly(1,3-diene)s contain double bonds in the main chain and/or in the pendant group as a result of 1,4-and/or 1,2-polymerizations, respectively. Not only the selectivity of 1,4-and 1,2-polymerizations but also that between cis and trans for the 1,4-polymerizations and the stereoselectivity in the 1,2-polymerization also affect largely the properties of the polymers. Wide varieties of polymerization techniques including the radical, ionic, and coordination polymerizations have been investigated in detail to obtain excellent materials from diene monomers.

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Stereoselective Polymerization of Conjugated Dienes

Cited by 15 publications

References 200 publications

Bis(tetramethylaluminate) Lanthanide Complexes Supported by Bi- and Tridentate Amidinate Ligands: Performance in Isoprene Polymerization

Bis(tetramethylaluminate) Lanthanide Complexes Supported by Bi- and Tridentate Amidinate Ligands: Performance in Isoprene Polymerization

Enantioselective Coupling of Dienes and Phosphine Oxides

Poly(Diene)s: Polybutadiene and Polyisoprene

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