1,3-Diene Polymerization Mediated by Homoleptic Tetramethylaluminates of the Rare-Earth Metals
1,3-Diene Polymerization Mediated by Homoleptic Tetramethylaluminates of the Rare-Earth Metals
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DOI：
10.3390/catal8020061
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发表时间：
2018-02-01
期刊：
影响因子：
3.9
通讯作者：
Anwander, Reiner
中科院分区：
文献类型：
--
作者：
Hollfelder, Christoph O.;Jende, Lars N.;Anwander, Reiner
在过去的二十年中，三价稀土金属的均配四甲基铝酸盐Ln（AlMe 4）（3）已经成为1，3-二烯聚合领域中有效催化剂设计的有用组分。以前的工作主要集中在Ln（AlMe 4）（3）预催化剂（Ln = La、Ce、Pr、Nd、Gd和Y）在Et 2AlCl作为活化剂存在下的异戊二烯聚合。主要研究了使用Ln（AlMe 4）（3）（其中Ln = La、Y和Nd沿着）与硼酸盐/硼烷助催化剂[Ph 3 C][B（C6 F5）（4）]、[PhNMe 2 H][B（C6 F5）（4）]和[B（C6 F5）（3）]的聚合，原因是与辅助配体支撑的体系进行比较（参见半夹心复合物）。本文研究了Ln = La、Ce、Pr、Nd、Gd、Tb、Dy、Ho、Y、Er和Lu共十一种稀土元素。综述了Ln（AlMe 4）（3）在全氟硼酸盐/硼烷助催化剂和R2 AlCl型活化剂（R = Me，Et）存在下的聚合行为，探讨了单体异戊二烯和1，3-丁二烯（以及初步的乙烯）的聚合。对于几种催化剂/助催化剂组合（例如，Gd（AlMe4）（3）/Me2AlCl，>99.9%）。通过筛选预反应时间和助催化剂浓度进行间接观察，可以深入了解活性物质的“黑匣子”。用H-1/C-13 NMR和ATR-IR联用技术研究了聚二烯烃的微观结构。此外，[LuMe 6（Li（thf）（x））（3）]与AlMe 3的反应已被用作高效合成Lu（AlMe 4）（3）的新策略。报道了Gd（AlMe_4）（3）和Tb（AlMe_4）（3）的固态结构。
During the past two decades homoleptic tetramethylaluminates of the trivalent rare-earth metals, Ln(AlMe4)(3), have emerged as useful components for efficient catalyst design in the field of 1,3-diene polymerization. Previous work had focused on isoprene polymerization applying Ln(AlMe4)(3) precatalysts with Ln = La, Ce, Pr, Nd, Gd and Y, in the presence of Et2AlCl as an activator. Polymerizations employing Ln(AlMe4)(3) with Ln = La, Y and Nd along with borate/borane co-catalysts [Ph3C][B(C6F5)(4)], [PhNMe2H][B(C6F5)(4)] and [B(C6F5)(3)] were mainly investigated for reasons of comparison with ancillary ligand-supported systems (cf. half-sandwich complexes). The present study investigates into a total of eleven rare-earth elements, namely Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Er and Lu. A full overview on the polymerization behavior of Ln(AlMe4)(3) in the presence of perfluorinated borate/borane cocatalysts and R2AlCl-type activators (R = Me, Et) is provided, probing the monomers isoprene and 1,3-butadiene (and preliminary ethylene). Virtually complete cis-1,4-selectivities are obtained for several catalyst/cocatalyst combinations (e.g., Gd(AlMe4)(3)/Me2AlCl, >99.9%). Insights into the black box' of active species are obtained by indirect observations via screening of pre-reaction time and cocatalyst concentration. The microstructure of the polydienes is investigated by combined H-1/C-13 NMR and ATR-IR spectroscopies. Furthermore, the reaction of [LuMe6(Li(thf)(x))(3)] with AlMe3 has been applied as a new strategy for the efficient synthesis of Lu(AlMe4)(3). The solid-state structures of Gd(AlMe4)(3) and Tb(AlMe4)(3) are reported.