This work aimed to clarify the involvement of a cationic scandium anisyl species in the scandium-catalyzed chain-transfer polymerization of styrene using anisole as a chain-transfer agent (CTA) as well as its behavior in the presence of N,N-dimethyl-o-toluidine. The reaction of anisole with the catalyst precursor [(C₅Me₄SiMe₃)Sc(CH₂C₆H₄NMe₂-o)][B(C₆F₅)₄] (2) generated by the reaction of (C₅Me₄SiMe₃)Sc(CH₂C₆H₄NMe₂-o)₂ (1) with [Ph₃C][B(C₆F₅)₄] gave the structurally characterizable anisole-coordinated ion-pair complex [(C₅Me₄SiMe₃)Sc(CH₂C₆H₄NMe₂-o)(C₆H₅OMe)][B(C₆F₅)₄] (3). The aminobenzyl unit in 3 remained intact even in the presence of an excess amount of anisole. The formation of an anisyl species from 3 was not observed by ¹H NMR. However, the polymerization of styrene by 3 at either room temperature or 70 °C yielded the anisyl-end-functionalized syndiotactic polystyrene (sPS) as a major product in addition to the dimethylaminobenzyl-end-capped sPS. These results suggest that an equilibrium between the aminobenzyl species 3 and a scandium anisyl species should exist, although the latter was not detected by ¹H NMR. The reaction of the half-sandwich scandium bis(anisyl) complex (C₅Me₄SiMe₃)Sc(C₆H₄OMe-o)₂ (4) with 1 equiv of [Ph₃C][B(C₆F₅)₄] in THF afforded the THF-coordinated cationic scandium monoanisyl complex [(C₅Me₄SiMe₃)Sc(C₆H₄OMe-o)(thf)₂][B(C₆F₅)₄] (5), which upon reaction with HMPA gave the structurally characterizable HMPA-coordinated analogue [(C₅Me₄SiMe₃)Sc(C₆H₄OMe-o)(hmpa)₂][B(C₆F₅)₄] (6). The 4/[Ph₃C][B(C₆F₅)₄] combination in toluene showed high activity for styrene polymerization, selectively yielding the anisyl-end-functionalized sPS. In addition to anisole, N,N-dimethyl-o-toluidine was also found to serve as an efficient CTA for the polymerization of styrene by 1/[Ph₃C][B(C₆F₅)₄], which selectively afforded the aminobenzyl-functionalized sPS.

中文翻译：

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苯甲醚和N，N-二甲基-邻甲苯胺为链转移剂的苯乙烯聚合中的阳离子Scan茴香基物种

这项工作旨在阐明阳离子scan茴香基物种在使用苯甲醚作为链转移剂（CTA）的苯乙烯的of催化链转移聚合中的参与及其在N，N-二甲基-邻甲苯胺。苯甲醚与催化剂前体反应〔（C ₅我₄森达₃）钪（CH ₂ ç ₆ ħ ₄ NME ₂ - ö）] [B（C ₆ ˚F ₅）₄ ]（2）由反应生成的（ C ₅ Me ₄ SiMe₃）Sc（CH ₂ C ₆ H ₄ NMe ₂ - o）₂（1）与[Ph ₃ C] [B（C ₆ F ₅）₄ ]给出结构可表征的苯甲醚配位离子对络合物[（C ₅ Me ₄ SiMe ₃）Sc（CH ₂ C ₆ H ₄ NMe ₂ - o）（C ₆ H ₅ OMe）] [B（C ₆ F ₅）₄ ]（3）。即使在过量的茴香醚存在下，3中的氨基苄基单元仍保持完整。通过¹ H NMR未观察到由3形成茴香基物质。然而，在室温或70°C下，苯乙烯在3的温度下聚合，除了以二甲基氨基苄基封端的sPS外，还产生了以茴香基端官能化的间规聚苯乙烯（sPS）为主要产物。这些结果表明，尽管没有通过¹ H NMR检测到后者，但是应该在氨基苄基物种3和a茴香基物种之间存在平衡。半三明治scan双（茴香基）络合物（C ₅ Me ₄ SiMe₃）具有1当量[ THF ]的[Ph ₃ C] [B（C ₆ F ₅）₄ ]的Sc（C ₆ H ₄ OMe- o）₂（4）提供了THF配位的阳离子scan单茴香基络合物[（C ₅ Me ₄ SiMe ₃）Sc（C ₆ H ₄ OMe- o）（thf）₂ ] [B（C ₆ F ₅）₄ ]（5），与HMPA反应后得到结构上可表征的HMPA配位类似物[[C ₅我₄森达₃）钪（C ₆ H ^ ₄ OMe- ö）（HMPA）₂ ] [B（C ₆ ˚F ₅）₄ ]（6）。甲苯中的4 / [Ph ₃ C] [B（C ₆ F ₅）₄ ]组合物对苯乙烯聚合显示出高活性，有选择地生成经茴香基末端官能化的sPS。除苯甲醚外，还发现N，N-二甲基邻甲苯胺可作为有效的CTA，用于通过1 / [Ph ₃ C] [B（C）聚合苯乙烯。₆ F ₅）₄ ]，其选择性地提供了氨基苄基官能化的sPS。