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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Configurationally flexible zinc complexes as catalysts for rac-lactide polymerisation
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Configurationally flexible zinc complexes as catalysts for rac-lactide polymerisation

机译：将柔性锌配合物作为Rac丙交酯聚合的催化剂

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Zn(N(SiMe3)(2))(2) was reacted with pyridinemethanol and R,R-N,N-di(methylbenzyl)-2,5-diiminopyrrole (L1H) to afford the dimeric complex (L1)(2)Zn-2(-OR)(2). The complex showed moderate activity in rac-lactide polymerization to heterotactic polymer (P-r = 0.75). 2,4-Di-tert-butyl-6-aminomethyl-phenol ligands with amino = N,N,N,N-tetramethyldiethylenetriamine (L2H) or di-(2-picoly)amine (L3H) were reacted with ZnEt2 to form (L2)ZnEt and with Zn(N(SiMe3)(2))(2) to form the respective amide complexes. All complexes, including (L1)(2)Zn-2(-OR)(2) were characterised by X-ray diffraction studies. (L2)ZnEt was unreactive toward ethanol, but the amide complexes afforded (L2)ZnOEt and (L3)ZnOEt upon reaction with ethanol, which were used in rac-lactide polymerization without isolation. All complexes racemise readily at room temperature and show apparent C-s-symmetry in their NMR spectra. The ethoxide complexes were highly active in lactide polymerization, with (L3)ZnOEt reaching full conversion in 15 min at 0.5 mM catalyst concentration at room temperature. In both cases, introduction of a second donor arm on the central nitrogen introduced a slight bias for isotactic monomer enchainment (P-m = 0.55-0.60), which for (L3)ZnOEt was dependent on catalyst concentration.
机译：Zn（N（SIME3）（2））（2）与吡啶甲醇和R，RN，N-DI（甲基苄基）-2,5-二聚氨酸（L1H）反应，得到二聚体复合物（L1）（2）Zn- 2（ - 或）（2）。该复合物在rac丙交酯聚合中显示出与异型聚合物（p-r = 0.75）的中等活性。 2,4-二叔丁基-6-氨基甲基 - 酚配体与氨基= N，N，N，N-四甲基二亚二亚胺（L2H）或二（2-蓄积）胺（L3H）与Znet2反应以形成（ L2）Znet和Zn（N（SIME3）（2））（2）形成相应的酰胺复合物。 X射线衍射研究表征了所有复合物，包括（L1）（2）（2）（2）Zn-2（2）。 （L2）Znet对乙醇不能反应，但酰胺配合物得到（L2）ZnOET和（L3）ZnOET在与乙醇反应时，其用于Rac丙交酯聚合而不分离。所有复合物在室温下易于出发，并在其NMR光谱中显示出明显的C-S对称性。乙氧化物配合物在丙交酯聚合中高度活性，（L3）ZnOet在室温下在0.5mM催化剂浓度下在15分钟内达到全转化。在这两种情况下，在中央氮气上引入第二供体臂引入了用于全同立构单体搭配的轻微偏压（P-M = 0.55-0.60），其用于（L3）ZnOET取决于催化剂浓度。

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