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首页> 外文期刊>Chemistry: A European journal >Ring-Opening Polymerization of Lactide with Group 3 Metal Complexes Supported by Dianionic Alkoxy-Amino-Bisphenolate Ligands: Combining High Activity,Productivity,and Selectivity
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Ring-Opening Polymerization of Lactide with Group 3 Metal Complexes Supported by Dianionic Alkoxy-Amino-Bisphenolate Ligands: Combining High Activity,Productivity,and Selectivity

机译：丙二酸烷氧基-氨基-双酚盐配体支持的丙交酯与3族金属配合物的开环聚合：兼具高活性，高生产率和高选择性

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A series of new alkoxy-amino-bis(phenols) (H_2L 1-6) has been synthesized by Mannich condensations of substituted phenols,formaldehyde,and amino ethers or diamines.The coordination properties of these dianionic ligands towards yttrium,lanthanum,and neodymium have been studied.The resulting Group 3 metal complexes have been used as initiators for the ring-opening polymerization of rac-lac-tide to provide poly(lactic acid)s (PLAs).The polymerizations are living,as evidenced by the narrow polydispersities of the isolated polymers,together with the linear natures of number average molecular weight versus conversion plots and monomer-to-catalyst ratios.Complex [Y(L6)-(N(SiHMe_2)_2}(THF)] (17) polymerized rac-lactide to heterotactic PLA (P_r = 0.90 at 20 deg C) and meso-lactide to syn-diotactic PLA (P_r = 0.75 at 20 deg C).The in situ formation of [Y(L6)(OiPr)-(THF)] (18) from 17 and 2-propanol resulted in narrower molecular weight distributions (PDI = 1.06).With complex 18,highly heterotactic PLAs with narrow molecular weight distributions were obtained with high activities and productivities at room temperature.The natures of the ligand substituents were shown to have a significant influence on the degree of control of the polymerizations,and in particular on the tacticity of the polymer.
机译：通过取代酚，甲醛，氨基醚或二胺的曼尼希缩合反应，合成了一系列新的烷氧基-氨基-双（酚）（H_2L 1-6）。这些双阴离子配体对钇，镧和钕的配位性能所得的3族金属配合物已被用作外消旋体的开环聚合反应的引发剂，以提供聚乳酸（PLA）。聚合反应是活跃的，窄的多分散性证明了这一点。 [Y（L6）-（N（SiHMe_2）_2}（THF）]（17）聚合的rac--）的合成，以及数均分子量与转化率和单体/催化剂比的线性关系。丙交酯到异规PLA（在20摄氏度时P_r = 0.90），内消旋丙交酯到间规PLA（在20摄氏度时P_r = 0.75）。原位形成[Y（L6）（OiPr）-（THF）] （18）中的17和2-丙醇的分子量分布较窄（PDI = 1.06）。配合物18时，杂多度高在室温下获得了具有高活性和高生产率的具有窄分子量分布的ic PLA。配体取代基的性质显示出对聚合反应的控制程度，特别是对聚合物的立构规整度有重大影响。

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