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首页> 外文期刊>Polymers >“Living” Polymerization of Ethylene and 1-Hexene Using Novel Binuclear Pd–Diimine Catalysts
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“Living” Polymerization of Ethylene and 1-Hexene Using Novel Binuclear Pd–Diimine Catalysts

机译：使用新型双核Pd-二胺催化剂“活”聚合乙烯和1-己烯

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We report the synthesis of two novel binuclear Pd–diimine catalysts and their unique behaviors in initiating “living” polymerization of ethylene and 1-hexene. These two binuclear catalysts, [(N^N)Pd(CH 2 ) 3 C(O)O(CH 2 ) m O(O)C(CH 2 ) 3 Pd(N^N)](SbF 6 ) 2 ( 3a : m = 4, 3b : m = 6) (N^N≡ArN=C(Me)–(Me)C=NAr, Ar≡2,6–( i Pr) 2 C 6 H 3 ), were synthesized by simply reacting [(N^N)Pd(CH 3 )(N≡CMe)]SbF 6 ( 1 ) with diacrylates, 1,4-butanediol diacrylate and 1,6-hexanediol diacrylate, respectively. Their unique binuclear structure with two identical Pd–diimine acrylate chelates covalently linked together through an ester linkage was confirmed by NMR and single crystal XRD measurements. Ethylene “living” polymerizations were carried out at 5 °C and under ethylene pressure of 400 and 100 psi, respectively, with the binuclear catalysts, along with a mononuclear chelate catalyst, [(N^N)Pd(CH 2 ) 3 C(O)OMe]SbF 6 ( 2 ), for comparison. All the polyethylenes produced with both binuclear catalysts show bimodal molecular weight distribution with the number-average molecular weight of the higher molecular weight portion being approximately twice that of the lower molecular weight portion. The results demonstrate the presence of monofunctional chain growing species resembling catalyst 2 , in addition to the expected bifunctional species leading to bifunctional “living” polymerization, in the polymerization systems. Both types of chain growing species exhibit “living” characteristics under the studied conditions, leading to the simultaneous linear increase of molecular weight in both portions. However, when applied for the “living” polymerization of 1-hexene, the binuclear catalyst 3a leads to polymers with only monomodal molecular weight distribution, indicating the sole presence of monofunctional chain growing species. These two binuclear catalysts are the first Pd–diimine catalysts capable of initiating bifunctional ethylene “living” polymerization.
机译：我们报告了两种新型双核Pd-二亚胺催化剂的合成及其在引发乙烯和1-己烯的“活性”聚合反应中的独特行为。这两种双核催化剂[[（N ^ N）Pd（CH 2）3 C（O）O（CH 2）m O（O）C（CH 2）3 Pd（N ^ N）]（SbF 6）2（ 3a：m = 4，3b：m = 6）（N ^N≡ArN= C（Me）–（Me）C = NAr，Ar≡2,6–（i Pr）2 C 6 H 3）被合成通过简单地使[（（N ^ N）Pd（CH 3）（N≡CMe）] SbF 6（1）与二丙烯酸酯，1,4-丁二醇二丙烯酸酯和1,6-己二醇二丙烯酸酯反应。 NMR和单晶XRD测量证实了它们独特的双核结构，其中有两个相同的通过酯键共价键合的Pd-二亚胺丙烯酸钯螯合物。使用双核催化剂和单核螯合物催化剂[（N ^ N）Pd（CH 2）3 C（分别在5°C和400和100 psi的乙烯压力下）分别进行乙烯“活”聚合。为了比较，[O] OMe] SbF 6（2）。用两种双核催化剂生产的所有聚乙烯均显示双峰分子量分布，其中较高分子量部分的数均分子量约为较低分子量部分的数均分子量的两倍。结果表明，在聚合体系中，除了导致双功能“活性”聚合的预期双功能物质之外，还存在类似于催化剂2的单官能链增长物质。两种类型的链增长物种在所研究的条件下均表现出“活性”特性，导致两个部分的分子量同时线性增加。然而，当用于1-己烯的“活”聚合时，双核催化剂3a导致仅具有单峰分子量分布的聚合物，表明仅存在单官能链增长物质。这两种双核催化剂是第一种能够引发双官能乙烯“活”聚合的Pd-二亚胺催化剂。

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