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首页> 外文期刊>Chemistry: A European journal >Group 4 dimethylsilylenebisamido complexes bearing the 6-[2-(diethylboryl) phenyl]pyrid-2-yl motif: Synthesis and use in tandem ring-opening metathesis/vinyl-insertion copolymerization of cyclic olefins with ethylene
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Group 4 dimethylsilylenebisamido complexes bearing the 6-[2-(diethylboryl) phenyl]pyrid-2-yl motif: Synthesis and use in tandem ring-opening metathesis/vinyl-insertion copolymerization of cyclic olefins with ethylene

机译：带有6- [2-（二乙基硼基）苯基]吡啶-2-基基序的第4组二甲基甲硅烷基双酰胺基配合物：环烯烃与乙烯的串联开环复分解/乙烯基插入共聚反应的合成及使用

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Two novel Zr~(IV)- and Hf~(IV)-based bisamido complexes bearing the 6-[2-(diethylboryl)phenyl]pyrid-2-yl motif, that is, [ZrCl _2{Me_2Si(DbppN)_2}(thf)] (9) and [HfCl _2{Me_2Si(DbppN)_2}(thf)_2] (10) (DbppN=6-[2-(diethylboryl)phenyl]pyridine-2-amido) have been prepared. Their reactivities have been compared with that of a model precatalyst that does not bear the aminoborane motif. Upon activation with methylalumoxane, precatalysts 9 and 10 are active in the homopolymerization of ethylene (E) yielding high-density polyethylene (HDPE). In the copolymerization of E with cyclopentene (CPE), for example by the action of 9, the presence of CPE resulted in a dramatic increase in the polymerization activity of E, while CPE incorporation remained close to or at zero. In the vinyl-insertion copolymerization of norborn-2-ene (NBE) with E by the action of 9, statistical cyclic olefin copolymers of these two monomers were obtained. At higher NBE concentrations, however, 9 gave rise to reversible ring-opening metathesis (ROMP)/vinyl- insertion polymerization (VIP) of NBE with E, resulting in the formation of multi-block copolymers of the general formula poly(NBE)_(ROMP)-co- poly(NBE)_(VIP)-co-poly(E). This particular feature of precatalyst 9, that is, the ability to induce a reversible α-H elimination/α-H addition reaction, is attributed to the unique role of the 6-[2-(diethylboryl) phenyl]pyrid-2-yl ligand. Accordingly, a model precatalyst lacking this ligand does not have the ability to induce α-H elimination/α-H addition reactions. The different ~(11)B NMR shifts of various diethylborylphenylpyrid-2-ylamines and -amides permit a ranking of the strengths of the B-N bonds in these compounds. This strength of the B-N bond is correlated with the propensity of 9/MAO to produce poly(NBE)_(ROMP)-co- poly(NBE)_(VIP)-co-poly(E) at different temperatures.
机译：带有6- [2-（二乙基硼基苯基）苯基]吡啶-2-基基序的两个新型Zr〜（IV）-和Hf〜（IV）基双酰胺基配合物，即[ZrCl _2 {Me_2Si（DbppN）_2} （thf）]（9）和[HfCl _2 {Me_2Si（DbppN）_2}（thf）_2]（10）（DbppN = 6- [2-（二乙基硼基）苯基]吡啶-2-氨基）已制备。已经将它们的反应性与不带有氨基硼烷基序的模型预催化剂进行了比较。在用甲基铝氧烷活化后，预催化剂9和10在乙烯（E）的均聚中具有活性，从而产生高密度聚乙烯（HDPE）。在E与环戊烯（CPE）的共聚中，例如通过9的作用，CPE的存在导致E的聚合活性急剧增加，而CPE的掺入保持接近或为零。在降冰片烯2-烯（NBE）与E的乙烯基插入共聚中，通过9的作用，获得了这两种单体的统计环烯烃共聚物。然而，在较高的NBE浓度下，9导致NBE与E的可逆开环复分解（ROMP）/乙烯基插入聚合（VIP），导致形成通式为poly（NBE）_的多嵌段共聚物（ROMP）-共聚（NBE）_（VIP）-共聚（E）。预催化剂9的这一特殊特征，即诱导可逆的α-H消除/α-H加成反应的能力，归因于6- [2-（二乙基硼基）苯基]吡啶-2-基的独特作用配体。因此，缺乏该配体的模型前催化剂不具有诱导α-H消除/α-H加成反应的能力。各种二乙基硼基苯基吡啶-2-基胺和-酰胺的〜（11）B NMR位移不同，可以对这些化合物中B-N键的强度进行排名。 B-N键的强度与9 / MAO在不同温度下产生聚（NBE）_（ROMP）-共-聚（NBE）_（VIP）-共-聚（E）的倾向相关。

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