A mild and low‐temperature synthesis of nylon‐6 is achieved through the ring‐opening polymerization of ϵ‐caprolactam using barium σ‐borane complex as the catalyst. Due to the mild nature of the catalyst, this protocol provides an easy means of synthesizing nylon‐6, for the first time with a precise and predictable molecular weight. From various model experiments, it is evident that the σ‐coordinated boron hydride acts as a mild hydride donor in the first step of the reaction to generate lactamate anions, which then undergo ring‐opening polymerization in‐situ with the remaining caprolactam molecules under the influence of the dehydrogenated boron metal complex.

中文翻译：

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钡-硼烷配合物在温和条件下将ϵ-己内酰胺聚合为尼龙-6

尼龙6的轻度和低温合成是通过使用σ-硼烷钡配合物催化ε-己内酰胺的开环聚合而实现的。由于催化剂的温和性质，该方案首次提供了一种精确且可预测的分子量的合成尼龙-6的简便方法。从各种模型实验中可以明显看出，在第一步反应中，σ配位的硼氢化物充当温和的氢化物供体，生成内酰胺阴离子，然后与剩余的己内酰胺分子在其中进行开环聚合。脱氢硼金属配合物的影响。