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首页> 外文期刊>Chemistry: A European journal >(Thio)amidoindoles and (Thio)amidobenzimidazoles: An investigation of their hydrogen-bonding and organocatalytic properties in the ringopening polymerization of lactide
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(Thio)amidoindoles and (Thio)amidobenzimidazoles: An investigation of their hydrogen-bonding and organocatalytic properties in the ringopening polymerization of lactide

机译：（Thio）amidoindoles和（Thio）amidobenzizimidazoles：丙交酯开环聚合中氢键和有机催化性能的研究

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摘要

The mechanism of the ringopening polymerization (ROP) of lactide catalyzed by two partner hydrogen-bonding organocatalysts was explored. New amidoindoles 4a,c, thioamidoindoles 4b,d, amidobenzimidazoles 5a,c, and thioamidobenzimidazoles 5b,c were synthesized and used as activators of the monomer. In the solid state and in solution, compounds 4 and 5 showed a propensity for self-association, which was evaluated. (Thio)Amides 4 and 5 do catalyze the ROP of lactide in the presence of a cocatalyst, tertiary amine 3 a or 3 b, which activates the growing polymer chain through hydrogen-bonding. Reactions were conducted in 2-24 h at 20 °C; conversion yields ranged between 22 and 100 %. A detailed study of the intermolecular interactions undertaken be-tween the participating species showed that, as expected, simultaneous weak hydrogen bonds do exist to activate the reagents. Moreover, interactions have been revealed between the partner catalysts 4/5+3. ROP catalyzed by these partner activators is thus governed by multiple dynamic equilibria. The latter should be judiciously adjusted to finetune the catalytic properties of (thio)amides and organocatalysts, more generally.
机译：探索了两种配氢键有机催化剂催化的丙交酯开环聚合（ROP）机理。合成了新的酰胺基吲哚4a，c，硫酰胺基吲哚4b，d，酰胺基苯并咪唑5a，c和硫酰胺基苯并咪唑5b，c，并将其用作单体的活化剂。在固态和溶液中，化合物4和5表现出自缔合的倾向，对此进行了评估。 （硫代）酰胺4和5在助催化剂叔胺3a或3b的存在下催化丙交酯的ROP，其通过氢键激活正在生长的聚合物链。反应在20°C下2-24小时内进行;转化率在22％至100％之间。对参与物种之间进行的分子间相互作用的详细研究表明，与预期的一样，确实存在同时存在的弱氢键来激活试剂。此外，已经揭示了助催化剂4/5 + 3之间的相互作用。这些伙伴激活剂催化的ROP因此受多种动态平衡支配。应当明智地调整后者，以更一般地微调（硫代）酰胺和有机催化剂的催化性能。

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