Phosphazenes as organocatalysts for the synthesis of polymers have evolved to powerful tools, and their catalytic performances highly depend on the basicity and molecular structure (size and shape). Therefore, designing phosphazenes with tunable basicity and molecular structure is greatly promising for the development of organocatalysts with improved catalytic properties, for example, high activity and selectivity. In this contribution, 2,4,6-tris[tri(dimethylamino)iminophosphorane]-1,3,5-triazine (C₃N₃-Me-P₃) and 2,4,6-tris[tri(1-pyrrolidinyl)iminophosphorane]-1,3,5-triazine (C₃N₃-Py-P₃) containing a 1,3,5-triazine-core were designed and synthesized. NMR spectroscopy analysis and single-crystal X-ray diffractions reveal that C₃N₃-Me-P₃ and C₃N₃-Py-P₃, particularly the latter, show relatively low basicity, similar as t-BuP₁, but have a bulky molecular size, similar as t-BuP₄. C₃N₃-Me-P₃ and C₃N₃-Py-P₃ were successfully employed as organocatalysts for the ring-opening alternating copolymerization (ROAC) of anhydrides and epoxides with high activity. The produced polyesters were characterized using NMR spectroscopy, GPC and MALDI TOF, revealing perfectly alternating sequence, controlled molar mass and low dispersity and suggesting highly controlled ROAC reactions. Thus, well-defined triblock polyester P(PA-alt-CHO)-b-P(PA-alt-PO)-b-P(PA-alt-CHO) was facilely synthesized by one-pot reaction via sequential addition of two different epoxides.

中文翻译：

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以三嗪为核心的三-磷腈碱的合成及其在环氧化物和酸酐的高效开环交替共聚中的应用：碱度和分子量的显着影响

磷腈作为合成聚合物的有机催化剂已发展成为强大的工具，其催化性能高度依赖于碱度和分子结构（大小和形状）。因此，设计具有可调碱度和分子结构的磷腈对于开发具有改进催化性能（例如，高活性和选择性）的有机催化剂具有很大的前景。在此贡献中，2,4,6-tris[tri(dimethylamino)iminophorane]-1,3,5-triazine (C ₃ N ₃ -Me-P ₃ ) 和 2,4,6-tris[tri(1-吡咯烷基）亚氨基正膦]-1,3,5-三嗪（C ₃ N ₃ -Py-P ₃) 设计并合成了含有 1,3,5-三嗪核心的。NMR光谱分析和单晶X射线衍射表明C ₃ N ₃ -Me-P ₃和C ₃ N ₃ -Py-P ₃，特别是后者，显示出相对较低的碱度，类似于t -BuP ₁，但具有庞大的分子大小，类似于t -BuP ₄。C ₃ N ₃ -Me-P ₃和 C ₃ N ₃ -Py-P ₃成功地用作具有高活性的酸酐和环氧化物的开环交替共聚（ROAC）的有机催化剂。使用 NMR 光谱、GPC 和 MALDI TOF 对生产的聚酯进行了表征，揭示了完美的交替序列、可控的摩尔质量和低分散性，并表明 ROAC 反应高度可控。因此，通过一锅反应，通过顺序添加两种_不同的环氧化物。