在rac-lactide聚合物的催化过程中,氧-亚佐配体的复合物
Pattarawut Sumrit1,2, Sirawan Kamavichanurat1,2, Wasan Joopor1,2
1Laboratory of Catalysts and Advanced Polymer Materials, Department of Chemistry and Centre of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand. fscipph@ku.ac.th.
新的氧复合物启动了rac-lactide的环开聚合. 这些催化剂表现出受控和活聚合,其中正氧替代剂减缓了反应速度.
科学领域:
- 有机金属化学 有机金属化学
- 聚合物化学 聚合物化学
背景情况:
- 复合物是有机合成和聚合过程中的多功能催化剂.
- 氧联体为金属复合提供独特的电子和硬质性质.
研究的目的:
- 为了合成和描述新型的氧-阿佐复合物.
- 调查它们作为rac-lactide环开放聚合物的启动剂的有效性.
- 阐明连接体结构对催化活性和机制的影响.
主要方法:
- 合成和表征14种新的二甲基和单甲基氧复合物.
- 进行X射线衍射分析,以确定代表性复合物的结构.
- 可变温度1HNMR光谱用于研究流动行为和确定激活参数.
- 动力学研究以确定反应顺序,以单体和启动剂度为准.
主要成果:
- 成功合成并对两个系列的氧-阿佐复合物的完整表征.
- 扭曲的四面体几何学通过X射线衍射证实复合体4a.
- 在复合体5b中观察到的流动性行为和同位素转换,并报告了详细的激活参数.
- 所有合成的复合物都表现出作为rac-lactide环开放聚合物的受控和活体启动剂的活性.
- 在二甲基和单甲基复合物之间,催化活性是可比的.
- 发现,由 орто-氧替代剂制成的固体阻碍减缓了聚合率.
- 动力学研究表明,一级依赖于单体和启动剂度.
- 与氧胺复合物相比,氧胺复合物的催化活性较低.
结论:
- 合成的氧复合物是对rac-lactide的受控和活环开放聚合物的有效发起者.
- 连接物结构,特别是固态因素,显著影响催化性能.
- 了解结构-活性关系为设计更高效的聚合催化剂提供了洞察力.
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