The ability to control the outcome of polymerisations using an external stimulus remains a formidable challenge. Herein, we report a series of photoactive Schiff base ligands bearing azobenzene moieties, as well as seven Al(III) and Zn(II) complexes. Trans–cis isomerisation of the ligands and complexes occurred by exposure to UV light. Photoisomerisation was investigated using spectroscopic techniques and real-time reaction monitoring was conducted using FlowNMR. The activity of the complexes was tested in ring-opening polymerisation (ROP) of ε-caprolactone and rac-lactide under ambient and UV light conditions, with the isomers of the Al(III) complexes displaying marked differences in activity in the ROP of ε-caprolactone.

中文翻译：

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含偶氮苯的配体的铝（III）和锌（II）配合物，用于ε-己内酯和外消旋丙交酯的开环聚合

利用外部刺激控制聚合结果的能力仍然是一个巨大的挑战。在这里，我们报告一系列带有偶氮苯部分的光敏席夫碱配体，以及七个Al（III）和Zn（II）配合物。配体和配合物的反式-顺式异构化是通过暴露于紫外线下而发生的。使用光谱技术研究了光异构化，并使用FlowNMR进行了实时反应监测。在环境和紫外光条件下，用Al（III）的异构体在ε-己内酯和外消旋丙交酯的开环聚合（ROP）中测试了络合物的活性。）复合物在ε-己内酯的ROP中显示出明显的活性差异。