The first chiral tetracarbene indium(III) complexes have been synthesized by employing a rigid dianionic macrocyclic tetra-NHC ligand. The macrocyclic indium tetra-NHC bromide and ethoxide complexes are structurally similar to analagous salen complexes. The indium ethoxide complex effectively promotes living ring-opening polymerization of ε-caprolactone at room temperature.

中文翻译：

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ε-己内酯与大环四卡宾铟络合物的开环聚合


第一个手性四卡宾铟 （III） 配合物是通过采用刚性二离子大环四 NHC 配体合成的。大环四溴化铟和乙醇络合物在结构上与模拟 salen 络合物相似。铟乙醇络合物在室温下有效促进 ε-己内酯的活开环聚合。