State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China.
Nat Commun. 2014 Dec 5;5:5687. doi: 10.1038/ncomms6687.
The development of efficient processes for CO2 transformation into useful products is a long-standing goal for chemists, since CO2 is an abundant, inexpensive and non-toxic renewable C1 resource. Here we describe the enantioselective copolymerization of 3,4-epoxytetrahydrofuran with CO2 mediated by biphenol-linked dinuclear cobalt complex, affording the corresponding polycarbonate with >99% carbonate linkages and excellent enantioselectivity (up to 99% enantiomeric excess). Notably, the resultant isotactic polycarbonate is a typical semicrystalline polymer, possessing a melting point of 271 °C. Furthermore, the enantioselective terpolymerization of 3,4-epoxytetrahydrofuran, cyclopentene oxide and CO2 mediated by this dinuclear cobalt complex gives novel gradient polycarbonates, in which the decrement of one component and the increment of the other component occur sequentially from one chain end to the other end. The resultant terpolymers show perfectly isotactic structure and have unique crystalline-gradient nature, in which the crystallinity continuously varies along the main chain.
将二氧化碳转化为有用产品的高效工艺的开发是化学家的长期目标，因为二氧化碳是一种丰富、廉价且无毒的可再生 C1 资源。在这里，我们描述了双酚连接的双核钴配合物介导的 3,4-环氧四氢呋喃与 CO2 的对映选择性共聚，得到了相应的碳酸酯，具有 >99%的碳酸酯键和优异的对映选择性（高达 99%的对映过量）。值得注意的是，所得的全同立构聚碳酸酯是一种典型的半结晶聚合物，具有 271°C 的熔点。此外，通过这种双核钴配合物介导的 3,4-环氧四氢呋喃、环戊烯氧化物和 CO2 的对映选择性三元共聚得到了新型梯度聚碳酸酯，其中一种组分的减少和另一种组分的增加从链的一端到另一端顺序发生。所得的三元共聚物具有完美的全同立构结构，并具有独特的结晶梯度性质，其中结晶度沿主链连续变化。
