Cycloaddition of epoxides and CO2 catalyzed by bisimidazole-functionalized porphyrin cobalt(III) complexes
Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC00370B, Paper
DOI: 10.1039/C6GC00370B, Paper
Xu Jiang, Faliang Gou, Fengjuan Chen, Huanwang Jing
Bisimidazole-functionalized cobaltoporphyrin acted as efficient bifunctional catalysts to facilitate the synthesis of cyclic carbonates from epoxides and CO2.
Bisimidazole-functionalized cobaltoporphyrin acted as efficient bifunctional catalysts to facilitate the synthesis of cyclic carbonates from epoxides and CO2.
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Cycloaddition of epoxides and CO2 catalyzed by bisimidazole-functionalized porphyrin cobalt(III) complexes
*Corresponding authors
aState Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering Lanzhou University, Gansu 730000, PR China
bState Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, P R China
E-mail: hwjing@lzu.edu.cn
E-mail: hwjing@lzu.edu.cn
Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC00370B
A series of innovative bisimidazole-functionalized porphyrin cobalt(III) complexes have been devised, synthesized and characterized using NMR, MS and elemental analysis. These homogeneous catalysts were applied to the cycloaddition of epoxides and carbon dioxide without organic solvent and co-catalyst. It was found that the performance of the catalysts deeply relies on their structural features. The alkoxyl chain length of the linkage and the imidazole position relative to the phenyl rings of porphyrin evidently affects the catalyst activities. [5,15-Di(3-((8-imidazolyloctyl)oxy)phenyl)porphyrin] cobalt(III) chloride (J-m8) and [5,15-di(2-((6-imidazolylhexyl)oxy)phenyl)porphyrin] cobalt(III) chloride (J-o6) demonstrated excellent activity under optimal reaction conditions. Synchronously, a preliminary kinetic investigation of this reaction was carried out using three catalysts and illustrated the activation energies of cyclic carbonate formation. Furthermore, a tri-synergistic catalytic mechanism has been carefully proposed in light of the features of the new catalysts and experimental results.
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///Cycloaddition of epoxides, CO2 catalyzed, bisimidazole-functionalized porphyrin cobalt(III) complexes