Cycloaddition of epoxides and CO2 catalyzed by bisimidazole-functionalized porphyrin cobalt(III) complexes

Cycloaddition of epoxides and CO2 catalyzed by bisimidazole-functionalized porphyrin cobalt(III) complexes

Green Chem., 2016, Advance Article
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.

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Cycloaddition of epoxides and CO₂ catalyzed by bisimidazole-functionalized porphyrin cobalt(III) complexes

Xu Jiang,^a   Faliang Gou,^a   Fengjuan Chen^a and  Huanwang Jing*^ab  

 *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

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.

References [1] L. Jin, H. Jing, T. Chang, X. Bu, L. Wang and Z. Liu, J. Mol. Catal. A: Chem., 2007, 261, 262. [2] X. Jiang, F. Gou and H. Jing, J. Catal., 2014, 313, 159. [3] B. Li, L. Zhang, Y. Song, D. Bai and H. Jing, J. Mol. Catal. A: Chem., 2012, 363– 364, 26.

///Cycloaddition of epoxides,   CO2 catalyzed,  bisimidazole-functionalized porphyrin cobalt(III) complexes