文献类型：期刊文献

英文题名：Direct evidence for the role of imidazole in disproportionation of hydrogen peroxide by a mononuclear manganese salen complex

作者：Li, Rong[1];Tian, Jinlei[2];Liu, Hui[1];Yan, Shiping[2];Guo, Shouwu[3];Zhang, Jingyan[1]

机构：[1]E China Univ Sci & Technol, Sch Pharm, Dept Pharmaceut Sci, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[2]Nankai Univ, Dept Chem, Tianjin 300071, Peoples R China;[3]Shanghai Jiao Tong Univ, Res Inst Micro Nano Sci & Technol, Natl Key Lab Micro Nano Fabricat Technol, Shanghai 200240, Peoples R China

年份：2011

卷号：36

期号：8

起止页码：811

外文期刊名：TRANSITION METAL CHEMISTRY

收录：;EI(收录号：20120314680818);WOS:【SCI-EXPANDED(收录号:WOS:000300082500004)】；

基金：This work was supported by the State Key Laboratory of Bioreactor Engineering (No. 2060204), 111 Project (B07023), and NSFC of P. R. China (Nos. 20671034 and 21001044).

语种：英文

外文关键词：Ultraviolet visible spectroscopy - Synthesis (chemical) - Manganese compounds - Oxidation - Catalyst activity - Ligands - X ray diffraction

摘要：It has long been known that imidazole can enhance the catalytic activity of catalase model compounds; however, the role of imidazole is still not well understood. In an attempt to elucidate the role of imidazole in promoting the disproportionation of hydrogen peroxide by model compounds, four mononuclear manganese salen (Mn-Salen) complexes with and without axial imidazole ligands were synthesized and characterized by single-crystal X-ray diffraction, UV-vis spectroscopy, electrochemical and HPLC measurements. By comparing the Mn-Salen compounds with and without imidazole ligands, we demonstrated that the activity enhancement of imidazole originated from coordination of imidazole to the manganese center when less than one equivalent of imidazole was present, and from assisted deprotonation of the substrate when excess imidazole was present. These results provide direct evidence for the mechanism of activity enhancement of imidazole in the catalysis of enzyme model compounds.