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

Rong Li, Jinlei Tian, Hui Liu, Shiping Yan, Shouwu Guo, Jingyan Zhang

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

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 singlecrystal 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.

Original languageEnglish (US)
Pages (from-to)811-817
Number of pages7
JournalTransition Metal Chemistry
Volume36
Issue number8
DOIs
StatePublished - Nov 1 2011
Externally publishedYes

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