TY - JOUR
T1 - Direct evidence for the role of imidazole in disproportionation of hydrogen peroxide by a mononuclear manganese salen complex
AU - Li, Rong
AU - Tian, Jinlei
AU - Liu, Hui
AU - Yan, Shiping
AU - Guo, Shouwu
AU - Zhang, Jingyan
PY - 2011/11/1
Y1 - 2011/11/1
N2 - 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.
AB - 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.
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U2 - 10.1007/s11243-011-9535-6
DO - 10.1007/s11243-011-9535-6
M3 - Article
AN - SCOPUS:84862924209
VL - 36
SP - 811
EP - 817
JO - Transition Metal Chemistry
JF - Transition Metal Chemistry
SN - 0340-4285
IS - 8
ER -