文献类型：期刊文献

英文题名：Coordination modes of bridge carboxylates in dinuclear manganese compounds determine their catalase-like activities

作者：Jiang, Xiaojun[1];Liu, Hui[1];Zheng, Bing[1];Zhang, Jingyan[1,2]

机构：[1]E China Univ Sci & Technol, Sch Pharm, Dept Pharmaceut Sci, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2009

期号：40

起止页码：8714

外文期刊名：DALTON TRANSACTIONS

收录：;EI(收录号：20103513189156);WOS:【SCI-EXPANDED(收录号:WOS:000270593400031)】；

基金：The authors gratefully acknowledge the National Science Foundation (No. 20671034) and Shanghai Pujiang Scholarship Program (No. 06PJ14030) for financial support.

语种：英文

外文关键词：Catalyst activity - Carboxylation - Manganese compounds - Ions - Electron spin resonance spectroscopy - Deprotonation - X ray diffraction

摘要：To explore the role of bridge carboxylate coordination modes on the catalase-like activities of dinuclear manganese compounds, [Mn-2(II)(bpmapa)(2)(H2O)(2)](ClO4)(2) (1), [Mn-2(II)(pbpmapa)(2)(H2O)(2)](ClO4)(2) (2), and [Mn-2(II)(bpmaa)(2)(H2O)(3)](ClO4)(2) (3) (bpmapa = [bis(2-pyridylmethyl)amino]propionic acid, pbpmapa = alpha-phenyl-beta-[bis(2-pyridylmethyl)amino]propionic acid, and bpmaa = [bis(2-pyridylmethyl)amino]aceticacid), in which Mn-II-Mn-II centers have a similar coordination sphere but different carboxylate-Mn bridging modes have been synthesized and structurally characterized by single X-ray diffraction, UV-visible, IR, and EPR spectroscopies, and their catalase-like activities were investigated. Studies of their catalytic activities and the influence of the nitrogenous bases on their catalytic activities indicated that the carboxylate-Mn coordination mode was crucial in H2O2 deprotonation, and eventually in H2O2 disproportionation. Compound 1 with a bidentate carboxylate bridge showed higher catalase-like activity than 2 and 3, in which the carboxylate groups have a monodentate bridging mode. The deprotonation ability of the carboxylate anion was determined by the O-C-O angle and the distance between the weakly bound oxygen of the bridging carboxylate to the manganese ion. The smaller the angle, and the shorter the distance, the stronger the basicity that the carboxylate anion exhibits. The bidentate mu-1,1 bridging coordination mode functionally mimicked the glutamate residues at the manganese catalase active site. Our results suggested that increasing the basicity of the bridging carboxylate ligand of the catalase model compounds will increase their deprotonation ability and lead to more active catalase mimics.