C−H Activation by a Mononuclear Manganese(III) Hydroxide Complex: Synthesis and Characterization of a Manganese-Lipoxygenase Mimic?
作者:Christian R. Goldsmith、Adam P. Cole、T. Daniel P. Stack
DOI:10.1021/ja039283w
日期:2005.7.13
chemistry. Thermodynamic analysis of [Mn(III)(PY5)(OH)](2+) and the reduced product, [Mn(II)(PY5)(H(2)O)](2+), estimates the strength of the O-H bond in the metal-bound water in the Mn(II) complex to be 82 (+/-2) kcal mol(-)(1), slightly less than that of the O-H bond in the related reduced iron complex, [Fe(II)(PY5)(MeOH)](2+). [Mn(III)(PY5)(OH)](2+) reacts with hydrocarbon substrates at rates comparable
脂氧合酶是单核非血红素金属酶,可将含 1,4-戊二烯亚基的脂肪酸区域和立体特异性地转化为烷基过氧化物。通常认为限速步骤是通过活性金属 (III)-氢氧化物物种从底物的戊二烯亚单元中夺取氢原子,得到金属 (II)-水物种和有机基团。所有已知的植物和动物脂肪氧化酶都含有铁作为活性金属;然而,最近发现锰是真菌脂肪氧化酶中的活性金属。这里报告的是单核 Mn(III) 复合物的合成和表征,[Mn(III)(PY5)(OH)](CF(3)SO(3))(2) (PY5 = 2,6-bis(双(2-吡啶基)甲氧基甲烷)吡啶),以与氢原子提取最一致的方式与烃底物反应,并为所提出的反应机制提供化学优先权。PY5 的中性五吡啶基连接赋予金属中心强路易斯酸性特征,允许 Mn(III) 化合物进行这种氧化化学反应。[Mn(III)(PY5)(OH)](2+) 和还原产物 [Mn(II)(PY5)(H(2)O)](2+)