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在水溶液中,非海姆Fe(IV) = O复合物的氧化还原潜力和C-H键裂解特性
Dong Wang1, Mo Zhang, Philippe Bühlmann
1Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Journal of the American Chemical Society
|May 19, 2010
概括
这项研究表明,质子显著影响高价值铁氧复合物的氧化还原特性,在这种类化合物中首次实现可逆电化学. 这些发现突出了这些铁氧物种在C-H键氧化中的独特反应性.
科学领域:
- 生物有机化学 生物有机化学
- 有机金属化学 有机金属化学
- 电化学 电化学 电化学
背景情况:
- 高价值铁氧中间体是非血酶催化过程中至关重要的氧化剂.
- 合成的Fe (IV) = O复合物,如[Fe (IV) (O) (N4Py) ] (N2+),为C-H键裂解提供了表征稳定性和反应性.
- 这些复合物的氧化还原特性,特别是质子的影响,仍然未被充分探索.
研究的目的:
- 为了研究质子对合成铁氧复合物[Fe(IV) ((O) ((N4Py)) ((2+)) 的氧化还原特性的影响.
- 探索这个复合体在非水和水溶液中的电化学行为.
- 了解这些氧化还原特性对C-H键氧化反应活性的影响.
主要方法:
- 电化学研究,包括循环电压测量,在各种溶剂 (乙尼和水) 中进行.
- 在水溶液中研究了C-H键氧化反应.
- 热力学稳定性和反应性通过结构特征和运动测量来评估.
主要成果:
- 在水溶液中观察到可逆的Fe(IV/III) 电化学反应 (E(1/2) =+0.41 V与pH 4的SCE相比),涉及电子和质子转移以形成Fe(III) -OH物种.
- 这代表了非血氧铁 (IV) 复合物的可逆电化学的第一个实例.
- 发现C-H键的氧化率取决于C-H键强度,但独立于溶剂,N4Py联体赋予了动力优势.
结论:
- 质子化可逆调节[Fe(IV) ((O) ((N4Py) ] ((2+) 复合物的氧化还原潜力,使稳定的电化学观测成为可能.
- 从该复合体中衍生出的Fe(III) -OH物种的计算D(O-H) 值为78(2) kcal mol(-1).
- 与其他氧化剂相比,N4Py配体环境提高了铁氧复合物的C-H键裂解效率.
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