一个μ-1,2-超氧二铜 (II) 复合物的原子抽象热力学
Nicole Kindermann1, Can-Jerome Günes1, Sebastian Dechert1
1Universität Göttingen , Institut für Anorganische Chemie, Tammannstraße 4, D-37077 Göttingen, Germany.
Journal of the American Chemical Society
|July 11, 2017
概括
一个基于pyrazolate的二铜 (II) 复合物被氧化成一个稳定的μ-1,2-超二铜 (II) 复合物. 这种超氧复合物参与了原子抽象,揭示了铜氧化学的洞察力.
科学领域:
- 无机化学
- 协调化学
- 生物有机化学
背景情况:
- 铜氧复合物在生物系统和催化过程中至关重要.
- 了解过氧和超氧二铜物种的反应性对于模仿酶活性位点至关重要.
研究的目的:
- 合成和表征一个基于pyrazolate的μ-1,2-peroxo双铜 (II) 复合物.
- 研究该复合物的电化学氧化和随后的反应性.
- 阐明涉及双铜氧物种的原子抽象的机制和热力学.
主要方法:
- 电化学氧化μ-1,2-氧二铜 (II) 复合物.
- 由此产生的μ-1,2-超二铜 (II) 复合物的光谱表征 (IR光谱).
- 密度函数理论 (DFT) 计算用于结构和电子分析.
- 原子抽象反应的动力学和热力学分析.
- 热力学方程分析
主要成果:
- 在 -0.59 V 与 Fc/Fc+ 的情况下,将基于pyrazolate的μ-1,2-peroxo dicopper ((II) 复合物 (1) 氧化为稳定的μ-1,2-superoxo dicopper ((II) 复合物 (3).
- 光谱鉴定证实了超氧物种的形成 (ν̃(O-O) = 1070 cm−1, Δ(18O-16O) = -59 cm−1).
- 复合物3是通过从μ-1,1-水二铜复合物中抽取H原子而形成的,并且也可以从TEMPO-H中抽取H原子来再生2.
- 为这些H原子抽象过程确定了协同的质子电子转移途径.
- 在复合体 2 中,测定了 71.7 ± 1.1 kcal mol-1 的 OO-H 化合物解离的自由能量.
结论:
- 该研究成功合成并表征了一种稳定的μ-1,2-超二铜 (II) 复合物.
- 超氧复合物的电化学和化学反应性为铜-氧中间体提供了洞察力.
- 这些发现支持二铜氧物种在H原子抽取中协调的质子电子转移机制,对催化循环有影响.
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