高效的烯氧化,由[Mn(V) ((N) ((CN) 4 - 2)) 催化. 有证据表明[Mn{VII}{N}{O}{CN}4]{2-) 是一种活性中间体
1Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong , Tat Chee Avenue, Hong Kong, China.
Journal of the American Chemical Society
|May 7, 2014
概括
催化剂使用过氧化或氧化剂有效地将基氧化为酒精和. 动力学研究表明,一种涉及活性中间体的机制可以从中抽象原子.
科学领域:
- 无机化学 无机化学 有机化学
- 催化剂是一种催化剂.
- 有机合成 有机合成
背景情况:
- 烯氧化对于合成有价值的化学物质至关重要.
- 为基功能化开发高效和选择性的催化剂仍然是一个重大挑战.
- 复合物在各种氧化反应中表现为有前途的催化剂.
研究的目的:
- 使用[Mn(V) ((N) ((CN) 4)) 2-) 复合体来研究基的催化氧化.
- 探索不同终端氧化剂的有效性,包括过氧化和 (IV) 酸.
- 通过动力学研究和光谱分析阐明反应机制.
主要方法:
- 催化氧化反应在室温下进行.
- 过氧化 (H2O2) 和二 (IV) 酸盐 (NH4) 2 (Ce) (NO3) 6被用作氧化剂.
- 动态同位素效应 (KIE) 用环素及其化模拟物 (环素-d12) 进行测量.
- 电子喷雾电离质谱法 (ESI-MS) 用于识别反应中间体.
- 密度函数理论 (DFT) 的计算被用来支持拟议的机制.
主要成果:
- 使用 H2O2 在三乙醇 (CF3CH2OH) 中获得了优异的酒精和的产量 (>95%).
- 在CF3CH2OH/H2O混合物中使用Ce (IV) 获得了良好的产量 (>80%).
- KIE值为3.1 ± 0.3 (H2O2) 和3.6 ± 0.2 (Ce(IV)) 表明最初限制速度的H原子抽象.
- 在ESI-MS检测到一种酸酸盐的氧化物种,表明一种活性中间体.
- DFT的计算证实了拟议的反应路径.
结论:
- [Mn{V}{N}{CN}4]{2-) 复合物是氧化的一个有效催化剂.
- 反应过程通过初始O原子转移形成 ((VII) 酸氧物种,然后从中提取H原子.
- 提出的机制,涉及H原子抽象和O反弹,得到实验和计算数据的支持.
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