试验证据为终端Co (III) -Oxo复合物的CH激活中pKa-驱动的异步
McKenna K Goetz1, John S Anderson1
1Department of Chemistry , University of Chicago , Chicago , Illinois 60637 , United States.
Journal of the American Chemical Society
|February 12, 2019
概括
这项研究表明,氧复合物的C-H激活反应是由基质酸度 (pKa) 而不是C-H键强度决定的. 这表明过渡金属oxo复合物的新"异步"协同机制.
科学领域:
- 有机金属化学
- 氧化化学
- 催化剂
背景情况:
- 在生物和合成化学中,过渡金属氧复合物的C-H激活至关重要.
- 了解这些复合物的机制和反应模式对于推进氧化化学至关重要.
研究的目的:
- 为了研究合成的晚期过渡金属oxo复合物的C-H激活活性,PhB ((tBuIm) 3CoIII O.
- 确定控制该复合物的反应性的因素,特别是比较基质pKa和C-H键解离能 (BDE) 的影响.
主要方法:
- 对复合物的联合体进行 pKa 和 O-H 键解离能量的实验性确定.
- 用9,10-二甲烯测量反应的激活参数.
- 评估各种原子捐赠者的反应速率.
- 对CH激活机制的综合实验和计算分析.
主要成果:
- PhB ((tBuIm) 3CoIII O的反应性主要取决于基质的pKa,与既定范式形成鲜明对比.
- 测量了激活参数并与文献中的值进行了比较.
- 过渡状态分析显示了显著的质子转移特征.
结论:
- 通过pKa驱动的异步协同机制,而不是逐步的过程.
- 这一发现为过渡金属oxo复合物提出了一个新的反应模式,可能使C-H激活反应具有替代选择性.
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