从黄金中减少淘汰的化物依赖机制 (III)
Matthew S Winston1, William J Wolf1, F Dean Toste1
1Department of Chemistry, University of California, Berkeley, California 94720, United States.
研究人员合成了新的有机金属化物复合物. 化物连接体的身份极大地影响了还原性消除中的反应性和选择性,Au(III) -X键强度是关键决定因素.
科学领域:
- 有机金属化学 有机金属化学
- 无机化学 无机化学
- 反应机制 反应机制
背景情况:
- 具有黄金 (III) 中心的有机金属复合物对催化应用具有兴趣.
- 减少性消除是许多涉及有机金属复合物的催化循环中的关键步骤.
- 了解控制减少性淘汰选择性的因素对于设计高效的催化剂至关重要.
研究的目的:
- 合成和描述新的金的有机金属化物复合物 (III).
- 为了研究降解性消除的机械路径,C(aryl) -X和C(aryl) -CF3键.
- 为了确定化物联体对反应性和选择性的影响.
主要方法:
- 素支持黄金的合成 (III) 有机金属化物复合物.
- 在122°C的温度下进行热解研究以监测反应动力学.
- 动力分析以确定反应顺序并确定催化效应.
- 对Au(III) -X键解离能量的热力学测量.
主要成果:
- 两个系列的复合物, (Ph3P) Au ((4-Me-C6H4) ((CF3) ((X) 和 (Cy3P) Au ((4-F-C6H4) ((CF3) ((X) 被合成 (X = I, Br, Cl, F).
- 发现还原性淘汰的反应性和动力选择性高度依赖于化物联体.
- 对于X = I或F,观察到零级动力学,而对于X = Cl或Br,则涉及产物催化.
- 对于C(aryl) -CF3键形成的选择性随着X = I < Br < Cl < F而增加.
- 对于X = I,仅发生C(aryl) -I消除,而对于X = F,仅发生C(aryl) -CF3消除.
- (III) -X键解离能量的增加依次为X = I < Br < Cl.
结论:
- 基态Au (III) -X键强度决定了C (aryl) -X和C (aryl) -CF3减少性消除的选择性.
- 化物连接体在控制反应路径和产品分布方面发挥着至关重要的作用.
- 这些发现提供了对黄金复合物的减少消除机制的基本见解.
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