一个与结合的的单电子氧化发生在协同的质子合电子转移中
1Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195, USA.
Journal of the American Chemical Society
|October 8, 2004
概括
在氧化一种与结合的,HOAr-NH2.2的过程中观察到与质子合的电子转移 (PCET). 这种反应涉及同时的电子和质子转移,排除了阶段性机制.
科学领域:
- 有机化学 有机化学
- 物理化学 物理化学
- 化学动力学 化学动力学
背景情况:
- 与结合的在各种化学和生物系统中至关重要.
- 了解电子和质子转移机制是反应化学的基础.
研究的目的:
- 为了研究2-(aminodiphenylmethyl) -4,6-di-tert-butylphenol (HOAr-NH2) 的氧化机制.
- 为了确定反应是否通过阶段或协同的质子合电子转移 (PCET) 进行.
主要方法:
- 氧化HOAr-NH2使用一种电子氧化剂,如三p-tolyl) 氨 ([N(tol) 3*+).
- 动力学研究包括平衡常数 (Keq),速率常数 (k) 和初级动力同位素效应 (kH/kD) 的确定.
- 使用马库斯理论分析速率常数对驱动力的依赖.
主要成果:
- 氧化产物是一个具有向氨基 (*OAr-NH3+) 转移质子的基.
- 动力学研究显示了具有显著初级同位素效应的二次动力学 (kH/kD = 2.4 +/- 0.4).
- 数据强烈支持协调的PCET机制,不包括逐步电子或质子转移途径.
结论:
- HOAr-NH2的氧化通过协同的质子合电子转移 (PCET) 机制进行.
- 对于电子转移过程,确定了一个大的内在激活屏障 (lambda = 34 kcal mol-1).
- 这些发现为控制PCET反应的基本步骤提供了关键的见解.
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