State Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University , Tianjin, 300071, China.
Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University , Beijing, 100084, China.
Chem Rev. 2017 Jul 12;117(13):8622-8648. doi: 10.1021/acs.chemrev.6b00664. Epub 2017 Mar 10.
The most fundamental concepts in chemistry are structure, energetics, reactivity and their inter-relationships, which are indispensable for promoting chemistry into a rational science. In this regard, bond energy, the intrinsic determinant directly related to structure and reactivity, should be most essential in serving as a quantitative basis for the design and understanding of organic transformations. Although C-H activation/functionalization have drawn tremendous research attention and flourished during the past decades, understanding the governing rules of bond energetics in these processes is still fragmentary and seems applicable only to limited cases, such as metal-oxo-mediated hydrogen atom abstraction. Despite the complexity of C-H activation/functionalization and the difficulties in measuring bond energies both for the substrates and intermediates, this is definitely a very important issue that should be more generally contemplated. To this end, this review is rooted in the energetic aspects of C-H activation/functionalization, which were previously rarely discussed in detail. Starting with a concise but necessary introduction of various classical methods for measuring heterolytic and homolytic energies for C-H bonds, the present review provides examples that applied the concept and values of C-H bond energy in rationalizing the observations associated with reactivity and/or selectivity in C-H activation/functionalization.
化学中最基本的概念是结构、能量学、反应性及其相互关系，这些对于将化学推进到一个理性的科学是不可或缺的。在这方面，键能作为与结构和反应性直接相关的内在决定因素，应该是作为设计和理解有机转化的定量基础的最基本的因素。尽管 C-H 活化/功能化在过去几十年中引起了极大的研究关注并蓬勃发展，但对于这些过程中键能的控制规律的理解仍然是零碎的，似乎只适用于有限的情况，例如金属-氧介导的氢原子提取。尽管 C-H 活化/功能化非常复杂，并且难以测量底物和中间体的键能，但这绝对是一个非常重要的问题，应该更普遍地加以考虑。为此，本综述立足于 C-H 活化/功能化的能量方面，这些方面以前很少详细讨论过。从简要但必要的介绍各种经典方法来测量 C-H 键的异裂和均裂能开始，本综述提供了一些例子，应用了 C-H 键能的概念和值来合理化与 C-H 活化/功能化的反应性和/或选择性相关的观察结果。
