Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.
Department of Computer Science, University of California, Davis, Davis, California 95616, United States.
J Am Chem Soc. 2021 Apr 28;143(16):6060-6064. doi: 10.1021/jacs.1c02630. Epub 2021 Apr 16.
The activation of C-H bonds requires the generation of extremely reactive species, which hinders the study of this reaction and its key intermediates. To overcome this challenge, we synthesized an iron(III) chloride-pyridinediimine complex that generates a chlorine radical proximate to reactive C-H bonds upon irradiation with light. Transient spectroscopy confirms the formation of a Cl·|arene complex, which then activates C-H bonds on the PDI ligand to yield HCl and a carbon-centered radical as determined by photocrystallography. First-principles molecular dynamics-density functional theory calculations reveal the trajectory for the formation of a Cl·|arene intermediate. Together, these experimental and computational results show the complete reaction profile for the preferential activation of a C-H bond in the solid state.
C-H 键的活化需要生成极其活泼的物种，这阻碍了对该反应及其关键中间体的研究。为了克服这一挑战，我们合成了一种三价铁氯化物-吡啶二亚胺配合物，该配合物在光照下可生成紧邻反应性 C-H 键的氯自由基。瞬态光谱证实了 Cl·|芳烃配合物的形成，然后通过光结晶学确定该配合物可活化 PDI 配体上的 C-H 键，生成 HCl 和碳中心自由基。第一性原理分子动力学-密度泛函理论计算揭示了 Cl·|芳烃中间体形成的轨迹。这些实验和计算结果共同展示了在固态中优先活化 C-H 键的完整反应轮廓。
