Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby BC V5A 1S6, Canada.
Chem Commun (Camb). 2021 Apr 22;57(33):4007-4010. doi: 10.1039/d1cc00649e.
The photochemical activation of carbon-hydrogen bonds by vanadium(v)-dioxo and vanadium(v)-oxo-peroxo diimine complexes is described. Reactions were carried out using a selection of organic substrates with C-H bond dissociation free energy values between 70 and 97 kcal mol-1. The ability to activate C-H bonds using vanadium(v)-dioxo and vanadium(v)-oxo-peroxo diimine complexes varies with different bond dissociation free energy. Compounds with weaker C-H bonds are oxidized in minutes, rather than in days for thermal oxidations by the corresponding complexes. Dioxygen is necessary for substrate consumption, which suggests that the electronically excited V complexes are radical reaction initiators via H-atom abstraction from the organic substrate.
本文描述了钒（V）-二氧和钒（V）-氧过氧二亚胺配合物对碳-氢键的光化学激活。反应使用具有 C-H 键离解自由能值在 70 至 97 kcal mol-1 之间的一系列有机底物进行。使用钒（V）-二氧和钒（V）-氧过氧二亚胺配合物激活 C-H 键的能力因不同的键离解自由能而有所不同。对于较弱的 C-H 键，化合物在几分钟内被氧化，而不是在热氧化中对应配合物需要数天。氧气是底物消耗所必需的，这表明电子激发的 V 配合物通过从有机底物中提取 H 原子是自由基反应的引发剂。
