Halogen Photoelimination from SbV Dihalide Corroles.
Halogen Photoelimination from SbV Dihalide Corroles.
复制标题
SbV 二卤化物 Corroles 的卤素光消除。
作者：
Christopher M. Lemon;S. Hwang;Andrew G. Maher;D. Powers;D. Nocera
主族p嵌段金属非常适合于介导双电子反应，因为它们在mn和mn +2氧化还原态之间循环，因为单电子态是热力学不稳定的。本文报道了一种SbIII衍生物及其SbVX2 （X = Cl, Br）同系物的合成和结构。SbIII位于柯罗环上方，而SbV位于柯罗质心。电化学表明SbIII和SbVX2之间存在相互转化。TD-DFT计算表明，在Soret光谱区激发态为HOMO→LUMO+2，相对于Sb-X片段具有显著的反键特征。THF中2和3的光化学反应与计算结果一致，因为在与SbVX2的Soret吸收波长一致的稳态光解导致其干净地转化为SbIII的光化学反应。这种光激活Sb-X键的能力反映了致烟原倾向于依靠PnIII/V偶来驱动M-X键激活的双电子光化学反应，这是发展hx分裂循环所需的基本转变。
Main-group p-block metals are ideally suited for mediating two-electron reactions because they cycle between M n and M n+2 redox states, as the one-electron state is thermodynamically unstable. Here, we report the synthesis and structure of an SbIII corrole and its SbVX2 (X = Cl, Br) congeners. SbIII sits above the corrole ring, whereas SbV resides in the corrole centroid. Electrochemistry suggests interconversion between the SbIII and SbVX2 species. TD-DFT calculations indicate a HOMO → LUMO+2 parentage for excited states in the Soret spectral region that have significant antibonding character with respect to the Sb-X fragment. The photochemistry of 2 and 3 in THF is consistent with the computational results, as steady-state photolysis at wavelengths coincident with the Soret absorption of SbVX2 corrole lead to its clean conversion to the SbIII corrole. This ability to photoactivate the Sb-X bond reflects the proclivity of the pnictogens to rely on the PnIII/V couple to drive the two-electron photochemistry of M-X bond activation, an essential transformation needed to develop HX-splitting cycles.