<i>o</i>-Phenylene Halocarbenonitrenes and <i>o</i>-Phenylene Chlorocarbenocarbene: A Combined Experimental and Computational Approach
作者:Tomonori Enyo、Nobuaki Arai、Norio Nakane、Athanassios Nicolaides、Hideo Tomioka
DOI:10.1021/jo0512204
日期:2005.9.1
rene (2-HN). Compared to the parent 2-HN, halogen substitution stabilizes the A‘ ‘ states relative to the A‘ ones. Halogen substitution also affects the barrier and exothermicity of the ring-opening reaction (to form unsaturated nitriles 4-XN, X = F, Cl, Br), but it has a smaller effect on the ring-closing reaction (to form benzo(aza)cyclobutadiene 3-XN, X = F, Cl, Br). Attempts to generate and observe
计算发现,邻苯撑(卤)碳烯基氮烯2-XN,X = F,Cl,Br,具有诸如母体邻苯撑碳烯基戊二烯(2-HN)的单重双自由基基态。与母体2-HN相比,卤素取代可使A'状态相对于A'状态稳定。卤素取代也会影响开环反应的屏障和放热(形成不饱和腈4-XN,X = F,Cl,Br),但对闭环反应的影响较小(形成苯并(氮杂)氮)环丁二烯3-XN,X = F,Cl,Br)。尝试生成和观察邻-亚苯基(卤)碳烯基氮烯2-XN,X = F,Cl,Br,在类似于成功观察2-HN的条件下使用基质分离光谱法失败。相反,观察到的光产物是3-XN和4-XN的混合物。在每种情况下,混合物的主要产物似乎是热力学上更稳定的产物。在X = Br的情况下,观察到的混合物包含一种假定为Z - 6-BrN的其他组分。还计算出邻苯二甲氯碳卡宾卡宾具有醌型单线双自由基基态和相对稳定的A''激发态。尝试在基质分离条件下生成双卡宾导致检测到