Chemical Consequences of Arylnitrenes in the Crystalline Environment
Chemical Consequences of Arylnitrenes in the Crystalline Environment
复制标题
结晶环境中芳基氮烯的化学后果
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
T. Sugawara
中科院分区：
文献类型：
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作者：
Akito Sasaki;L. Mahe;A. Izuoka;T. Sugawara
几种芳基叠氮化合物的粉末晶体在低温下的紫外光分解主要得到偶氮化合物。在对-（N-甲基乙酰氨基）苯基叠氮和2-叠氮基联苯的情况下，形成CH插入产物或咔唑，与偶氮形成竞争。当考虑晶体结构时，这些产物可以被认为是通过拓扑过程形成的。在叠氮化物晶体中产生的芳基氮烯由ESR光谱监测;与气相或溶液中的芳基氮烯相比，它们具有极长的半衰期。这种高动力学稳定性归因于所产生的氮烯周围的惰性环境。芳氮烯在初始阶段的衰减过程服从伪一级动力学，活化参数进行了评估Arrhenius图。活化能谱和活化熵表明芳氮烯的扩散过程可能是决定反应动力学稳定性和产物分布的重要因素。
UV photolysis of powdered crystals of several aryl azides at cryogenic temperatures afforded azo compounds predominantly. In the cases of p-(N-methylacetamido)phenyl azide and 2-azidobiphenyl, a CH insertion product or a carbazole was formed, competing with azo formation. These products can be considered to be formed through topotactic processes when the crystal structures are taken into account. The arylnitrenes generated in the azide crystals were monitored by ESR spectroscopy; they turned out to have extremely long half life-times, compared with those in the gas phase or in solution. Such high kinetic stabilities are ascribed to the inert environment around the generated nitrenes. The decay process of arylnitrenes in the initial stage obeyed a pseudo-first order kinetics; activation parameters were evaluated by Arrhenius plots. The activation enthalpies and entropies indicate that the diffusional processes of arylnitrenes may be the vital factors determining the kinetic stability and the product distri...