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New Development of Biradical Chemistry : Construction of a Novel Structure

双自由基化学的新进展：新型结构的构建

基本信息

批准号：
17350019
负责人：
ABE Manabu
金额：
$ 6.27万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

Chemistry involves bond-cleavage and bond formation. Singlet diradicals are key intermediates in homolytic processes. In general, the reactive intermediates are quite short-lived, and thus, largely elusive and have no chance to react intermolecularly. Recent studies, directed toward stabilizing singlet diradicals, have provided some opportunities to examine the chemistry of such electronically and structurally unique molecules.In this combined theoretical and experimental study, we found a notable effect of a nitrogen atom on the lifetime of singlet 2,2-dimethoxycyclopentane-1,3-diyls, and the intra-and intermolecular reactivity. Computationally, the nitrogen-containing singlet diradicals were calculated to be energetically more stable than the corresponding ring-closure compounds. The introduction of nitrogen atoms in the five-membered ring system effectively increased the lifetime of the singlet 2,2-dimethoxypropane-1,3-diyl to the millisecond time scale. The extremely long-lived singlet 1,3-diradical was found to react intermolecularly with PTAD to afford the cycloaddition product. A 1,2-oxygen migration reaction was revealed for intramolecular reactivity. These remarkable findings should stimulate future computations and experiments on the novel reactivity of extremely long-lived singlet diradicals, especially intermolecular reactions of singlet diradicals.

化学包括键的断裂和键的形成。单线态双自由基是均裂过程中的关键中间体。一般来说，活性中间体的寿命很短，因此很大程度上是难以捉摸的，没有机会在分子间反应。最近的研究，针对稳定单线态双自由基，提供了一些机会来检查这样的电子和结构独特的分子的chemicals.In这一结合的理论和实验研究，我们发现了一个显着的影响的单重态2，2-二甲氧基环戊烷-1，3-diyls的寿命，和分子内和分子间的反应性的氮原子。在计算上，含氮的单线态双自由基被计算为在能量上比相应的闭环化合物更稳定。在五元环系统中引入氮原子有效地将单线态2，2-二甲氧基丙烷-1，3-二基的寿命增加到毫秒时间尺度。发现寿命极长的单重态1，3-二自由基与PTAD发生分子间反应，得到环加成产物。一个1，2-氧迁移反应，揭示了分子内反应。这些显著的发现将刺激未来的计算和实验上的新反应的极长寿命的单线态双自由基，特别是分子间反应的单线态双自由基。