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

• 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
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17350019/
• 关键词: biradicals; spin-multiplicity; spin chemistry; quantum chemical calculations; molecular structure; reactive intermediate

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.

化学涉及键合和键形成。单元Diradicals是均质过程中的关键中间体。通常，反应性中间体是非常短暂的，因此在很大程度上难以捉摸，并且没有机会对分子进行反应。最近针对稳定单元diradicals的研究提供了一些机会来检查这种电子和结构独特的分子的化学性质。在这项合并的理论和实验研究中，我们发现了氮原子对单氮寿命的显着影响2,2 - 二甲氧基环烷-1,3-二烯基和分子间反应性。在计算上，计算出含氮的单元的圆锥类作用在能量上比相应的环闭合化合物更稳定。五元环系统中氮原子的引入有效地增加了单链2,2-二甲氧基丙烷-1,3-二烯基的寿命为毫秒级。发现极度长的单线1,3二元论可以与PTAD进行分子反应，以负担得起环加成产品。揭示了分子内反应性的1,2-氧迁移反应。这些显着的发现应刺激未来的计算和实验，对极寿命的单元派diradicals的新反应性，尤其是单曲线的分子间反应。

项目成果

Notable temperature effect on the stereoselectivity in the photochemical [2+2] cycloaddition reaction (Paterno-Buchi reaction) of 2,3-dihydrofuran-3-ol derivatives with benzophenone

• DOI: 10.1016/j.tetlet.2006.02.046
• 发表时间: 2006-04-10
• 期刊: TETRAHEDRON LETTERS
• 影响因子: 1.8
• 作者: Abe, M;Terazawa, M;Hayashi, T
• 通讯作者: Hayashi, T

Experimental Prob for Hyperconjugative Resonance Contribution in Stabilizing the Singlet State of 2,2-Dialkoxy-1,3-diyls : Regioselective 1,2-Oxygen Migration

超共轭共振对稳定 2,2-二烷氧基-1,3-二基单线态贡献的实验探讨：区域选择性 1,2-氧迁移

• 发表时间: 2007
• 期刊: J.Am.Chem.Soc. 128-24
• 作者: Goto;K.;Kawashima;T.;K.Shimada;K.Goto;Manabu ABE
• 通讯作者: Manabu ABE

An Extremely Long-lived Singlet 4,4-Dimethoxy-3,5-diphenylpyrazoline-3,5-diyl Derivative : A Notable Nitrogen Atom Effect on Intra- and Intermolecular Reactivity

一种极长寿命的单线态 4,4-二甲氧基-3,5-二苯基吡唑啉-3,5-二基衍生物：氮原子对分子内和分子间反应性的显着影响

• 发表时间: 2006
• 期刊: Angew. Chem. Int Ed. 45・46
• 作者: Abe;M.;Kubo;E.;K.Nozaki
• 通讯作者: K.Nozaki

A matrix isolation study of 2-isopropylidenecyclopentane-1,3-diyl (Berson-type diradical)

• DOI: 10.1021/jo060587l
• 发表时间: 2006-08-18
• 期刊: JOURNAL OF ORGANIC CHEMISTRY
• 影响因子: 3.6
• 作者: Abe, Manabu;Kawanami, Satoshi;Hayashi, Takashi
• 通讯作者: Hayashi, Takashi