Design and Synthesis of New Stable Fluorenyl-Based Radicals
Design and Synthesis of New Stable Fluorenyl-Based Radicals
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DOI：
10.1021/ja507005c
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发表时间：
2014-09-10
影响因子：
15
通讯作者：
Kubo, Takashi
中科院分区：
文献类型：
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作者：
Tian, Yi;Uchida, Kazuyuki;Kubo, Takashi
有机中性自由基长期以来一直让化学家着迷，他们对有机反应中的结构反应性关系有基本的了解，并且作为新的功能材料的应用。然而，这些自由基的难以捉摸的性质使得合成、分离和表征非常具有挑战性。在这项工作中，报告了三种长寿命的芴基自由基的合成。除了密度泛函理论（DFT）计算之外，还结合各种实验方法系统地研究了这些自由基的几何形状和电子结构，其中包括X射线晶体学分析、电子自旋共振（ESR）、电子核双共振（ENDOR）、循环伏安法和紫外可见近红外测量。还测定了环境条件下它们在空气饱和溶液中的半衰期（tau(1/2)）。令人惊讶的是，所有三个自由基均表现出显着的稳定性：tau(1/2) = 7、3.5 和 43 天。
Organic neutral radicals have long fascinated chemists with a fundamental understanding of structurereactivity relationships in organic reactions and with applications as new functional materials. However, the elusive nature of these radicals makes the synthesis, isolation, and characterization very challenging. In this work, the synthesis of three long-lived, fluorenyl-based radicals are reported. The geometry and electronic structures of these radicals were systematically investigated with a combination of various experimental methods, besides density functional theory (DFT) calculations, which include X-ray crystallographic analysis, electron spin resonance (ESR), electron nuclear double resonance (ENDOR), cyclic voltammetry, and UVvisNIR measurements. Their half-life periods (tau(1/2)) in air-saturated solution under ambient conditions were also determined. Surprisingly, all three radicals showed remarkable stabilities: tau(1/2) = 7, 3.5, and 43 days.