2,6-di-tert-butyl-4-(4′-nitrophenyl)phenoxyl radical | 139428-53-8

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 英文名称: 2,6-di-tert-butyl-4-(4′-nitrophenyl)phenoxyl radical
• CAS: 139428-53-8
• 化学式: C₂₀H₂₄NO₃
• 分子量: 326.415
• InChiKey: GMOLDUBGOWUIDD-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  6.4
• 重原子数：
  24
• 可旋转键数：
  3
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.4
• 拓扑面积：
  46.8
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  2,6-di-tert-butyl-4-(4′-nitrophenyl)phenoxyl radical 在 2,4,6-三叔丁基苯酚 作用下， 以 甲苯 为溶剂， 生成 4-(4'-nitrophenyl)-2,6-di-tert-butylphenol
  参考文献：
  名称：

  可分离 4-芳基苯氧基自由基的制备、结构表征和热化学

  摘要：

  描述了4-(硝基苯基)苯氧基自由基、2,6-二叔丁基-4-(4'-硝基苯基)苯氧基自由基( t Bu 2 NPArO • )的制备和完整表征。这是可分离且具有晶体学特征的苯氧基的罕见例子，也是唯一一个在晶体学上也明确定义了母体苯酚的例子。EPR 光谱分析表明仲芳环和硝基上有一些自旋离域。平衡研究表明，相应的苯酚在 MeCN 中的O-H 键解离自由能 (BDFE) 为 77.8 ± 0.5 kcal mol –1 （在甲苯中为 77.5 ± 0.5 kcal mol –1）。该值高于相关的分离苯氧基自由基，使其成为氢原子转移 (HAT) 研究的有用试剂。还讨论了其他热化学和光谱参数。

  DOI：

  10.1021/jo501531a
• 作为产物：
  描述：

  4-(4'-nitrophenyl)-2,6-di-tert-butylphenol 在 sodium hydroxide 、 potassium hexacyanoferrate(III) 作用下， 以 苯 为溶剂， 反应 1.0h， 以52%的产率得到2,6-di-tert-butyl-4-(4′-nitrophenyl)phenoxyl radical
  参考文献：
  名称：

  可分离 4-芳基苯氧基自由基的制备、结构表征和热化学

  摘要：

  描述了4-(硝基苯基)苯氧基自由基、2,6-二叔丁基-4-(4'-硝基苯基)苯氧基自由基( t Bu 2 NPArO • )的制备和完整表征。这是可分离且具有晶体学特征的苯氧基的罕见例子，也是唯一一个在晶体学上也明确定义了母体苯酚的例子。EPR 光谱分析表明仲芳环和硝基上有一些自旋离域。平衡研究表明，相应的苯酚在 MeCN 中的O-H 键解离自由能 (BDFE) 为 77.8 ± 0.5 kcal mol –1 （在甲苯中为 77.5 ± 0.5 kcal mol –1）。该值高于相关的分离苯氧基自由基，使其成为氢原子转移 (HAT) 研究的有用试剂。还讨论了其他热化学和光谱参数。

  DOI：

  10.1021/jo501531a

文献信息

• Protonation of a Cobalt Phenylazopyridine Complex at the Ligand Yields a Proton, Hydride, and Hydrogen Atom Transfer Reagent
  作者：Elizabeth A. McLoughlin、Kate M. Waldie、Srinivasan Ramakrishnan、Robert M. Waymouth

  DOI：10.1021/jacs.8b06156

  日期：2018.10.17

  Protonation of the Co(I) phenylazopyridine (azpy) complex [CpCo(azpy)] 2 occurs at the azo nitrogen of the 2-phenylazopyridine ligand to generate the cationic Co(I) complex [CpCo(azpyH)]+ 3 with no change in oxidation state at Co. The N-H bond of 3 exhibits diverse hydrogen transfer reactivity, as studies with a variety of organic acceptors demonstrate that 3 can act as a proton, hydrogen atom, and

  Co(I) 苯基偶氮吡啶 (azpy) 复合物 [CpCo(azpy)] 2 的质子化发生在 2-苯基偶氮吡啶配体的偶氮氮上，生成阳离子 Co(I) 复合物 [CpCo(azpyH)]+ 3，没有变化在 Co 处处于氧化态。 3 的 NH 键表现出不同的氢转移反应性，因为对各种有机受体的研究表明 3 可以充当质子、氢原子和氢化物供体。NH 键的所有三种裂解模式（即质子、氢化物和氢原子）的热力学都通过实验和计算进行了检查。3 的 NH 键在 CD3CN 中表现出 ap Ka 为 12.1，氢度为 Δ G°H- = 89 kcal/mol，键解离自由能 (BDFE) 为 Δ G°H• = 68 kcal/mol。氢化物从 3 转移到三苯甲基阳离子 (Δ G°H- = 99 kcal/mol) 需要几个小时才能完成，这表明 3 在动力学和热力学上都是相对较差的氢化物供体。氢原子从 3 到 2,6
• Mechanism of antioxidant reaction of vitamin E: charge transfer and tunneling effect in proton-transfer reaction
  作者：Shinichi Nagaoka、Aya Kuranaka、Hideki Tsuboi、Umpei Nagashima、Kazuo Mukai

  DOI：10.1021/j100185a065

  日期：1992.3

  In order to shed light on the mechanism of proton-transfer reactions, a kinetic and ab initio study of the antioxidant action (intermolecular proton transfer) of vitamin E derivatives has been carried out. The second-order rate constants (k(s)'s) for the reaction of tocopherols (TocH's) with variously substituted phenoxyl radicals (PhO.'s) in ethanol were measured with a stopped-flow spectrophotometer. The half-wave reduction potentials (E1/2's) of PhO.'s were obtained by using a cyclic voltammetry technique. The result indicates that k(s) increases as the total electron-donating capacity of the alkyl substituents at the aromatic ring of TocH or the electron-withdrawing capacity of the substituent of PhO. increases. k(s) for the reaction of deuterated tocopherol derivatives (TocD's) with a PhO. in deuterated ethanol (C2H5OD, ethanol-d1) was also measured. A substantial deuterium kinetic isotope effect on k(s) is observed. In the reactions of each PhO. with various TocH's, a plot of log k(s) vs peak oxidation potential (E(p)) of TocH is found to be linear. The slope of its plot for TocD's is clsoe to that for TocH's. In the reactions of each TocH with various PhO.'s, a plot of log k(s) vs E1/2 of PhO. is found to be linear. The geometries of TocH's were optimized with the semiempirical modified neglect of diatomic overlap (MNDO) method. The Koopmans' theorem first ionization energies (IP) for those geometries were calculated with the ab initio method. In the reactions of a PhO. with various TocH's, plots of log k(s) vs IP, the activation energy (E(act)) vs IP, and E(p) vs IP are also found to be linear. From these results, it is considered that both the charge transfer and the proton tunneling play important roles in the antioxidant reaction of TocH. The transition state has the property of the charge-transfer species. The proton tunneling takes place below the transition state. Tunneling allows the proton to cut a corner on the potential energy surface. Our explanation will be widely applicable to many proton-transfer reactions.