The mechanochemical production of phenyl cations through heterolytic bond scission.
The mechanochemical production of phenyl cations through heterolytic bond scission.
复制标题
通过异解键断裂机械化学生产苯基阳离子。
作者：
T. Shiraki;C. Diesendruck;Jeffrey S. Moore
施加到聚合物材料上的高机械力通常会引起非选择性断链。在过去的十年中，机械响应分子（机械载体）被设计用于利用施加到聚合物上的机械能并提供有效的化学反应。通过将过氧化物和偶氮机械基团掺入聚合物主链中，实现了化学键的选择性均裂。然而，聚合物机械化学中的选择性异质分解仍然大多尚未实现。我们假设离子物种中的高度极化键可能会发生异裂键断裂。为了测试这一点，我们检查了三芳基锍盐（TAS）作为机械载体。通过单电子转移活性自由基聚合（SET-LRP）方法合成了链中心具有TAS的聚丙烯酸甲酯（PMA-TAS）。溶液中的计算和实验研究揭示了 PMA-TAS 中苯基阳离子的机械化学生产。有趣的是，生成的苯基阳离子与其反阴离子（三氟甲磺酸盐）反应生成末端三氟甲基苯结构，据我们所知，在 TAS 光解中未观察到该结构。此外，可以通过添加亲核试剂来捕获苯基阳离子。这些发现强调了通过机械激活可用的有趣反应途径。
High mechanical forces applied to polymeric materials typically induce unselective chain scission. For the last decade, mechanoresponsive molecules, mechanophores, have been designed to harness the mechanical energy applied to polymers and provide a productive chemical response. The selective homolysis of chemical bonds was achieved by incorporating peroxide and azo mechanophores into polymer backbones. However, selective heterolysis in polymer mechanochemistry is still mostly unachieved. We hypothesized that highly polarized bonds in ionic species are likely to undergo heterolytic bond scission. To test this, we examined a triarylsulfonium salt (TAS) as a mechanophore. Poly(methyl acrylate) possessing TAS at the center of the chain (PMA-TAS) is synthesized by a single electron transfer living radical polymerization (SET-LRP) method. Computational and experimental studies in solution reveal the mechanochemical production of phenyl cations from PMA-TAS. Interestingly, the generated phenyl cation reacts with its counter-anion (trifluoromethanesulfonate) to produce a terminal trifluoromethyl benzene structure that, to the best of our knowledge, is not observed in the photolysis of TAS. Moreover, the phenyl cation can be trapped by the addition of a nucleophile. These findings emphasize the interesting reaction pathways that become available by mechanical activation.
影响因子：
15
作者：
Kean ZS;Niu Z;Hewage GB;Rheingold AL;Craig SL
通讯作者：
Craig SL