Vibrational Strong Coupling (VSC) has been reported to change the rate of organic reactions. However, a lack of convenient and reliable methods to measure reaction kinetics under VSC makes it challenging to obtain mechanistic insight into its influence, hindering progress in the field. Here, we use recently developed fixed‐width optical cavities to obtain large kinetic datasets under VSC with small errors (± 1‐5%) in an operationally simple manner using UV‐vis spectroscopy. The setup is used to test whether VSC changes a fundamental kinetic property of polar reactions, nucleophilicity, for water and alcohols, species commonly used in VSC‐modified chemistry. We determined the rate constants for nucleophilic capture with a library of benzhydrilium ions as reference electrophiles with and without strong coupling of the nucleophile’s key vibrations. For all investigated combinations of electrophiles and nucleophiles, only minor changes in the observed rate constants of the reactions were observed, independently of the coupled bands. These results indicate that VSC does not substantially alter the nucleophilicity of water and alcohols, suggesting that polar reactions are modified through other, presently unknown mechanisms. Fixed‐width cavities allow for convenient and reproducible UV‐vis kinetics, facilitating mechanistic studies of VSC‐modified chemistry.

中文翻译：

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测量振动强耦合下的动力学：测试水和醇的亲核性变化


据报道，振动强耦合（VSC）可以改变有机反应的速率。然而，由于缺乏方便可靠的方法来测量 VSC 下的反应动力学，因此很难深入了解其影响的机理，从而阻碍了该领域的进展。在这里，我们使用最近开发的固定宽度光学腔，使用紫外-可见光谱以操作简单的方式获得 VSC 下的大动力学数据集，误差小 (± 1-5%)。该装置用于测试 VSC 是否改变了水和醇（VSC 改性化学中常用的物质）极性反应的基本动力学特性，即亲核性。我们确定了使用二苯甲基鎓离子库作为参考亲电子试剂的亲核捕获的速率常数，有和没有亲核试剂关键振动的强耦合。对于所有研究的亲电子试剂和亲核试剂的组合，仅观察到观察到的反应速率常数的微小变化，与耦合带无关。这些结果表明 VSC 不会显着改变水和醇的亲核性，表明极性反应是通过其他目前未知的机制进行修改的。固定宽度的腔体可实现方便且可重复的紫外-可见动力学，促进 VSC 改性化学的机理研究。