Maitra Anwesha, Lake William R, Mohamed Ahmed, Edington Sean C, Das Pratyusha, Thompson Barry C, Hammes-Schiffer Sharon, Johnson Mark, Dawlaty Jahan M
Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
J Phys Chem Lett. 2024 Jul 25;15(29):7458-7465. doi: 10.1021/acs.jpclett.4c01303. Epub 2024 Jul 15.
Controlling reactivity with electric fields is a persistent challenge in chemistry. One approach is to tether ions at well-defined locations near a reactive center. To quantify fields arising from ions, we report crown ethers that capture metal cations as field sources and a covalently bound vibrational Stark shift probe as a field sensor. We use experiments and computations in both the gas and liquid phases to quantify the vibrational frequencies of the probe and estimate the electric fields from the captured ions. Cations, in general, blue shift the probe frequency, with effective fields estimated to vary in the range of ∼0.2-3 V/nm in the liquid phase. Comparison of the gas and liquid phase data provides insight into the effects of mutual polarization of the molecule and solvent and screening of the ion's field. These findings reveal the roles of charge, local screening, and geometry in the design of tailored electric fields.
利用电场控制反应活性是化学领域长期存在的挑战。一种方法是将离子束缚在反应中心附近定义明确的位置。为了量化离子产生的电场，我们报道了将金属阳离子捕获为场源的冠醚以及作为场传感器的共价结合的振动斯塔克位移探针。我们在气相和液相中进行实验和计算，以量化探针的振动频率，并估计捕获离子产生的电场。一般来说，阳离子会使探针频率发生蓝移，液相中的有效电场估计在~0.2 - 3 V/nm范围内变化。气相和液相数据的比较有助于深入了解分子与溶剂的相互极化以及离子场屏蔽的影响。这些发现揭示了电荷、局部屏蔽和几何结构在定制电场设计中的作用。
