Hsu Tzu-Yao, Berthin Roxanne, Serva Alessandra, Reeves Kyle, Salanne Mathieu, Jeanmairet Guillaume
Sorbonne Université, CNRS, Physico-Chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France.
Maison de la Simulation, CEA, CNRS, Univ. Paris-Sud, UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France.
J Chem Phys. 2022 Sep 7;157(9):094103. doi: 10.1063/5.0102238.
Quinones are redox active organic molecules that have been proposed as an alternative choice to metal-based materials in electrochemical energy storage devices. Functionalization allows one to fine tune not only their chemical stability but also the redox potential and kinetics of the electron transfer reaction. However, the reaction rate constant is not only determined by the redox species but also impacted by solvent effects. In this work, we show how the functionalization of benzoquinone with different functional groups impacts the solvent reorganization free energies of electron transfer half-reactions in acetonitrile. The use of molecular density functional theory, whose computational cost for studying the electron transfer reaction is considerably reduced compared to the state-of-the-art molecular dynamics simulations, enables us to perform a systematic study. We validate the method by comparing the predictions of the solvation shell structure and the free energy profiles for electron transfer reaction to the reference classical molecular dynamics simulations in the case of anthraquinone solvated in acetonitrile. We show that all the studied electron transfer half-reactions follow the Marcus theory, regardless of functional groups. Consequently, the solvent reorganization free energy decreases as the molecular size increases.
醌类是具有氧化还原活性的有机分子，已被提议作为电化学储能装置中金属基材料的替代选择。功能化不仅可以微调它们的化学稳定性，还可以调节氧化还原电位和电子转移反应的动力学。然而，反应速率常数不仅由氧化还原物种决定，还受溶剂效应的影响。在这项工作中，我们展示了用不同官能团对苯醌进行功能化如何影响乙腈中电子转移半反应的溶剂重组自由能。与最先进的分子动力学模拟相比，分子密度泛函理论研究电子转移反应的计算成本大大降低，这使我们能够进行系统的研究。在蒽醌溶解于乙腈的情况下，我们通过将溶剂化壳层结构的预测和电子转移反应的自由能分布与参考经典分子动力学模拟进行比较来验证该方法。我们表明，所有研究的电子转移半反应都遵循Marcus理论，与官能团无关。因此，溶剂重组自由能随着分子尺寸的增加而降低。
