Department of Chemistry and Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavik, Iceland.
Int J Mol Sci. 2022 Feb 23;23(5):2430. doi: 10.3390/ijms23052430.
In chemoradiation therapy, dissociative electron attachment (DEA) may play an important role with respect to the efficiency of the radiosensitizers used. The rational tailoring of such radiosensitizers to be more susceptive to DEA may thus offer a path to increase their efficiency. Potentially, this may be achieved by tailoring rearrangement reactions into the DEA process such that these may proceed at low incident electron energies, where DEA is most effective. Favorably altering the orbital structure of the respective molecules through substitution is another path that may be taken to promote dissociation up on electron capture. Here we present a combined experimental and theoretical study on DEA in relation to pentafluorothiophenol (PFTP) and 2-fluorothiophenol (2-FTP). We investigate the thermochemistry and dynamics of neutral HF formation through DEA as means to lower the threshold for dissociation up on electron capture to these compounds, and we explore the influence of perfluorination on their orbital structure. Fragment ion yield curves are presented, and the thermochemical thresholds for the respective DEA processes are computed as well as the minimum energy paths for HF formation up on electron capture and the underlying orbital structure of the respective molecular anions. We show that perfluorination of the aromatic ring in these compounds plays an important role in enabling HF formation by further lowering the threshold for this process and through favorable influence on the orbital structure, such that DEA is promoted. We argue that this approach may offer a path for tailoring new and efficient radiosensitizers.
在化学放射治疗中，电子离解（DEA）可能在所用放射增敏剂的效率方面发挥重要作用。因此，对这些放射增敏剂进行合理的调整，使其更容易受到 DEA 的影响，可能是提高其效率的一种途径。通过将重排反应纳入 DEA 过程中，从而使这些反应可以在 DEA 最有效的低入射电子能量下进行，可能会实现这一目标。通过取代来有利地改变各分子的轨道结构，也是促进电子俘获后解离的另一种途径。在这里，我们提出了一个关于五氟硫酚（PFTP）和 2-氟硫酚（2-FTP）的 DEA 的实验和理论综合研究。我们研究了通过 DEA 形成中性 HF 的热化学和动力学，以此降低这些化合物电子俘获后解离的阈值，并探讨了全氟化对其轨道结构的影响。我们提出了碎片离子产率曲线，并计算了相应的 DEA 过程的热化学阈值，以及电子俘获后 HF 形成的最低能量路径以及各分子阴离子的轨道结构。我们表明，这些化合物中芳环的全氟化在通过进一步降低该过程的阈值和通过对轨道结构的有利影响来促进 HF 形成方面发挥了重要作用。我们认为，这种方法可能为设计新型高效放射增敏剂提供一种途径。
