Sedmidubská Barbora, Denisov Sergey, Mostafavi Mehran, Denifl Stephan, Izadi Fahrad, Ončák Milan, Luxford Thomas F M, Chvátil David, Pinkas Jiří, Kočišek Jaroslav
J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, Prague, 182223, Czech Republic.
Institut de Chimie Physique UMR 8000, CNRS/Université Paris-Saclay, Bâtiment 349, Orsay, 91405, France.
Chemistry. 2025 Jun 3;31(31):e202500859. doi: 10.1002/chem.202500859. Epub 2025 May 9.
Reactivity toward low-energy electrons (LEE) has been hypothesized as a cause of radio-modifying properties for various molecules. LEE's transient nature, however, prevents the establishment of clear links between initial processes at the sub-ps time scale and the final products of radiolysis. Here, such links are explored for the radio-modifying compound RRx-001 (1-bromoacetyl-3,3-dinitroazetidine). Picosecond pulse radiolysis demonstrates the high scavenging capacity of the molecule for secondary quasi-free and solvated electrons forming stable parent anions confirmed by studies of microsolvated RRx-001 in clusters. The anions decay either via auto-detachment of an electron or dissociate involving hydrogen transfer from solvent, resulting in NO and 1-(bromoacetyl)-3-nitroazetidine. Surprisingly, no Br dissociation is observed despite its high electron affinity. We assign this behavior to the "inaccessibility" of sigma virtual states for electrons in the solvent, which can be of a general nature.
低能电子（LEE）的反应性被认为是各种分子具有辐射修饰特性的一个原因。然而，LEE的瞬态性质使得在亚皮秒时间尺度上的初始过程与辐射分解的最终产物之间难以建立明确的联系。在此，我们对辐射修饰化合物RRx-001（1-溴乙酰基-3,3-二硝基氮杂环丁烷）进行了此类联系的探索。皮秒脉冲辐解表明，该分子对次级准自由电子和溶剂化电子具有高清除能力，形成稳定的母体阴离子，这一点在对团簇中微溶剂化RRx-001的研究中得到了证实。阴离子通过电子的自脱离或涉及溶剂氢转移的解离而衰变，生成NO和1-（溴乙酰基）-3-硝基氮杂环丁烷。令人惊讶的是，尽管溴具有高电子亲和力，但未观察到溴的解离。我们将这种行为归因于溶剂中电子对σ虚态的“不可接近性”，这可能具有普遍性质。
