Electron-Induced Dissociation of the Potential Radiosensitizer 5-Selenocyanato-2′-deoxyuridine

• DOI: 10.1021/acs.jpcb.8b11523
• Publication Date: 2019-01-18T21:36:52Z
• Authors: Rebecca Meißner; Samanta Makurat; Witold Kozak; Paulo Limão-Vieira; Janusz Rak; Stephan Denifl
• Keywords: Fragmentation; Radiosensitizer

5-Selenocyanato-2'-deoxyuridine (SeCNdU) is a recently proposed radiosensitizer based on 2'-deoxyuridine (dU) with the electron-affinic selenocyanato (-SeCN) side group attached at C5 position of uracil. Since electron interaction processes may be an important source DNA damage by ionizing radiation, we have studied low-energy dissociative attachment to SeCNdU in gas phase. Negative ion formation has been obtained means mass spectrometry, where rich fragmentation pattern observed even ∼0 eV. The reaction pathways exhibiting highest yields are C4N2O2H2Se•- and CN-, both involving cleavage Se-CN bond. heaviest fragment anion C9N2O5H10Se•-, besides charged species, hydrogen cyano radicals also formed. Further decomposition channels yield highly reactive hydroxyl radical, which possesses high potential. All experimentally determined onsets 0 eV, supported calculations performed M06-2X/aug-cc-pVTZ level. comprise thermochemical thresholds standard experimental (428.15 K, 3 × 10-11 atm) conditions together adiabatic affinities. present study shows that electrons very effectively decompose upon thermal electrons, producing large variety fragments radicals.