Sanazole is a hypoxic radiosensitizer for which the activation mechanism in cells has been suggested to involve initial reduction. Herein, electron attachment to sanazole under isolated conditions and upon microhydrations is investigated. Employing mass spectrometry supported by quantum chemical calculations, the anion formation mechanism and subsequent fragmentation pathways are examined. In the case of electron attachment to the isolated molecule, predominantly dissociative electron attachment is observed. The most prominent fragment anion, (NTR-yl)- at m/z 113, is suggested to be formed in an exothermic pathway through a single-bond dissociation, whereas other intense fragments require structural reorganization. The limited abundance of the parent anion under isolated conditions is altered upon microhydration conditions since in the latter situation only the (microhydrated) parent anion is observed. This result suggests that hydration closes and/or slows down the dissociation process and indicates that for sanazole, the initial mechanism of action in a reductive cell environment may be similar to that of well-studied nitroimidazole radiosensitizers.

• Keywords
• electron attachment, electron‐induced dissociation, radiosensitizer, sanazol,
• MeSH
• Electrons * MeSH
• Mass Spectrometry MeSH
• Radiation-Sensitizing Agents * chemistry   MeSH
• Triazoles * chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Radiation-Sensitizing Agents * MeSH
• Triazoles * MeSH

Details of electron-induced chemistry of methyl methacrylate (MMA) upon complexation are revealed by combining gas-phase 2D electron energy loss spectroscopy with electron attachment spectroscopy of isolated MMA and its clusters. We show that even though isolated MMA does not form stable parent anions, it efficiently thermalizes the incident electrons via intramolecular vibrational redistribution, leading to autodetachment of slow electrons. This autodetachment channel is reduced in clusters due to intermolecular energy transfer and stabilization of parent molecular anions. Bond breaking via dissociative electron attachment leads to an extensive range of anion products. The dominant OCH3- channel is accessible via core-excited resonances with threshold above 5 eV, despite the estimated thermodynamic threshold below 3 eV. This changes in clusters, where MnOCH3- anions are observed in a lower-lying resonance due to neutral dissociation of the 1(n, π*) state and electron self-scavenging. The present findings have implications for electron-induced chemistry in lithography with poly(methyl methacrylate).

• Publication type
• Journal Article MeSH