Electron-Induced Decomposition of Uracil-5-yl O-(N,N-dimethylsulfamate): Role of Methylation in Molecular Stability

Abstract

The incorporation of modified uracil derivatives into DNA leads to the formation of radical species that induce DNA damage. Molecules of this class have been suggested as radiosensitizers and are still under investigation. In this study, we present the results of dissociative electron attachment to uracil-5-yl O-(N,N-dimethylsulfamate) in the gas phase. We observed the formation of 10 fragment anions in the studied range of electron energies from 0–12 eV. Most of the anions were predominantly formed at the electron energy of about 0 eV. The fragmentation paths were analogous to those observed in uracil-5-yl O-sulfamate, i.e., the methylation did not affect certain bond cleavages (O-C, S-O and S-N), although relative intensities differed. The experimental results are supported by quantum chemical calculations performed at the M06-2X/aug-cc-pVTZ level of theory. Furthermore, a resonance stabilization method was used to theoretically predict the resonance positions of the fragment anions O− and CH3−.

Electron Attachment to 5-Fluorouracil: The Role of Hydrogen Fluoride in Dissociation Chemistry

“…This basis set is denoted as aug-cc-pVDZ(C,N,O,F),TZ(H)+. To estimate the position of metastable resonances, we applied the extrapolation method [ 54 ], which was described in detail in our previous work [ 55 ]. In short, we carried out the optimization of the neutral 5-FU geometry at the MP2 level [ 56 ] with the cc-pVDZ basis set [ 51 ].…”

The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years

“…We assigned 18 articles to this thematic area, namely [ 128 , 235 , 236 , 237 , 238 , 239 , 240 , 241 , 242 , 243 , 244 , 245 , 246 , 247 , 248 , 249 , 250 , 251 ]. Their distribution within the typing specified in the Introduction is presented in Table 9 .…”

“…Taking this circumstance into account, two basic variants of their systematics are possible—by the nature of the transfer (energy transfer or charge transfer) and by the physicochemical nature of the material, in which such a transfer is carried out. In the variant of systematics by the nature of transfer, all articles presented in this Thematic Area can be divided into those in which studies are related to energy transfer, and those in which studies are related to charge transfer; the first include articles [ 128 , 236 , 237 , 238 , 239 , 241 , 242 , 246 , 247 , 249 ], the second, articles [ 235 , 240 , 243 , 244 , 245 , 248 , 250 , 251 ]. In the variant of systematics by the nature of the material, two types of articles can also be distinguished—those in which the energy/charge transfer is carried out in organic materials, namely [ 128 , 236 , 237 , 238 , 240 , 243 , 244 , 247 , 249 , 250 , 251 ], and those in which this transfer is carried out in inorganic materials [ 235 , 239 , 241 , 242 , 245 , 246 , 248 ].…”

“…In the variant of systematics by the nature of transfer, all articles presented in this Thematic Area can be divided into those in which studies are related to energy transfer, and those in which studies are related to charge transfer; the first include articles [ 128 , 236 , 237 , 238 , 239 , 241 , 242 , 246 , 247 , 249 ], the second, articles [ 235 , 240 , 243 , 244 , 245 , 248 , 250 , 251 ]. In the variant of systematics by the nature of the material, two types of articles can also be distinguished—those in which the energy/charge transfer is carried out in organic materials, namely [ 128 , 236 , 237 , 238 , 240 , 243 , 244 , 247 , 249 , 250 , 251 ], and those in which this transfer is carried out in inorganic materials [ 235 , 239 , 241 , 242 , 245 , 246 , 248 ]. The second variant of the systematics of articles seems to be more expedient, which we will use as the basis for further narration about Thematic Area 8.…”

“…In [ 236 ], the discussion was about the transfer of energy; an example of an article in which the study of charge transfer took place is [ 240 ], in which the intramolecular charge transfer in a probe based on benzothiazole was recorded. These two articles, as well as [ 128 , 244 , 251 ], were devoted to organic abiogenic materials; in other articles of the “organic” profile, namely [ 237 , 238 , 243 , 247 , 249 , 250 ], materials of biological origin, very diverse in terms of their physicochemical characteristics, were used as a medium for the transfer of energy/charge—polypeptides and their derivatives [ 237 , 243 , 250 ], nitrogenase [ 247 ], and various antibiotics [ 249 ]. Among the research articles related to the above processes in inorganic materials, it should be noted that [ 241 ] was devoted to the creation of quantum dots from carbon atoms in an array of tricarbon tetranitride C 3 N 4 , and article [ 246 ] demonstrated the expediency of short-term sonoporation using microbubbles encapsulated by nanoparticles elemental gold in the treatment of liver cancer before radiation therapy.…”