Long-lived molecular anions of brominated diphenyl ethers

Abstract

Resonance electron attachment in a series of brominated diphenyl ethers, namely 4-bromodiphenyl ether (BDPE), 4-bromophenyl ether (BPE), and decabromodiphenyl ether (DBDE), was investigated in the gas phase by means of dissociative electron attachment spectroscopy. In addition to channels of dissociation into stable fragments, long-lived molecular negative ions with an average lifetime relative to autodetachment of the order of 60 µs were found for the last two molecules. In the case of BDPE and BPE, the most intense dissociation channel is the bromine anion, and for DBDE—the [C6Br5O]− anion. The [C6Br5O]− anion sequentially decomposes with the elimination of the bromide anion on a microsecond time scale, which is confirmed by the registration of metastable ions with an apparent mass of 12.8 a.m.u. The electron affinity of the studied molecules and the appearance energy of fragment ions were estimated with CAM-B3LYP/6-311+G(d,p).

Interaction of low-energy electrons with radiosensitizers

“…ref. 145–147) and may be crucial for understanding also the evolution of cyclic hydrocarbon TNIs in the solution. 57,99,148…”

Dissociative Electron Attachment to 5-Iodo-4-thio-2′-deoxyuridine: A Potential Radiosensitizer of Hypoxic Cells

“…Experimentally, we did not find any signal of the intact parent anion (mass of 370 units) within the detection limit of the apparatus. Although exceptions exist, parent anions are usually detected in mass spectrometric experiments most abundantly at the electron energy near 0 eV . A positive electron affinity (corresponding to the situation in which the ground state of the anion is energetically below that of the neutral molecule) of sufficiently high value is required for a lifetime on the order of at least microseconds, allowing detection by mass spectrometry.…”

“…Although exceptions exist, 36 parent anions are usually detected in mass spectrometric experiments most abundantly at the electron energy near 0 eV. 37 A positive electron affinity (corresponding to the situation in which the ground state of the anion is energetically below that of the neutral molecule) of sufficiently high value is required for a lifetime on the order of at least microseconds, allowing detection by mass spectrometry. The calculated adiabatic electron affinity of ISdU at the M06-2X/DGDZVP++ level is ∼1.43 eV (see Figure 2 ), which is close to that very recently reported for BrSdU (for details of the computational methods see section S.2 ).…”