Long-lived molecular anions of brominated diphenyl ethers.

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).