Modeling deoxyribose radicals by neutralization-reionization mass spectrometry. Part 2. Preparation,dissociations, and energetics of 3-hydroxyoxolan-3-yl radical and cation |
| |
Authors: | Shetty?Vivekananda,Martin?Sadílek,Xiaohong?Chen,Luke?E.?Adams,Franti?ek?Ture?ek author-information" > author-information__contact u-icon-before" > mailto:turecek@chem.washington.edu" title=" turecek@chem.washington.edu" itemprop=" email" data-track=" click" data-track-action=" Email author" data-track-label=" " >Email author |
| |
Affiliation: | Department of Chemistry, University of Washington, Seattle, 98195, USA. |
| |
Abstract: | The title radical (1) is generated in the gas-phase by collisional neutralization of carbonyl-protonated oxolan-3-one. A 1.5% fraction of 1 does not dissociate and is detected following reionization as survivor ions. The major dissociation of 1 (approximately 56%) occurs as loss of the hydroxyl H atom forming oxolan-3-one (2). The competing ring cleavages by O[bond]C-2 and C-4[bond]C-5 bond dissociations combined account for approximately 42% of dissociation and result in the formation of formaldehyde and 2-hydroxyallyl radical. Additional ring-cleavage dissociations of 1 resulting in the formation of C(2)H(3)O and C(2)H(4)O cannot be explained as occurring competitively on the doublet ground (X) electronic state of 1, but are energetically accessible from the A and higher electronic states accessed by vertical electron transfer. Exothermic protonation of 2 also produces 3-oxo-(1H)-oxolanium cation (3(+)) which upon collisional neutralization gives hypervalent 3-oxo-(1H)-oxolanium radical (3). The latter dissociates spontaneously by ring opening and expulsion of hydroxy radical. Experiment and calculations suggest that carbohydrate radicals incorporating the 3-hydroxyoxolan-3-yl motif will prefer ring-cleavage dissociations at low internal energies or upon photoexcitation by absorbing light at approximately 590 and approximately 400 nm. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|