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A Photochemically Generated Selenyl Free Radical Observed by High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy

Nehzati, Susan LU ; Dolgova, Natalia V. ; Sokaras, Dimosthenis ; Kroll, Thomas ; Cotelesage, Julien J.H. ; Pickering, Ingrid J. and George, Graham N. (2018) In Inorganic Chemistry 57(17). p.10867-10872
Abstract

Selenium-based selenyl free radicals are chemical entities that may be involved in a range of biochemical processes. We report the first X-ray spectroscopic observation of a selenyl radical species generated photochemically by X-ray irradiation of low-temperature solutions of l-selenocysteine. We have employed high energy resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS) and electron paramagnetic resonance (EPR) spectroscopy, coupled with density functional theory calculations, to characterize and understand the species. The HERFD-XAS spectrum of the selenyl radical is distinguished by a uniquely low-energy transition with a peak energy at 12659.0 eV, which corresponds to a 1s → 4p transition to the singly... (More)

Selenium-based selenyl free radicals are chemical entities that may be involved in a range of biochemical processes. We report the first X-ray spectroscopic observation of a selenyl radical species generated photochemically by X-ray irradiation of low-temperature solutions of l-selenocysteine. We have employed high energy resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS) and electron paramagnetic resonance (EPR) spectroscopy, coupled with density functional theory calculations, to characterize and understand the species. The HERFD-XAS spectrum of the selenyl radical is distinguished by a uniquely low-energy transition with a peak energy at 12659.0 eV, which corresponds to a 1s → 4p transition to the singly occupied molecular orbital of the free radical. The EPR spectrum shows the broad features and highly anisotropic g-values that are expected for a selenium free radical species. The availability of spectroscopic probes for selenyl radicals may assist in understanding why life chooses selenium over sulfur in selected biochemical processes.

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author
; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
in
Inorganic Chemistry
volume
57
issue
17
pages
6 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85053029738
ISSN
0020-1669
DOI
10.1021/acs.inorgchem.8b01522
language
English
LU publication?
no
id
1ed0d975-b39e-4592-8915-f399f6851412
date added to LUP
2020-01-30 12:57:01
date last changed
2022-04-10 23:51:51
@article{1ed0d975-b39e-4592-8915-f399f6851412,
  abstract     = {{<p>Selenium-based selenyl free radicals are chemical entities that may be involved in a range of biochemical processes. We report the first X-ray spectroscopic observation of a selenyl radical species generated photochemically by X-ray irradiation of low-temperature solutions of l-selenocysteine. We have employed high energy resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS) and electron paramagnetic resonance (EPR) spectroscopy, coupled with density functional theory calculations, to characterize and understand the species. The HERFD-XAS spectrum of the selenyl radical is distinguished by a uniquely low-energy transition with a peak energy at 12659.0 eV, which corresponds to a 1s → 4p transition to the singly occupied molecular orbital of the free radical. The EPR spectrum shows the broad features and highly anisotropic g-values that are expected for a selenium free radical species. The availability of spectroscopic probes for selenyl radicals may assist in understanding why life chooses selenium over sulfur in selected biochemical processes.</p>}},
  author       = {{Nehzati, Susan and Dolgova, Natalia V. and Sokaras, Dimosthenis and Kroll, Thomas and Cotelesage, Julien J.H. and Pickering, Ingrid J. and George, Graham N.}},
  issn         = {{0020-1669}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{17}},
  pages        = {{10867--10872}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Inorganic Chemistry}},
  title        = {{A Photochemically Generated Selenyl Free Radical Observed by High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy}},
  url          = {{http://dx.doi.org/10.1021/acs.inorgchem.8b01522}},
  doi          = {{10.1021/acs.inorgchem.8b01522}},
  volume       = {{57}},
  year         = {{2018}},
}