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Title: Electron Affinities and Electronic Structures of o-, m-, and p- Hydroxyphenoxyl Radicals: A Combined Low-Temperature Photoelectron Spectroscopic and Ab initio Calculation Study

Abstract

Hydroxyl substituted phenoxide, o-, m-, p- HO(C6H4)O– and the corresponding neutral radicals are important species, in particularly, the p- isomer pair is directly involved in the proton-coupled electron transfer in biological photosynthetic centers. Here we report the first spectroscopic study of these species in the gas phase by means of low-temperature photoelectron spectroscopy (PES) and ab initio calculations. Vibrationally resolved PES spectra were obtained at 70 K and several photon energies for each anion, directly yielding electron affinity (EA) and electronic structure information of the corresponding hydroxyphenoxyl radical. The EAs are found to vary with OH positions, from 1.990 ± 0.010 eV (p-) to 2.315 ± 0.010 (o-) and 2.330 ± 0.010 (m-). Theoretical calculations were carried out to identify the optimized molecular structures for both anions and neutral radicals. The electron binding energies and excited state energies were also calculated to compare with experimental data. Excellent agreement is found between calculations and experiments. Molecular orbital analyses indicate strong OH anti-bonding interaction with the phenoxide moiety for o- as well as p- isomers, whereas such interaction is largely missing for the m- anion. The variance of EAs among three isomers is interpreted primarily due to the interplay between two competingmore » factors: the OH anti-bonding interaction and H-bonding stabilization (existed only in the o- anion).« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
988652
Report Number(s):
PNNL-SA-72409
25395; KC0301020; TRN: US1006703
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A, 114(34):9083-9089
Additional Journal Information:
Journal Volume: 114; Journal Issue: 34
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AFFINITY; ANIONS; ELECTRON TRANSFER; ELECTRONIC STRUCTURE; ELECTRONS; EXCITED STATES; ISOMERS; MOLECULAR STRUCTURE; PHOTOELECTRON SPECTROSCOPY; PHOTONS; RADICALS; SPECTRA; STABILIZATION; Environmental Molecular Sciences Laboratory

Citation Formats

Wang, Xue B, Fu, Qiang, and Yang, Jinlong. Electron Affinities and Electronic Structures of o-, m-, and p- Hydroxyphenoxyl Radicals: A Combined Low-Temperature Photoelectron Spectroscopic and Ab initio Calculation Study. United States: N. p., 2010. Web.
Wang, Xue B, Fu, Qiang, & Yang, Jinlong. Electron Affinities and Electronic Structures of o-, m-, and p- Hydroxyphenoxyl Radicals: A Combined Low-Temperature Photoelectron Spectroscopic and Ab initio Calculation Study. United States.
Wang, Xue B, Fu, Qiang, and Yang, Jinlong. 2010. "Electron Affinities and Electronic Structures of o-, m-, and p- Hydroxyphenoxyl Radicals: A Combined Low-Temperature Photoelectron Spectroscopic and Ab initio Calculation Study". United States.
@article{osti_988652,
title = {Electron Affinities and Electronic Structures of o-, m-, and p- Hydroxyphenoxyl Radicals: A Combined Low-Temperature Photoelectron Spectroscopic and Ab initio Calculation Study},
author = {Wang, Xue B and Fu, Qiang and Yang, Jinlong},
abstractNote = {Hydroxyl substituted phenoxide, o-, m-, p- HO(C6H4)O– and the corresponding neutral radicals are important species, in particularly, the p- isomer pair is directly involved in the proton-coupled electron transfer in biological photosynthetic centers. Here we report the first spectroscopic study of these species in the gas phase by means of low-temperature photoelectron spectroscopy (PES) and ab initio calculations. Vibrationally resolved PES spectra were obtained at 70 K and several photon energies for each anion, directly yielding electron affinity (EA) and electronic structure information of the corresponding hydroxyphenoxyl radical. The EAs are found to vary with OH positions, from 1.990 ± 0.010 eV (p-) to 2.315 ± 0.010 (o-) and 2.330 ± 0.010 (m-). Theoretical calculations were carried out to identify the optimized molecular structures for both anions and neutral radicals. The electron binding energies and excited state energies were also calculated to compare with experimental data. Excellent agreement is found between calculations and experiments. Molecular orbital analyses indicate strong OH anti-bonding interaction with the phenoxide moiety for o- as well as p- isomers, whereas such interaction is largely missing for the m- anion. The variance of EAs among three isomers is interpreted primarily due to the interplay between two competing factors: the OH anti-bonding interaction and H-bonding stabilization (existed only in the o- anion).},
doi = {},
url = {https://www.osti.gov/biblio/988652}, journal = {Journal of Physical Chemistry A, 114(34):9083-9089},
number = 34,
volume = 114,
place = {United States},
year = {Thu Sep 02 00:00:00 EDT 2010},
month = {Thu Sep 02 00:00:00 EDT 2010}
}