放射增敏剂尼莫唑及相关化合物的光电子能谱和电子结构

Photoelectron Spectra and Electronic Structures of the Radiosensitizer Nimorazole and Related Compounds.

作者信息

Feketeová Linda, Plekan Oksana, Goonewardane Mayanthi, Ahmed Marawan, Albright Abigail L, White Jonathan, O'Hair Richard A J, Horsman Michael R, Wang Feng, Prince Kevin C

机构信息

School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne , 30 Flemington Road, 3010 Parkville, Victoria, Australia.

ARC Centre of Excellence for Free Radical Chemistry and Biotechnology , Parkville, Victoria 3010, Australia.

出版信息

J Phys Chem A. 2015 Oct 1;119(39):9986-95. doi: 10.1021/acs.jpca.5b05950. Epub 2015 Sep 18.

DOI:10.1021/acs.jpca.5b05950

PMID:26344652

Abstract

Soft X-ray photoelectron spectroscopy has been used to investigate the radiosensitizer nimorazole and related model compounds. We report the valence and C, N, and O 1s photoemission spectra and K-edge NEXAFS spectra of gas-phase nimorazole, 1-methyl-5-nitroimidazole, and 4(5)-nitroimidazole in combination with theoretical calculations. The valence band and core level spectra are in agreement with theory. We determine the equilibrium populations of the two tautomers in 4(5)-nitroimidazole and find a ratio of 1:0.7 at 390 K. The NEXAFS spectra of the studied nitroimidazoles show excellent agreement with spectra of compounds available in the literature that exhibit a similar chemical environment. By comparing 1-methyl-5-nitroimidazole (single tautomer) with 4(5)-nitroimidazole, we are able to disentangle the photoemission and photoabsorption spectra and identify features due to each single tautomer.

摘要

软X射线光电子能谱已被用于研究放射增敏剂尼莫唑及相关模型化合物。我们报告了气相尼莫唑、1-甲基-5-硝基咪唑和4(5)-硝基咪唑的价带以及C、N和O 1s光电子能谱和K边近边X射线吸收精细结构光谱，并结合理论计算。价带和芯能级光谱与理论相符。我们确定了4(5)-硝基咪唑中两种互变异构体的平衡丰度，发现在390 K时比例为1:0.7。所研究的硝基咪唑的近边X射线吸收精细结构光谱与文献中具有相似化学环境的化合物光谱显示出极好的一致性。通过比较1-甲基-5-硝基咪唑（单一互变异构体）和4(5)-硝基咪唑，我们能够解析光电子能谱和光吸收光谱，并识别出每种单一互变异构体的特征。