Journal article

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

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

The Journal of Physical Chemistry A | AMER CHEMICAL SOC | Published : 2015

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 environmen..

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Funding Acknowledgements

The authors gratefully acknowledge support by the staff of Elettra-Sincrotrone Trieste for providing high quality light and for technical assistance on the Gas Phase beamline. We thank the ARC for support via the award of an APD (to L.F.) and through the CoE program. We thank the Department of Experimental Clinical Oncology, Aarhus University Hospital for the sample of nimorazole. M.G. was an undergraduate honours student who thanks the Swinburn University for the opportunity to work on this project. M.A. acknowledges the Swinburne University Postgraduate Research Award (SUPRA). F.W. thanks Swinburne University supercomputing (Green/gSTAR) for support on the computing facilities and the Victorian Life Sciences Computation Initiative (VLSCI) on its Peak Computing Facility at the University of Melbourne.