Heavy element incorporation in nitroimidazole radiosensitizers: molecular-level insights into fragmentation dynamics

Abstract

The present study investigates the photofragmentation behavior of iodine-enhanced nitroimidazole-based radiosensitizer model compounds in their protonated form using near-edge X-ray absorption mass spectrometry and quantum mechanical calculations.

Shell-dependent photofragmentation dynamics of a heavy-atom-containing bifunctional nitroimidazole radiosensitizer

“…Previous molecular studies have aimed to provide a fundamental understanding of the activation by probing the interactions between radiosensitizers and ionizing radiation/secondary particles (ions, electrons) in the gas phase. 9–23 These fragmentation-oriented studies provided valuable insight into the occurring rearrangement reactions and the fragment formation upon dissociation of various nitroimidazole-based radiosensitizers – predominantly in the photon energy region ≈60–670 eV. Notably, the efficiency of the radiosensitizers was suggested to be correlated with the quantity of produced ions/radicals originating from the nitro group.…”

“…The molecule combines two distinct sensitization mechanisms characteristic of both heavy elements and nitroimidazoles. The fragmentation of the protonated version of this molecule was recently studied using near-edge X-ray absorption mass spectrometry, 23 and building on this we examine here the fragmentation behavior of the non-protonated molecule upon core-ionization at the I 4d, Br 3d, and I 3d edges using multiparticle coincidence spectroscopy in the gas phase and Born–Oppenheimer-based molecular dynamics. The primary objective is to quantify the resulting fragments and their kinetic energies aiming to find clues regarding the better radiosensitivity of halogenated nitroimidazoles from the perspective of molecular fragmentation.…”