Nitroimidazoles are a class of chemicals with a remarkable broad spectrum of applications from the production of explosives to the use as radiosensitizers in radiotherapy. The understanding of thedynamics of their fragmentation induced by ionizing sources is of fundamental interest. The goal of this work is to theoretically investigate the kinetic competition between the two most important decomposition channels of 2, 4 and 5-Nitroimidazole cations: the NO and NO2 losses. The calculated rate constants of the two processes are in very good agreement with the experimental Photoelectron-Photoion Coincidence (PEPICO) branching ratio. This study solves the intriguing and theoretically unexplained experimental observation that 2-Nitroimidazole, at variance with the other two regio-isomers is a source for only NO at low energies (<12.76 eV). This is a key point for biomedical application of the nitroimidazoles, because NO is the vasodilator that favors the reoxigenation of hypoxic tumor tissues.

Ionization of 2-and 4(5)-Nitroimidazoles Radiosensitizers: a "Kinetic Competition" Between NO2 and NO Losses

Satta Mauro;Casavola Anna Rita;Cartoni Antonella;Castrovilli Mattea Carmen;Catone Daniele;Chiarinelli Jacopo;Borocci Stefano;Avaldi Lorenzo;Bolognesi Paola
2021

Abstract

Nitroimidazoles are a class of chemicals with a remarkable broad spectrum of applications from the production of explosives to the use as radiosensitizers in radiotherapy. The understanding of thedynamics of their fragmentation induced by ionizing sources is of fundamental interest. The goal of this work is to theoretically investigate the kinetic competition between the two most important decomposition channels of 2, 4 and 5-Nitroimidazole cations: the NO and NO2 losses. The calculated rate constants of the two processes are in very good agreement with the experimental Photoelectron-Photoion Coincidence (PEPICO) branching ratio. This study solves the intriguing and theoretically unexplained experimental observation that 2-Nitroimidazole, at variance with the other two regio-isomers is a source for only NO at low energies (<12.76 eV). This is a key point for biomedical application of the nitroimidazoles, because NO is the vasodilator that favors the reoxigenation of hypoxic tumor tissues.
2021
Istituto di Struttura della Materia - ISM - Sede Secondaria Montelibretti
Istituto di Struttura della Materia - ISM - Sede Roma Tor Vergata
Istituto per i Sistemi Biologici - ISB (ex IMC)
rate coefficient, radiotherapy, high-energy density materials, variational transition state theory, density functional calculations
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/440955
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