How does methylation suppress the electron-induced decomposition of 1-methyl-nitroimidazoles?

Autor(es)

Kossoski, F. ^{[1, 2]} ; Varella, M. T. do N. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

^[2] Aix Marseille Univ, CNRS, ICR, Marseille - France

^[3] Univ Sao Paulo, Inst Fis, Rua Matao 1731, BR-05508090 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Chemical Physics; v. 147, n. 16 OCT 28 2017.
• Citações Web of Science: 4

Resumo

The efficient decomposition of nitroimidazoles (NIs) by low energy electrons is believed to underlie their radiosensitizing properties. Recent dissociative electron attachment (DEA) measurements showed that methylation at the N1 site unexpectedly suppresses the electron-induced reactions in 4(5)-NI. We report theoretical results that provide a clear interpretation of that astounding finding. Around 1.5 eV, DEA reactions into several fragments are initiated by a pi{*} resonance, not considered in previous studies. The autoionization lifetime of this anion state, which limits the predissociation dynamics, is considerably shorter in the methylated species, thereby suppressing the DEA signals. On the other hand, the lifetime of the pi{*} resonance located around 3 eV is less affected by methylation, which explains why DEA is still observed at these energies. Our results demonstrate how even a simple methylation can significantly modify the probabilities for DEA reactions, which may be significant for NI-based cancer therapy. Published by AIP Publishing. (AU)

• Processo FAPESP: 14/10012-9 - Transientes moleculares
• Beneficiário: Márcio Teixeira do Nascimento Varella
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 15/23792-5 - Dinâmica semiclássica não-adiabática de ânions transientes
• Beneficiário: Fábris Kossoski
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado