Electron Transfer Induced Decomposition in Potassium-Nitroimidazoles Collisions: An Experimental and Theoretical Work.

Mónica Mendes,Marie-Christine Bacchus-Montabonel,Paulo Limão-Vieira,Gustavo García

doi:10.3390/ijms20246170

Abstract

Electron transfer induced decomposition mechanism of nitroimidazole and a selection of analogue molecules in collisions with neutral potassium (K) atoms from 10 to 1000 eV have been thoroughly investigated. In this laboratory collision regime, the formation of negative ions was time-of-flight mass analyzed and the fragmentation patterns and branching ratios have been obtained. The most abundant anions have been assigned to the parent molecule and the nitrogen oxide anion (NO2–) and the electron transfer mechanisms are comprehensively discussed. This work focuses on the analysis of all fragment anions produced and it is complementary of our recent work on selective hydrogen loss from the transient negative ions produced in these collisions. Ab initio theoretical calculations were performed for 4-nitroimidazole (4NI), 2-nitroimidazole (2NI), 1-methyl-4- (Me4NI) and 1-methyl-5-nitroimidazole (Me5NI), and imidazole (IMI) in the presence of a potassium atom and provided a strong basis for the assignment of the lowest unoccupied molecular orbitals accessed in the collision process.

Highlights

The chemical compounds 4-nitroimidazole (4NI, C3 H3 N3 O2, 113 amu), 2-nitroimidazole (2NI, C3 H3 N3 O2, 113 amu), 1-methyl-4-nitroimidazole (Me4NI, C4 H5 N3 O2, 127 amu) and1-methyl-5-nitroimidazole (Me5NI, C4 H5 N3 O2, 127 amu) are nitro group containing molecules belonging to the large family of nitroimidazoles, with their molecular structures schematically shown inInt
4-nitroimidazole (4NI) and 5-nitroimidazole (5NI) concur in a tautomeric equilibrium [21,22] with DFT (Density Functional Theory) calculations showing a relative population of 1:0.7 for 4NI and 5NI at 390 K [7]
The study gives a comprehensive insight on the decomposition mechanisms of neutral imidazole-related compounds (4(5)NI, 2NI, Me4NI, Me5NI, and IMI) in electron transfer collisions with neutral potassium atoms

Summary

Introduction

The chemical compounds 4-nitroimidazole (4NI, C3 H3 N3 O2 , 113 amu), 2-nitroimidazole (2NI, C3 H3 N3 O2 , 113 amu), 1-methyl-4-nitroimidazole (Me4NI, C4 H5 N3 O2 , 127 amu) and1-methyl-5-nitroimidazole (Me5NI, C4 H5 N3 O2 , 127 amu) are nitro group containing molecules belonging to the large family of nitroimidazoles, with their molecular structures schematically shown inInt. The chemical compounds 4-nitroimidazole (4NI, C3 H3 N3 O2 , 113 amu), 2-nitroimidazole (2NI, C3 H3 N3 O2 , 113 amu), 1-methyl-4-nitroimidazole (Me4NI, C4 H5 N3 O2 , 127 amu) and. 1-methyl-5-nitroimidazole (Me5NI, C4 H5 N3 O2 , 127 amu) are nitro group containing molecules belonging to the large family of nitroimidazoles, with their molecular structures schematically shown in. 2019, 20, 6170; doi:10.3390/ijms20246170 www.mdpi.com/journal/ijms Int. Int.J.J.Mol. Mol.Sci

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