Insights into 2- and 4(5)-Nitroimidazole Decomposition into Relevant Ions and Molecules Induced by VUV Ionization

Cartoni, Antonella; Casavola, A.; Bolognesi, P.; Castrovilli, Mattea Carmen; Catone, Daniele; Chiarinelli, Jacopo; Richter, Robert; Avaldi, L.

doi:10.1021/acs.jpca.8b01144

Cited by 25 publications

(57 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…of the N + 2 cations, and the corresponding threshold appearance energies (AEs). In the VUV photoionization studies of three nitroimidazole isomers (used as radiosensitizers in radiotherapy), isomeric effects in the efficiencies and occurrence of decomposition channels of five-membered molecular ring was observed and correlated with position of the nitro NO 2 side-group [6].…”

Section: Introductionmentioning

confidence: 99%

Electron impact ionization and cationic fragmentation of the pyridazine molecules

2018

View full text Add to dashboard Cite

Electron impact mass spectroscopy was used to investigate ionization and cationic fragmentation of the pyridazine (1,2 diazine), C4H4N2, molecules in the gas phase. The mass spectra were measured and the observed mass peaks assigned to the corresponding cations. The appearance energies of most of the cationic fragments were determined and the possible fragmentation processes are discussed. The total cross section for electron impact ionization of pyridazine was calculated using the binary-encounter-Bethe (BEB) model. The calculated cross section was applied to normalize the measured cation yield curves and total and partial cross sections for ionization and cationic fragmentation were obtained over the energy range from the respective ionization thresholds to 140 eV.

show abstract

Section: Introductionmentioning

confidence: 99%

Electron impact ionization and cationic fragmentation of the pyridazine molecules

2018

View full text Add to dashboard Cite

show abstract

“…The nitro N (6) chemical shift may be as a result of the ionic configuration [9] and the availability of the nitro (-NO 2 ) for ionization. [49] As a result, to accurately determine and understand the electronic structures of nitroimidazole derivatives, further combined configuration and phase specific methods with molecular dynamics are needed. [50] Conclusion 4-Nitroimidazole (4-NI) and 1-methyl-4-nitromidazole (CH 3 -4NI) are of importance as pharmaceutical ingredients.…”

Section: Resultsmentioning

confidence: 99%

NMR Chemical Shift and Methylation of 4-Nitroimidazole: Experiment and Theory

et al. 2021

View full text Add to dashboard Cite

Nitroimidazoles and derivatives are a class of active pharmaceutical ingredients (APIs) first introduced sixty years ago. As anti-infection agents, the structure-activity relationships of nitroimidazole compounds have been particularly difficult to study due to their low reduction potentials and unique electronic structures. In this study, we combine dynamic nuclear polarization (DNP)-enhanced solid-state (100 K), solid-state (298 K), and 1 H-13 C heteronuclear single quantum coherence (HSQC) solution-state NMR techniques (303 K) with density functional theory (DFT) to study the 1 H, 13 C, and 15 N chemical shifts of 4-nitroimidazole (4-NI) and 1-methyl-4-nitroimidazole (CH 3-4NI). The 4-NI chemical shifts were observed at 119.4, 136.4, and 144.7 ppm for 13 C, and at 181.5, 237.4, and 363.0 ppm for 15 N. The measurements revealed that methylation (deprotonation) of the amino nitrogen N (1) of 4-NI had less effect (Dd ¼ À4.8 ppm) on the N (1) chemical shift but was compensated by shielding of the N (3) (Dd ¼ 11.6 ppm) in CH 3-4NI. The calculated chemical shifts using DFT for 4-NI and CH 3-4NI agreed well with the experimental values (within 2 %) for the imidazole carbons. However, larger discrepancies (up to 13 %) were observed between the calculated and measured 15 N NMR chemical shifts for the imidazole nitrogen atoms of both molecules, which indicate that effects such as imidazole ring resonant structures and molecular dynamics may also contribute to the nitrogen chemical environment.

show abstract

“…The description of the CiPo beamline at ELETTRA has been reported previously . Briefly, the beamline is equipped with an electromagnetic elliptical undulator/wiggler and a Normal Incidence Monochromator (NIM) to cover the vacuum ultraviolet (VUV) 8–40 eV energy range.…”

Section: Methodsmentioning

confidence: 99%

The Reaction of Sulfur Dioxide Radical Cation with Hydrogen and its Relevance in Solar Geoengineering Models

et al. 2020

Self Cite

View full text Add to dashboard Cite

SO2 has been proposed in solar geoengineering as a precursor of H2SO4 aerosol, a cooling agent active in the stratosphere to contrast climate change. Atmospheric ionization sources can ionize SO2 into excited states of SO2·+ , which quickly reacts with trace gases in the stratosphere. In this work we explore the reaction of H2D2 with SO2·+ excited by tunable synchrotron radiation, leading to HSO2++H (DSO2++D ), where H contributes to O3 depletion and OH formation. Density Functional Theory and Variational Transition State Theory have been used to investigate the dynamics of the title barrierless and exothermic reaction. The present results suggest that solar geoengineering models should test the reactivity of SO2·+ with major trace gases in the stratosphere, such as H2 since this is a relevant channel for the OH formation during the nighttime when there is not OH production by sunlight. OH oxides SO2, triggering the chemical reactions leading to H2SO4 aerosol.

show abstract

Insights into 2- and 4(5)-Nitroimidazole Decomposition into Relevant Ions and Molecules Induced by VUV Ionization

Cited by 25 publications

References 51 publications

Electron impact ionization and cationic fragmentation of the pyridazine molecules

Electron impact ionization and cationic fragmentation of the pyridazine molecules

NMR Chemical Shift and Methylation of 4-Nitroimidazole: Experiment and Theory

The Reaction of Sulfur Dioxide Radical Cation with Hydrogen and its Relevance in Solar Geoengineering Models

Contact Info

Product

Resources

About