Theoretical Calculations on the Cycloreversion of Oxetane Radical Cations

2005 ◽  
Vol 109 (11) ◽  
pp. 2602-2607 ◽  
Author(s):  
M. Angeles Izquierdo ◽  
Luis R. Domingo ◽  
Miguel A. Miranda
Keyword(s):  
Theoretical Calculations ◽  
Radical Cations

scholarly journals Substituent Effects on EI-MS Fragmentation Patterns of 5-Allyloxy-1-aryl-tetrazoles and 4-Allyl-1-aryl-tetrazole-5-ones; Correlation with UV-Induced Fragmentation Channels

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3282
Author(s):  
Alina Secrieru ◽  
Rabah Oumeddour ◽  
Maria L. S. Cristiano
Keyword(s):  
Theoretical Calculations ◽  
Substituent Effects ◽  
Radical Cations ◽  
Electronic Effects ◽  
Diverse Range ◽  
The Matrix ◽  
Electron Impact Mass ◽  
Fragmentation Patterns ◽  
Tetrazole Derivatives ◽  
Impact Mass

1,4- and 1,5-disubstituted tetrazoles possess enriched structures and versatile chemistry, representing a challenge for chemists. In the present work, we unravel the fragmentation patterns of a chemically diverse range of 5-allyloxy-1-aryl-tetrazoles and 4-allyl-1-aryl-tetrazolole-5-ones when subjected to electron impact mass spectrometry (EI-MS) and investigate the correlation with the UV-induced fragmentation channels of the matrix-isolated tetrazole derivatives. Our results indicate that the fragmentation pathways of the selected tetrazoles in EI-MS are highly influenced by the electronic effects induced by substitution. Multiple pathways can be envisaged to explain the mechanisms of fragmentation, frequently awarding common final species, namely arylisocyanate, arylazide, arylnitrene, isocyanic acid and hydrogen azide radical cations, as well as allyl/aryl cations. The identified fragments are consistent with those found in previous investigations concerning the photochemical stability of the same class of molecules. This parallelism showcases a similarity in the behaviour of tetrazoles under EI-MS and UV-irradiation in the inert environment of cryogenic matrices of noble gases, providing efficient tools for reactivity predictions, whether for analytical ends or more in-depth studies. Theoretical calculations provide complementary information to articulate predictions of resulting products.

Aryl Sulfoxide Radical Cations. Generation, Spectral Properties, and Theoretical Calculations

2006 ◽  
Vol 110 (32) ◽  
pp. 9940-9948 ◽  
Author(s):  
Enrico Baciocchi ◽  
Tiziana Del Giacco ◽  
Maria Francesca Gerini ◽  
Osvaldo Lanzalunga
Keyword(s):  
Spectral Properties ◽  
Theoretical Calculations ◽  
Radical Cations

Structures of 4-substituted thioanisole radical cations studied by time-resolved resonance Raman spectroscopy during pulse radiolysis and theoretical calculations

RSC Advances ◽  
2016 ◽  
Vol 6 (111) ◽  
pp. 109334-109339 ◽  
Author(s):  
Sachiko Tojo ◽  
Mamoru Fujitsuka ◽  
Tetsuro Majima
Keyword(s):  
Raman Spectroscopy ◽  
Pulse Radiolysis ◽  
Dft Calculation ◽  
Theoretical Calculations ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Radical Cations ◽  
Time Resolved ◽  
Spin Distributions

The structures of 4-substituted thioanisole radical cations were studied by time-resolved resonance Raman spectroscopy during pulse radiolysis and DFT calculation, indicating importance of charge and spin distributions toward the dimerization.

ChemInform Abstract: ESR Studies of P2H+ 6 and PH+ 3 Radical Cations in Rare Gas Matrices at 4 K. Comparison with Theoretical Calculations.

ChemInform ◽  
2010 ◽  
Vol 25 (9) ◽  
pp. no-no
Author(s):  
L. B. JUN. KNIGHT ◽  
D. J. TYLER ◽  
P. KUDELKO ◽  
J. B. LYON ◽  
A. J. MCKINLEY
Keyword(s):  
Theoretical Calculations ◽  
Radical Cations ◽  
Rare Gas

Hydrogen atom transfer in the radical cations of tryptophan-containing peptides AW and WA studied by mass spectrometry, infrared multiple-photon dissociation spectroscopy, and theoretical calculations

2018 ◽  
Vol 25 (1) ◽  
pp. 112-121 ◽  
Author(s):  
Andrii Piatkivskyi ◽  
Justin Kai-Chi Lau ◽  
Giel Berden ◽  
Jos Oomens ◽  
Alan C Hopkinson ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Gas Phase ◽  
Radical Cation ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Radical Cations ◽  
Hydrogen Atom Transfer ◽  
Collision Induced Dissociation ◽  
Infrared Multiple Photon Dissociation ◽  
Nitrogen Radical

Two types of radical cations of tryptophan—the π-radical cation and the protonated tryptophan-N radical—have been studied in dipeptides AW and WA. The π-radical cation produced by removal of an electron during collision-induced dissociation of a ternary Cu(II) complex was only observed for the AW peptide. In the case of WA, only the ion corresponding to the loss of ammonia, [WA–NH3] •+, was observed from the copper complex. Both protonated tryptophan-N radicals were produced by N-nitrosylation of the neutral peptides followed by transfer to the gas phase via electrospray ionization and subsequent collision-induced dissociation. The regiospecifically formed N• species were characterized by infrared multiple-photon dissociation spectroscopy which revealed that the WA tryptophan-N• radical remains the nitrogen radical, while the AW nitrogen radical rearranges into the π-radical cation. These findings are supported by the density functional theory calculations that suggest a relatively high barrier for the radical rearrangement (N• to π) in WA (156.3 kJ mol−1) and a very low barrier in AW (6.1 kJ mol−1). The facile hydrogen atom migration in the AW system is also supported by the collision-induced dissociation of the tryptophan-N radical species that produces fragments characteristic of the tryptophan π-radical cation. Gas-phase ion–molecule reactions with n-propyl thiol have also been used to differentiate between the π-radical cations (react by hydrogen abstraction) and the tryptophan-N• species (unreactive) of AW.

Syntheses, structures and theoretical calculations of stable triarylarsine radical cations

2018 ◽  
Vol 54 (12) ◽  
pp. 1493-1496 ◽  
Author(s):  
Tao Li ◽  
Gengwen Tan ◽  
Cheng Cheng ◽  
Yue Zhao ◽  
Li Zhang ◽  
...  
Keyword(s):  
Radical Cation ◽  
Epr Spectroscopy ◽  
Theoretical Calculations ◽  
Radical Cations ◽  
X Ray ◽  
X Ray Crystallography ◽  
Radical Cation Salts

Two stable triarylarsine radical cation salts have been synthesized and fully characterized by X-ray crystallography and EPR spectroscopy.

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