The structure of diphosphaallenic radical cations as evidenced by EPR experiments and ab initio calculations

1997 ◽  
pp. 921-926 ◽  
Author(s):  
Mostafa Chentit ◽  
Helena Sidorenkova ◽  
Abdelaziz Jouaiti ◽  
Gustavo Terron ◽  
Michel Geoffroy ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Radical Cations ◽  
Epr Experiments

Cleavage of the radical cations of alkenes; 1-butene and 4,4-dimethyl-1-pentene. Ab initio calculations on the interaction between the allyl and alkyl radical and carbocation moieties

1991 ◽  
Vol 69 (9) ◽  
pp. 1365-1375 ◽  
Author(s):  
Xinyao Du ◽  
Donald R. Arnold ◽  
Russell J. Boyd ◽  
Zheng Shi
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Radical Cation ◽  
Alkyl Radical ◽  
Radical Cations ◽  
Molecular Orbital Calculations ◽  
Allyl Radical ◽  
Allyl Cation ◽  
Tert Butyl ◽  
Carbon Carbon Bond

Carbon–carbon bond cleavage of the radical cations of 1-butene [Formula: see text] and 4,4-dimethyl-1-pentene [Formula: see text] will generate the allyl and alkyl radical and carbocation fragments. Alternative bonding arrangements between the allyl and methyl moieties in [Formula: see text] and between the allyl and tert-butyl moieties in [Formula: see text] possible metastable intermediates or transition states preceding complete separation of the fragments, have been investigated by ab initio molecular orbital calculations. Structures were fully optimized at the UHF/6-31G* or UHF/STO-3G levels, and some of the calculations on [Formula: see text] were expanded with single point MP2/6-31G*//UHF/6-31G* computations. The C4H8+ radical cation, having a structure similar to that of 1-butene, is more stable than the separated fragments: 183 kj mol−1 lower in energy than the sum of the energies of the allyl cation and the methyl radical, and 385 kJ mol−1 lower than the sum of the energies of an allyl radical and a methyl cation, at the MP2/6-31G* level. The corresponding values at the UHF/STO-3G level are 276 and 415 kj mol−1, respectively. There is less bonding interaction between the allyl and tert-butyl moieties in [Formula: see text] The summation of the energies of the allyl radical and tert-butyl cation is 123 kj mol−1 lower than the summation of the energies of the allyl cation and tert-butyl radical, and 115 kJ mol−1 higher in energy than the bonded radical cation [Formula: see text] at the UHF/STO-3G level. These calculated values are compared with thermochemical data and with experimental results on the cleavage of these, and related, radical cations. Key words: radical cation, cleavage, ab initio calculations, electron transfer, photochemistry.

Radical reactions in a single crystal of phosphaalkene: EPR and ab initio calculations of phosphoniumyl radical cations

1995 ◽  
Vol 99 (43) ◽  
pp. 15864-15869 ◽  
Author(s):  
Shrinivasa N. Bhat ◽  
Theo Berclaz ◽  
Michel Geoffroy ◽  
Abdelaziz Jouaiti
Keyword(s):  
Ab Initio Calculations ◽  
Single Crystal ◽  
Ab Initio ◽  
Radical Cations ◽  
Radical Reactions

scholarly journals Stabilities of nanohydrated thymine radical cations: insights from multiphoton ionization experiments and ab initio calculations

2017 ◽  
Vol 71 (7) ◽  
Author(s):  
Rahul Pandey ◽  
Mathieu Lalande ◽  
Michal Ryszka ◽  
Paulo Limão-Vieira ◽  
Nigel J. Mason ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Multiphoton Ionization ◽  
Radical Cations

Ab initio calculations on the group IV tetrafluoride radical cations

1989 ◽  
Vol 137 (1-3) ◽  
pp. 157-164 ◽  
Author(s):  
R.A. Beärda ◽  
H.R.R. Wiersinga ◽  
J.F.M. Aarts ◽  
J.J.C. Mulder
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Radical Cations ◽  
Group Iv

ab i/ifüo-Rechnungen zur relativen Stabilität der Neutralmoleküle, Radikalkationen und -anionen von Allen und Propin / ab initio Calculations on the Relative Stabilities of the Neutrals, Radical Cations and Anions of Allene and Propvne

1982 ◽  
Vol 37 (12) ◽  
pp. 1602-1605 ◽  
Author(s):  
Gemot Frenking ◽  
Helmut Schwarz
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Redox Reactions ◽  
Radical Cations ◽  
Radical Anions ◽  
Electron Affinities ◽  
Relative Stabilities ◽  
Cation Radicals ◽  
Stability Order ◽  
The Stability

Ab initio calculations demonstrate that, in agreement with experimental results, the oxidation of both allene (1) and propyne (2) to their corresponding cation radicals (1+·nd 2+·) is associated with a reversal of the stability order. Whereas for the neutral molecules 1 is thermochemically less stable than 2 (⊿⊿Hf° = 1.3 kcal/mol) the opposite holds for the cation radicals (1+· is 13.3 kcal/mol more stable than 2+·). The radical anions of 1 and 2 do also show a reversed stability order (1+· being 5.1 kcal/mol more stable than 2-·); however, both radical anions are predicted to undergo spontaneous electron detachement, thus giving their neutral counterparts (negative electron affinities). The changes in geometries and charge distributions associated with the redox reactions of 1 and 2 are briefly discussed

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