In: Journal of the American Chemical Society, 2007, vol. 129, no. 11, p. 3211 -3217
A new method for investigating the mechanisms of nitric oxide release from NO donors under oxidative and reductive conditions is presented. Based on the fragmentation of N-nitrosoamines, it allows generation and spectroscopic characterization of nitrenium cations, amide anions, and aminyl radicals. X-irradiation of N-nitroso-N,N-diphenylamine 1 in Ar matrices at...
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In: The Journal of Physical Chemistry A, 2006, vol. 110, no. 3, p. 1163 -1170
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In: Journal of the American Chemical Society, 2006, vol. 128, no. 24, p. 7828 -7834
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In: The Journal of Physical Chemistry A, 2007, vol. 111, no. 9, p. 1667 -1676
The first few bands in the optical spectra of radical cations can often be interpreted in terms of A-type transitions that involve electron promotions from doubly occupied to the singly occupied molecular orbital (SOMO) and/or B-type transition which involve electron promotion from the SOMO to virtual molecular orbitals. We had previously demonstrated that, by making use of Koopmans' theorem, the...
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In: The Journal of Physical Chemistry A, 2006, vol. 110, no. 22, p. 7272 -7278
The inversion of the keto-enol stability order of dialuric acid on ionization was calculated and verified experimentally. The radical cations in both forms were characterized. The spectrum of the keto form was observed upon direct ionization of dialuric acid under matrix conditions, whereas the enol form was formed upon a sequential electron-proton-proton attachment to alloxan under acidic...
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In: Chemistry - A European Journal, 2006, vol. 12(17), p. 4559-4567
Three tricyclic vinylcyclobutanes (3-methylenetricyclo[5.3.0.02,6]decanes 1-3) have been subjected to ionization by photoinduced electron transfer in solution and by X-irradiation in Ar matrices. All three compounds undergo oxidative cycloreversion; the cleavage of the four-membered ring, however, occurs in a different direction depending on the presence of a methyl group...
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In: ChemPhysChem, 2006, vol. 7(6), p. 1268-1275
2,6-Difluorophenylnitrene was reinvestigated both experimentally, in Ar matrices at 10 K, and computationally, by DFT and CASSCF/CASPT2 calculations. Almost-pure samples of both neutral rearrangement products (the bicyclic azirine and the cyclic ketenimine) of a phenylnitrene were prepared and characterized for the first time. These samples were then subjected to X-irradiation in the presence of...
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In: Chemical Physics Letters, 2005, vol. 416(4-6), p. 354
DFT method has been used in combination with various basis sets to model the ionic cycloaddition of cationic heteroaromatic diene, 2,3-dimethylisoquinoliniuim ion with cyclopentadiene with a view to understand the factors that influence the stereochemical outcome of the reaction. Calculations show that this reaction is an inverse electron demand type reaction and it passes through highly...
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Thèse de doctorat : Université de Fribourg, 2000 ; Nr. 1299.
On ionization of [1.1.1]propellane (PRP+.) in cryogenic matrices a photolabile species with a broad, weak NIR band (λmax = 1440 nm) and an ESR spectrum consisting of a 14.8 G quintet of 5.4 G triplets is formed. On NIR irradiation this species is converted into the radical cation of vinylidenecyclopropane (VCP+.), which was generated independently by ionization of VCP. Quantum chemical...
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In: Chemistry - A European Journal, 2005, vol. 11(4), p. 1294-1304
Radical cations were generated from different phenyl-substituted aziridines by pulse radiolysis in aqueous solution containing TlOH.+, N₃. or SO₄.- as oxidants or in n-butyl chloride, by ⁶⁰Co γ radiolysis in Freon matrices at 77 K, and in some cases by flash photolysis in aqueous solution. Depending on the substitution pattern of the aziridines, two...
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