Université de Fribourg

Dimer radical cations of indole and indole-3-carbinol: localized and delocalized radical cations of diindolylmethane

Błoch-Mechkour, Anna ; Bally, Thomas ; Marcinek, Andrzej

In: The Journal of Physical Chemistry A, 2011, vol. 115, no. 26, p. 7700–7708

Extending our previous study on the title species (J. Phys. Chem. A2010, 114, 6787), we investigated the dimer cations that are formed on oxidation of the glucobrassin derivatives indole-3-carbinol (I3C) and diindolylmethane (DIM) and of parent indole (I). Radiolysis in ionic liquid and Ar matrices shows that, at sufficiently high concentrations and/or on...

Université de Fribourg

Mechanistic aspects of alloxan diabetogenic activity: a key role of keto-enol inversion of dialuric acid on ionization

Czerwiñska, Małgorzata ; Sikora, Adam ; Szajerski, Piotr ; Adamus, Jan ; Marcinek, Andrzej ; Gębicki, Jerzy ; Bednarek, Paweł

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...

Université de Fribourg

Mechanistic aspects of the oxidative and reductive fragmentation of n-nitrosoamines: a new method for generating nitrenium cations, amide anions, and aminyl radicals

Piech, Krzysztof ; Bally, Thomas ; Sikora, Adam ; Marcinek, Andrzej

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...

Université de Fribourg

Radicals and radical ions derived from indole, indole-3-carbinol and diindolylmethane

Błoch-Mechkour, Anna ; Bally, Thomas ; Sikora, Adam ; Michalski, Radosław ; Marcinek, Andrzej ; Gębicki, Jerzy

In: The Journal of Physical Chemistry A, 2010, vol. 114, no. 25, p. 6787–6794

The primary products, i.e., the radical cations and radicals obtained on oxidation of the glucobrassicin metabolites (and dietary supplements), indole-3-carbinol (I3C) and diindolylmethane (DIM), and those from parent indole (I) are characterized in an ionic liquid and in Ar matrices. The radical cations of I and I3C are stable toward (photo)deprotonation under these conditions, but the resulting...