Université de Fribourg

Electronic structure and absorption spectra of biferrocenyl and bisfulvalenide diiron radical cations: detection and assignment of new low-energy transitions

Warratz, Ralf ; Aboulfadl, Hanane ; Bally, Thomas ; Tuczek, Felix

In: Chemistry - A European Journal, 2009, vol. 15, no. 7, p. 1604 - 1617

Low-energy electronic transitions have been detected spectroscopically in the FeII-FeIII mixed-valent biferrocenyl radical cation, but are absent in the spectra of the neutral analogue. They have been assigned by time-dependent DFT calculations (squares in figure). Analogous investigations were performed for the bisfulvalenide FeII-FeIII radical cation....

Université de Fribourg

Photochemistry of reactive intermediates

Bally, Thomas

In: Chimia, 2007, vol. 61, no. 10, p. 645-649

This paper illustrates the research on the photochemistry of reactive intermediates that was (and still is) carried out in the author's research group on three typical examples: the photochemistry of arylcarbenes, arylnitrenes, and organic radical cations.

Université de Fribourg

Oxidative rearrangements of tricyclic vinylcyclobutane derivatives

Grota, Juliane ; Mattay, Jochen ; Piech, Krzysztof ; Bally, Thomas

In: Chemistry - A European Journal, 2006, vol. 12(17), p. 4559-4567

Three tricyclic vinylcyclobutanes (3-methylenetricyclo[,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...

Université de Fribourg

Experimental and theoretical study of 2,6-difluorophenylnitrene, its radical cation, and their rearrangement products in argon matrices

Carra, Claudio ; Nussbaum, Rafael ; Bally, Thomas

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...

Université de Fribourg

Radical Cations of Phenyl-Substituted Aziridines: What Are the Conditions for Ring Opening ?

Gaebert, Carsten ; Mattay, Jochen ; Toubartz, Marion ; Steenken, Steen ; Müller, Beat ; Bally, Thomas

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...