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Université de Fribourg

Influence of linear and branched perfluoroalkylated side chains on the π–π stacking behaviour of hexa-peri-hexabenzocoronene and thermotropic properties

Alameddine, Bassam ; Aebischer, Olivier Frédéric ; Heinrich, Benoît ; Guillon, Daniel ; Donnio, Bertrand ; Jenny, Titus A.

In: Supramolecular Chemistry, 2014, vol. 26, no. 2, p. 125–137

The thermotropic properties and self-assembly of two different series of hexa-peri-hexabenzocoronenes (HBC) bearing either linear or branched perfluoroalkylated side chains, each with a wide range of alkyl spacer and perfluorinated tail lengths, have been studied. Correlations between thermogravimetric analysis, differential scanning calorimetry, polarised optical microscopy and small-angle X-ray...

Université de Fribourg

Synthesis of alkyl-Substituted tribenzopentaphenes as versatile polycondensed aromatic hydrocarbon π-π stacking building blocks

Alameddine, Bassam ; Caba, Sofia Martin ; Schindler, Mauro ; Jenny, Titus A.

In: Synthesis, 2012, vol. 44, p. 1928-1934

We show the versatile synthesis of four tribenzopentaphene derivatives bearing alkyl side chains at three different positions. Substitutions on two of these positions led to subtle intensity changes at the lines of the blue emission, whereas alkylation in the bay region led to dimerization of the pentaphene derivative, resulting in a distortion of the chromophore geometry and an emission shift to...

Université de Fribourg

Synthesis of Hexa-peri-hexobenzocoronenes Carrying Linear or Branched Perfluoroalkylated Side Chains

Aebischer, Olivier F. ; Muñoz, David T. ; Tondo, Patrick ; Débieux, Jean-Luc ; Jenny, Titus A.

In: Synthesis, 2010, vol. 7, p. 1123-1140

Substituted disc-shaped perfluoroalkylated hexa-peri-hexabenzocoronenes (HBC), known to self-assemble into conducting ordered architectures, were synthesized and characterized. A systematic variation of the linear or branched perfluoroalkylated side chains was performed in order to screen the influence of the lateral chain on their one-dimensional self-aggregation.

Université de Fribourg

Thermal runaway of dried sewage sludge granules in storage tanks

Poffet, Martine S. ; Käser, Kurt ; Jenny, Titus A.

In: Chimia, 2008, vol. 62, no. 1-2, p. 29-34

Elimination of the sewage sludge from urban wastewater occurs exclusively by incineration in Switzerland, because recycling as fertilizer in agriculture has been banned since October 2006. Two options exist for elimination, either thermal elimination of a thickened sludge in a household waste incineration plant, or drying of the thickened sludge to yield a granular material fit for storage and...

Université de Fribourg

Controlling the lateral aggregation of perfluoroalkylated hexa-peri-hexabenzocoronenes

Aebischer, Olivier F. ; Aebischer, Annina ; Donnio, Bertrand ; Alameddine, Bassam ; Dadras, Massoud ; Güdel, Hans-Ulrich ; Guillon, Daniel ; Jenny, Titus A.

The investigation of two hexa-peri-hexabenzocoronene (HBC) derivatives carrying linear or branched perfluoroalkylated side chains is reported. Polycondensed aromatic hydrocarbons (PAH) such as HBC derivatives are well known to self-organize to form highly ordered monomolecular stacks, which in turn show a concentration- and solvent-dependent lateral aggregation. However, possible...

Université de Fribourg

Yeast sphingolipids do not need to contain very long chain fatty acids

Cerantola, Vanessa ; Vionnet, Christine ; Aebischer, Olivier F. ; Jenny, Titus A. ; Knudsen, Jens ; Conzelmann, Andreas

In: Biochemical Journal, 2007, vol. 401, no. 1, p. 205-216

Synthesis of VLCFAs (very long chain fatty acids) and biosynthesis of DHS (dihydrosphingosine) both are of vital importance for Saccharomyces cerevisiae. The bulk of VLCFAs and DHS are used for ceramide synthesis by the Lag1p (longevity-assurance gene 1)/Lac1p (longevity-assurance gene cognate 1)/Lip1p (Lag1p/Lac1p interacting protein) ceramide synthase. LAG1 and LAC1 are...

Université de Fribourg

Synthesis of perfluoroalkylated bulky triarylamines

Alameddine, Bassam ; Savary, Corinne ; Aebischer, Olivier ; Jenny, Titus A.

In: Synthesis, 2007, p. 271-276

The synthesis of two new triarylamine compounds bearing perfluoroalkylated side chains is described. Good thermal stabilities combined with a blue emission make these compounds promising candidates for materials applications.

Université de Fribourg

Possible ring structures of armchair single-walled carbon nanotubes

Tamilmani, Venkatachalam ; Daul, Claude A. ; Jenny, Titus A.

In: Chimia, 2006, vol. 60, no. 4, p. 228-230

Energetics and the electronic structure of various types of single-walled carbon nanotubes have been investigated by using Density Functional Theory. Armchair [n,n], zigzag [n,0] and chiral [n,m] C₄₀H₂₀ nanotubes have been considered. Calculations show that the armchair isomer is the most stable among the three types and they further reveal the factors that stabilize this isomer....

Université de Fribourg

Synthesis of Novel Fluorinated Hexa-peri-hexabenzocoronenes

Aebischer, Olivier F. ; Tondo, Patrick ; Alameddine, Bassam ; Jenny, Titus A.

In: Synthesis, 2006, vol. 17, p. 2891–2896

The synthesis of several perfluoroalkylated hexabenzocoronene derivatives is described. The substituents range from linear semiperfluoroalkylated chains to branched perfluoroalkylated chains. Novel strategies were applied to overcome the low solubility and the low reactivity of such chains.

Université de Fribourg

Geometry determination of tetrasubstituted stilbenes by proton NMR spectroscopy

Fluxá, Viviana S. ; Jenny, Titus A. ; Bochet, Christian G.

In: Tetrahedron Letters, 2005, vol. 46(2), p. 3793-3795

A simple spectroscopic method was applied to determine the geometry of tetrasubstituted alkenes. The observation of the ⁵J-coupling constants in proton NMR spectra on the ¹³C satellite signals could confirm the previous misassignment of 2,3-diphenylbutene. Hence, the (E)-isomer showed a 1.5 Hz coupling constant, whereas the (Z)-isomer showed a 1.1 Hz coupling constant. Based on this new...