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Université de Fribourg

Chemical nucleation of diamond films

Mandal, Soumen ; Thomas, Evan L. H. ; Jenny, Titus A. ; Williams, Oliver A.

In: ACS Applied Materials & Interfaces, 2016, vol. 8, no. 39, p. 26220–26225

With the large differences in surface energy between film and substrate in combination with the low sticking coefficient of hydrocarbon radicals, nanocrystalline diamond growth on foreign substrates typically results in poor nucleation densities. A seeding technique is therefore required to realize pinhole-free and thin coalesced films. In this work, a chemical nucleation method for growth of...

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.

In: Journal of Materials Chemistry, 2007, vol. 17, no. 13, p. 1262-1267

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

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...

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

Laterally stretched polycyclic aromatic hydrocarbons: synthesis of dibenzophenanthroheptaphene and tetrabenzotriphenylenopyranthrene derivatives

Alameddine, Bassam ; Anju, Rajamohanan Sobhana ; Shetty, Suchetha ; Baig, Noorullah ; Al-Sagheer, Fakhreia ; Al-Mousawi, Saleh ; Jenny, Titus A.

In: New Journal of Chemistry, 2017, vol. 41, no. 13, p. 6025–6032

Efficient methods for the synthesis of dibenzophenanthroheptaphene (DBPH) and tetrabenzotriphenylenopyranthrene (TBTP) were developed. As a result, a series of unprecedented derivatives of DBPH (1a–c) and TBTP (2a–b) were conventionally obtained from the Scholl cyclodehydrogenation reaction of their respective tribenzopentaphene synthons. An alternative convergent synthesis of DBPH is also...

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

Puckering behavior in six new phosphoric triamides containing aliphatic six- and seven-membered ring groups and a database survey of analogous ring-containing structures

Alviri, Banafsheh Vahdani ; Pourayoubi, Mehrdad ; Saneei, Anahid ; Keikha, Mojtaba ; Lee, Arie van der ; Crochet, Aurélien ; Ajees, A. Abdul ; Nečas, Marek ; Fromm, Katharina M. ; Damodaran, Krishnan ; Jenny, Titus A.

In: Tetrahedron, 2018, vol. 74, no. 1, p. 28–41

The influence of a N heteroatom on the ring conformations of six- and seven- membered aliphatic rings in six new C(O)NHP(O)-based phosphoric triamide structures (analysed by X-ray crystallography) is investigated. Additionally the influence of steric and crystal packing effects is also studied by the analysis of Hirshfeld surfaces. The results are compared to analogous structures with three-...

Université de Fribourg

Self-aggregated perfluoroalkylated hexa-peri-hexabenzocoronene fibers observed by cryo-SEM and fluorescence spectroscopy

Aebischer, Olivier F. ; Aebischer, Annina ; Tondo, Patrick ; Alameddine, Bassam ; Dadras, Massoud ; Güdel, Hans-Ulrich ; Jenny, Titus A.

In: Chemical Communications, 2006, p. 4221 - 4223

The self-assembled architectures in solution of a new HBC derivative bearing perfluoroalkylated side chains were investigated by optical excitation and emission spectroscopy and correlated to cryo-SEM, a new technique in organic chemistry.