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 Neuchâtel

Mesomorphic Hexabenzocoronenes Bearing Perfluorinated Chains

Alameddine, Bassam ; Aebischer, Olivier F. ; Amrein, Walter ; Donnio, Bertrand ; Deschenaux, Robert ; Guillon, Daniel ; Savary, Corinne ; Scanu, David ; Scheidegger, Oliver ; Titus A. , Jenny

In: Chemistry of Materials, 2005, vol. 17, no. 19, p. 4798–4807

Synthesis and characterization of new hexabenzocoronene (HBC) derivatives bearing perfluoroalkylated chains are described. These disc-shaped polycondensed aromatic hydrocarbons are known to self-assemble by π-stacking into columnar architectures. The peripheral decoration with perfluorinated chains, well-known for their low van der Waals forces, leads as expected to reduced intercolumnar...

Université de Fribourg

Tribenzopentaphene derivatives with lateral aromatic groups: the effect of the nature and position of substituents on emission properties

Alameddine, Bassam ; Anju, Rajamohanan Sobhana ; Al-Sagheer, Fakhreia ; Jenny, Titus A.

In: New Journal of Chemistry, 2016, vol. 40, no. 12, p. 10363–10370

Nine new derivatives of the trapezoidal tribenzopentaphene (TBP) polycyclic aromatic hydrocarbon (PAH) were synthesized via the Suzuki–Miyaura palladium catalyzed cross-coupling reaction. The novel TBP derivatives, which bear various rigid and flexible aromatic groups either at their more accessible (R1) or congested (R2) bases, were fully characterized using high resolution mass...

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

Theoretical study of the stacking behavior of selected polycondensed aromatic hydrocarbons with various symmetries

Antony, Jens ; Alameddine, Bassam ; Jenny, Titus A. ; Grimme, Stefan

In: The Journal of Physical Chemistry A, 2012, vol. 117, no. 3, p. 616–625

Stacked dimers of four polycondensed aromatic hydrocarbons, with structures varying from high to reduced symmetries, have been calculated with dispersion-corrected density functional theory. The configurations of the stacked dimers are readily classified by two in-plane displacements and a relative rotation. The potential energy surface in these three coordinates was calculated with rigid...

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 and investigation of new large self-assembled supramolecules as potential electron emitters

Alameddine, Bassam ; Jenny, Titus (Dir.)

Thèse de doctorat : Université de Fribourg, 2004 ; no 1440.

La nanotechnologie, domaine de recherche qui couvre plusieurs branches scientifiques en Médecine, Biologie, Physique et Chimie, est en pleine expansion dans les institutions de recherche et suscite un vif intérêt dans l’industrie vu ses prometteuses applications. Ceci est dû à plusieurs raisons, parmi lesquelles, on note le control à une échelle moléculaire ce qui augmente...

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

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

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.