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

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 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 Neuchâtel

Liquid-Crystalline [60]Fullerene-TTF Dyads

Allard, Emmanuel ; Oswald, Frédéric ; Donnio, Bertrand ; Guillon, Daniel ; Delgado, Juan Luis ; Langa, Fernando ; Deschenaux, Robert

In: Organic Letters, 2005, vol. 7, no. 3, p. 383-386

[60]Fullerene was functionalized with a TTF derivative and a bis-mesogenic fragment. The synthetic methodology was based on the addition of a malonate derivative to C60 (Bingel-type reaction). Both the malonate and dyad showed smectic B and A phases. The supramolecular organization within the smectic layers was of the monolayer type for the malonate and of the bilayer type for the...

Université de Neuchâtel

Ferrocene-Containing Optically Active Liquid-Crystalline Side-Chain Polysiloxanes with Planar Chirality

Brettar, Julie ; Bürgi, Thomas ; Donnio, Bertrand ; Guillon, Daniel ; Klappert, Rolf ; Scharf, Toral ; Deschenaux, Robert

In: Advanced Functional Materials, 2005, vol. 16, p. 260 - 267

Optically active liquid-crystalline side-chain polysiloxanes have been prepared by grafting planar chiral ferrocene-based vinyl monomers onto commercially available polyhydrosiloxane. Two ferrocene monomers have been synthesized: a linear-type monomer, which displays a monotropic chiral smectic C (SC*) phase and enantiotropic smectic A (SA) and chiral N (N*) phases, and a laterally...

Université de Neuchâtel

Liquid-crystalline fullerene–oligophenylenevinylene conjugates

Campidelli, Stéphane ; Deschenaux, Robert ; Eckert, Jean-François ; Guillon, Daniel ; Nierengarten, Jean-François

In: Chemical Communications, 2002, p. 656 - 657

Functionalization of C60–oligophenylenevinylene derivatives with a cyanobiphenyl-terminated dendromesogen leads to new donor–acceptor systems with liquid-crystalline properties.

Université de Neuchâtel

Fullerene-containing liquid-crystalline dendrimers

Dardel, Blaise ; Guillon, Daniel ; Heinrich, Benoît ; Deschenaux, Robert

In: Journal of Materials Chemistry, 2001, vol. 11, p. 2814 - 2831

Addition reaction of mesomorphic malonate-based dendrimers (up to the fourth generation) with C60 gave liquid-crystalline fullerene derivatives. The cyanobiphenyl unit was used as liquid-crystalline promoter. The malonates presented nematic and/or smectic A phases. The fullerenes showed only smectic A phases, with the exception of the second generation dendrimer for which smectic A and...

Université de Neuchâtel

Ferrocene-Containing Thermotropic Side-Chain Liquid-Crystalline Polymethacrylate from a Mesomorphic Trisubstituted Ferrocene Monomer

Deschenaux, Robert ; Guillon, Daniel

In: Macromolecules, 1997, vol. 30, no. 13, p. 3759–3765

The synthesis and mesomorphic properties of a methacrylate-containing ferrocene monomer bearing two flexible chains at the 1,1‘-positions and the corresponding side-chain homopolymer are described. Both polymer and monomer showed enantiotropic smectic C and smectic A phases. The liquid-crystalline phases were fully characterized by means of X-ray diffraction experiments. Dilatometric...

Université de Neuchâtel

Liquid-crystalline fullerodendrimers

Deschenaux, Robert ; Donnio, Bertrand ; Guillon, Daniel

In: New Journal of Chemistry (NJC), 2007, vol. 31, no. 7, p. 1064 - 1073

Addition of liquid-crystalline dendrimers onto [60]fullerene led to thermotropic liquid crystals which displayed various types of mesophases, including chiral nematic, smectic B, smectic A and columnar phases. This approach represents an interesting way for the design of self-organized structures based on [60]fullerene, and opens the way to optoelectronic applications for this carbon allotrope,...

Université de Neuchâtel

Liquid-crystalline mixed [60]fullerene–ferrocene materials

Deschenaux, Robert ; Even, Michael ; Guillon, Daniel

In: Chemical Communications (ChemComm), 1998, vol. 5, p. 537-538

[60]Fullerene was functionalized with a mesomorphic malonate derivative containing two ferrocene units; the targeted compound showed thermotropic liquid-crystalline properties.