Université de Neuchâtel

Amphiphilic Fullerene-Cholesterol Derivatives: Synthesis and Preparation of Langmuir and Langmuir-Blodgett Films

Felder, Delphine ; Carreón, Maria del Pilar ; Gallani, Jean-Louis ; Guillon, Daniel ; Nierengarten, Jean-François ; Chuard, Thierry ; Deschenaux, Robert

In: Helvetica Chimica Acta, 2001, vol. 84, no. 5, p. 1119-1132

Amphiphilic fullerene bis-adducts 11 and 14 containing two and four cholesterol moieties, respectively, were prepared starting from the corresponding bis-malonate derivatives. In a systematic study, their spreading behavior at the air-water interface was compared to that of bis-adduct 6 with no polar head-group. Compared to 6, for which some three-dimensional...

Université de Neuchâtel

Aromatic Bent-Core Liquid Crystals: an Opportunity for Introducing Terdentate Binding Units into Mesophases

Nozary, Homayoun ; Piguet, Claude ; Rivera, Jean-Pierre ; Tissot, Paul ; Morgantini, Pierre-Yves ; Weber, Jacques ; Bernardinelli, Gérald ; Bünzli, Jean-Claude G. ; Deschenaux, Robert ; Donnio, Bertrand ; Guillon, Daniel

In: Chemistry of Materials, 2012, vol. 14, no. 3, p. 1075–1090

Lipophilic linear semirigid side arms containing two or three successive phenyl rings separated by carboxylate spacers have been connected to the 5 or 6 positions of bent aromatic terdentate 2,6-bis(benzimidazol-2-yl)pyridine binding units to give extended V-shaped (L11) and I-shaped receptors (L12, L12b, and L13). The carboxylate spacers limit the flexibility of the...

Université de Neuchâtel

Bent Tridentate Receptors in Calamitic Mesophases with Predetermined Photophysical Properties: New Luminescent Lanthanide-Containing Materials

Nozary, Homayoun ; Piguet, Claude ; Tissot, Paul ; Bernardinelli, Gérald ; Bünzli, Jean-Claude G. ; Deschenaux, Robert ; Guillon, Daniel

In: Journal of the American Chemical Society (JACS), 1998, vol. 120, no. 47, p. 12274–12288

A new synthetic strategy has been developed to introduce bent and rigid tridentate 2,6-bis(benzimidazol-2‘-yl)pyridine cores into rodlike ligands L11-17. The crystal structure of the nonmesogenic ligand L13 (C39H37N5O4, triclinic, P1̄, Z = 2) shows the expected trans−trans conformation of the tridentate...

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 Neuchâtel

Encoding calamitic mesomorphism in thermotropic lanthanidomesogens

Terazzi, Emmanuel ; Bocquet, Bernard ; Campidelli, Stéphane ; Donnio, Bertrand ; Guillon, Daniel ; Deschenaux, Robert ; Piguet, Claude

In: Chemical Communications (ChemComm), 2006, vol. 27, p. 2922-2924

Peripheral cyanobiphenyl dendrimers impose a microphase organization compatible with smectic mesomorphism, in which the bulky nine-coordinate lanthanide core is located between the decoupled mesogenic sublayers made up of parallel cyanobiphenyl groups.

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

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

Ferrocene-Containing Thermotropic Side-Chain Liquid-Crystalline Polysiloxanes

Deschenaux, Robert ; Jauslin, Isabelle ; Scholten, Ulrich ; Turpin, François ; Guillon, Daniel ; Heinrich, Benoît

In: Macromolecules, 1998, vol. 31, no. 17, p. 5647–5654

The synthesis, purification, characterization, and liquid-crystalline properties of side-chain polysiloxanes bearing mesomorphic 1,1‘- or 1,3-disubstituted ferrocene units are reported. The polymers were prepared by grafting the appropriate vinyl-containing ferrocene monomer onto commercially available poly(hydrosiloxane)s following a standard procedure. The monomers gave smectic A or smectic A...

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

Hexacatenar liquid-crystalline complexes of palladium(II) and platinum(II) based on trialkoxystilbazole esters

Plasseraud, Laurent ; Gonzalez Cuervo, Laura ; Guillon, Daniel ; Süss-Fink, Georg ; Deschenaux, Robert ; Bruce, Duncan W. ; Donnio, Bertrand

In: Journal of Materials Chemistry, 2002, vol. 12, p. 2653-2658

The synthesis and characterisation of 4-(3,4,5-trialkoxybenzoyloxy)pyridines (1a–e), and of their corresponding palladium(II), (2a–e), and platinum(II), (3a–e), complexes are described. The pyridine-based ligands are not mesomorphic, but upon complexation to PdCl2 or PtCl2, new hexacatenar mesogens are formed which show exclusively the hexagonal...