Université de Neuchâtel

Self-organisation of dodeca-dendronized fullerene into supramolecular discs and helical columns containing a nanowire-like core

Guerra, Sebastiano ; Iehl, Julien ; Holler, Michel ; Peterca, Mihai ; Wilson, Daniela A ; Partridge, Benjamin E ; Zhang, Shaodong ; Deschenaux, Robert ; Nierengarten, Jean-Francois ; Percec, Virgil

In: Chemical Science, 2015, vol. 6, no. 6, p. 3393-3401

Twelve chiral and achiral self-assembling dendrons have been grafted onto a [60]fullerene hexa-adduct core by copper-catalyzed alkyne azide "click" cycloaddition. The structure adopted by these compounds was determined by the self-assembling peripheral dendrons. These twelve dendrons mediate the self-organisation of the dendronized [60]fullerene into a disc-shaped structure containing the...

Université de Neuchâtel

Design of liquid-crystalline gold nanoparticles by click chemistry

Mischler, Sylvain ; Guerra, Sebastiano ; Deschenaux, Robert

In: Chemical Communications, 2012, vol. 48, no. 16, p. 2183-2185

Mesomorphic alkyne-based first- and second-generation dendrons were grafted onto gold nanoparticles carrying azide groups under click reaction conditions. The nanoparticles decorated with the dendrons displayed liquid-crystalline properties and good thermal stability.

Université de Neuchâtel

Piling Up Pillar[5]arenes To Self-Assemble Nanotubes

Nierengarten, Iwona ; Guerra, Sebastiano ; Ben Aziza, Haifa ; Holler, Michel ; Abidi, Rym ; Barberá, Joaquín ; Deschenaux, Robert ; Nierengarten, Jean-François

In: Chemistry – A European Journal, 2016, vol. 22, no. 18, p. 6185-6189

New liquid-crystalline pillar[5]arene derivatives have been prepared by grafting first- generation Percec-type poly(benzylether) dendrons onto the macrocyclic scaffold. The molecules adopt a disc-shaped structure perfectly suited for self-organization into a columnar liquid-crystalline phase. In this way, the pillar[5]arene cores are piled up, thus forming a nanotubular wire encased within a...

Université de Neuchâtel

Macrocyclic Effects in the Mesomorphic Properties of Liquid-Crystalline Pillar[5]- and Pillar[6]arenes

Nierengarten, Iwona ; Guerra, Sebastiano ; Holler, Michel ; Karmazin-Brelot, Lydia ; Barberá, Joaquín ; Deschenaux, Robert ; Nierengarten, Jean-François

In: European Journal of Organic Chemistry, 2013, vol. 2013, no. 18, p. 3675-3684

Whereas the reaction of 1,4-bis(2-bromoethyloxy)benzene (4) with paraformaldehyde in the presence of BF3·Et2O afforded exclusively the cyclopentameric pillar[5]arene derivative (5), both cyclopenta- and cyclohexameric macrocycles 5 and 6 were obtained when the reaction of 4 with paraformaldehyde was performed at 45 °C in CHCl3 with FeCl3 as the...

Université de Neuchâtel

Building liquid crystals from the 5-fold symmetrical pillar[5]arene core

Nierengarten, Iwona ; Guerra, Sebastiano ; Holler, Michel ; Nierengarten, Jean-Francois ; Deschenaux, Robert

In: Chemical Communications, 2012, vol. 48, no. 65, p. 8072-8074

Comparison of the liquid-crystalline properties of a pillar[5]arene core functionalized with 10 mesogenic cyanobiphenyl units with those of a corresponding model compound revealed the strong influence of the macrocyclic pillar[5]arene core on the mesomorphic properties.

Université de Neuchâtel

Liquid-Crystalline Dendrimers Designed by Click Chemistry

Guerra, Sebastiano ; Nguyen, Thi Le Anh ; Furrer, Julien ; Nierengarten, Jean-François ; Barberá, Joaquín ; Deschenaux, Robert

In: Macromolecules, 2016, vol. 49, no. 9, p. 3222-3231

Liquid-crystalline dendrimers have been prepared from second-generation Percec- type poly(benzyl ether) dendrons or second-generation poly(aryl ester) dendrons carrying cyanobiphenyl mesogens. The Janus dendrimer, which combines the two types of dendromesogens, has also been synthesized. Those compounds have been prepared under copper-catalyzed azide–alkyne cycloaddition conditions. The ...

Université de Neuchâtel

La chimie click au service des cristaux liquides : du concept à l'application

Guerra, Sebastiano ; Deschenaux, Robert (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2012 ; 2249.

Our research project deals with the design of liquid-crystalline materials based on the 1,3-dipolar cycloaddition reaction, i.e. the click chemistry. This reaction was found to be effective and versatile, and a great variety of new complex structures could be synthesized, including dendrimers, dendromesogens, gold nanoparticles and polyadducts of fullerenes. In the area of mesomorphic...

Université de Neuchâtel

Accordion-optimized DEPT experiments

Furrer, Julien ; Guerra, Sebastiano ; Deschenaux, Robert

In: Magnetic Resonance in Chemistry, 2011, vol. 49, no. 1, p. 16-22

In this contribution, a pulse sequence is described for recording accordion-optimized DEPT experiments. The proposed ACCORDEPT experiment detects a wide range of one-bond coupling constants using accordion optimization. As a proof of concept, this strategy has been applied to a mesogen containing a large range of one-bond 1JCH coupling constants associated with the various...