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Deschenaux, Robert

Nom
Deschenaux, Robert
Affiliation principale
Fonction
Professeur.e ordinaire
Email
Robert.Deschenaux@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/384
_
0000-0002-1142-0022

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  • Publication
    Métadonnées seulement
    Amphiphilic and mesomorphic fullerene-based dendrimers
    (2003)
    Guillon, Daniel
    ;
    Nierengarten, Jean-Francois
    ;
    Gallani, Jean-Louis
    ;
    Eckert, Jean-Francois
    ;
    Rio, Yannick
    ;
    del Pilar Carreon, Maria
    ;
    Dardel, Blaise
    ;
    Deschenaux, Robert 
    Growing attention is currently devoted to large dendritic structures for applications in nanotechnol. and materials science. In this respect, the incorporation of such compds. into thin ordered films appears to be an important issue. One of the most widely pursued approaches to structurally ordered dendrimer assemblies was the prepn. of Langmuir films at the air-water interface. We report on the case of a diblock globular fullerene-based dendrimer and show that peripheral substitution of the dendrimer with hydrophobic chains on one hemisphere and hydrophilic groups on the other provides the required hydrophobic/hydrophilic balance allowing the formation of stable Langmuir films. A second approach was to consider the case of fullerene contg. dendrimers terminated by mesogenic groups such as cyanobiphenyl subunits. Whatever the generation is, up to the fourth one, all these compds. exhibit a well-defined liq. cryst. smectic A phase. The mol. organization within the smectic layers is monolayered or bilayered depending on the generation. For the smallest dendrimers, the organization is mainly governed by the size of the fullerene moiety, whereas for the higher ones, it is governed by the interactions between the terminal mesogenic groups. These two approaches appear particularly interesting for functional groups such as fullerenes, which are not well adapted to be organized in nanoscale architectures. The present study shows that fullerenes can indeed be introduced into different types of ordered structure when they were chem. adequately modified. 3',3''-(Methanoxymethano[1,3]benzenomethanoxymethano)-3'H,3''H-dicyclop ropa[1,9:3,15][5,6]fullerene-C60-Ih-3',3''-dicarboxylic acid. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    Amphiphilic fullerene-cholesterol derivatives: synthesis and preparation of Langmuir and Langmuir-Blodgett films
    (2001)
    Felder, Delphine
    ;
    Carreon, Maria Del Pilar
    ;
    Gallani, Jean-Louis
    ;
    Guillon, Daniel
    ;
    Nierengarten, Jean-Francois
    ;
    Chuard, Thierry
    ;
    Deschenaux, Robert 
    Amphiphilic fullerene bis-adducts 11 and 14 contg. two and four cholesterol moieties, resp., were prepd. starting from the corresponding bis-malonate derivs. In a systematic study, their spreading behavior at the air-H2O interface was compared to that of bis-adduct 6 with no polar head-group. Compared to 6, for which some three-dimensional aggregation occurs, the polar head-group in 11 and 14 is responsible for an attractive interaction with the aq. subphase, forcing the mols. towards the H2O surface into a two-dimensional arrangement. Even if homogeneous Langmuir films were obtained with both 11 and 14, only the films of 14 show a reversible compression/expansion behavior. This suggests that, by increasing the no. of cholesterol subunits, the encapsulation of the C-sphere in its addend is more efficient, thus preventing fullerene-fullerene interactions and aggregation phenomena. The Langmuir films of 11 and 14 were also efficiently transferred onto hydrophilic quartz slides, yielding Langmuir-Blodgett films. [on SciFinder(R)]
  • Publication
    Accès libre
    Amphiphilic Fullerene-Cholesterol Derivatives: Synthesis and Preparation of Langmuir and Langmuir-Blodgett Films
    (2001)
    Felder, Delphine
    ;
    Carreón, Maria del Pilar
    ;
    Gallani, Jean-Louis
    ;
    Guillon, Daniel
    ;
    Nierengarten, Jean-François
    ;
    Chuard, Thierry
    ;
    Deschenaux, Robert 
    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 aggregation occurs, the polar head-group in 11 and 14 is responsible for an attractive interaction with the aqueous subphase, forcing the molecules towards the water surface into a two-dimensional arrangement. Even if homogeneous Langmuir films were obtained with both 11 and 14, only the films of 14 show a reversible compression/expansion behavior. This suggests that, by increasing the number of cholesterol subunits, the encapsulation of the C-sphere in its addend is more efficient, thus preventing fullerene-fullerene interactions and aggregation phenomena. The Langmuir films of 11 and 14 were also efficiently transferred onto hydrophilic quartz slides, yielding Langmuir-Blodgett films.