Use of ionic liquids in sol-gel; ionogels and applications

International audienceThe current strong interest in ionic liquids is motivated by their unique combination of properties such as negligible vapour pressure, thermal stability, non-flammability, high ionic conductivity and wide electrochemical stability window. The first part of this short review deals with all the specific aspects of sol-gel in the presence of ionic liquid, which can act as drying control chemical additive, catalyst, porogenous agent and solvent or co-solvent. The second part is devoted to the properties of the gels in which the ionic liquid is kept confined (ionogels) and their applications as electrolyte membranes, optical devices, catalysts and sensors

Stability and solid-state polymerization reactivity of imidazolyl- and benzimidazolyl-substituted diacetylenes: pivotal role of lattice water

International audience1,6-Bis(1-imidazolyl)-2,4-hexadiyne (1) and1,6-bis(1-benzimidazolyl)-2,4-hexadiyne (5) have beenpreparedby a novel method that consists in refluxing excess imidazole and benzimidazole with 2,4-hexadiyne-1,6-diol bis(p-toluenesulfonate),pTS (3). This procedure is a viable alternative to the widely used Hay coupling protocol in case the target diyne possesses substituents capable of deactivating the copper catalyst by complexation. Diyne1crystallizes as a hydrate,1?H2O(2). For this compound, water is essential toachieve a crystalline material, and attempts to obtain crystals without included solvent were unsuccessful. In the structure of2, the organic fragments organize around the water molecule and interact with it through a dense network of hydrogen bonds. The CMC-CMC moieties are not oriented suitably for topochemical polymerization, and when trying to alter the organizationof the crystal by heating so as to induce polymerization, water is lost in an abrupt fashion that leads to instantaneous decomposition into polyaromatic-like species. Similar results were observed when water was removedin vacuo at room temperature. The benzimidazole-containing compound can be crystallized with water molecules (4)orwithout(5). X-ray crystallography shows that the structure of 5is organized by numerous C-H...N, C-H...p,andimidazolyl...imidazolyl p-p interactions. The diacetylene molecules almost have the right arrangement for topochemical polymerization, withpossibly reactingCMC-CMC fragments not beingparallel, a rare situation indiacetylene chemistry. Yet, experiments showthat topochemical polymerizationdoes not occur. Incorporationofwater in the lattice of5leads toa solvate that is topochemically reactive. Unlike2, however, water molecules in 4are not isolated but are organized as ribbons. Spectroscopic characterization of the polymer of4indicates that it is a blue phase polymer, with water coordinated to it. This study shows that it is possible to use water, and more generally solvent molecules, to transform a nonreactive diacetylene into a reactive one, even though this approach is less predictable than the cocrystal approach developed by Fowler, Lauher, and Goroff. The solvate approach is simple to implement, quite versatile because of the large rangeof solvents available, andonedoes not face theproblemof having to remove the host in case one needs to recover the polymer. Previous studies describing a similar approach are scarce

Solides organiques-inorganiques organisés (dérivés organophosphorés de l'aluminium)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Utilisation d'agents de couplage organophosphorés pour la préparation d'hybrides organiques-inorganiques à base d'oxydes métalliques

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Ionic Liquids 2014 and Selected Papers from ILMAT 2013: Highlighting the Ever-Growing Potential of Ionic Liquids

Ionic Liquids (ILs) are arguably among the most intensely researched areas in today’s natural sciences, especially the chemistry, physics, and materials sciences fields. The high promise of ILs for essentially all fields of science, engineering, and technology has also led to a sprouting of national and international meetings focusing on ILs and their use and application. Probably, the largest IL meeting is the Conference on Ionic Liquids (COIL) conference, now going into its 6th edition, to take place in Korea in 2015.[...

Différentes stratégies d'auto-assemblage de dérivés diacétyléniques porteurs d'hétérocycles azotés aromatiques (application à la synthèse de matériaux)

Les polydiacétylènes sont des polymères p-conjugués, obtenus par polymérisation topochimique à l'état solide de motifs diacétyléniques, sous l'effet d'un stimulus thermique ou photochimique. Depuis leur découverte en 1969 par Wegner, les polydiacétylènes ont fait l'objet de nombreux travaux de recherche. Ces travaux ont consisté tout d'abord à élucider le mécanisme de polymérisation, puis à étudier les diverses propriétés photophysiques, optiques, et électroniques des polymères. Néanmoins, la plupart des diacétylènes étudiés ne possédaient pas de substituants susceptibles d'être modifiés chimiquement. Le premier chapitre de cette thèse décrit la synthèse de nouvelles molécules diacétyléniques symétriques comportant des groupements azoles, et l'étude de leur polymérisation à l'état solide. La modification de l'organisation des motifs diacétyléniques.par interaction avec des molécules capables de former des liaisons hydrogène, et l'incorporation de ces motifs dans des matériaux hybrides organiques-inorganiques de type,. MOF ont également été examinées.Dans le deuxième chapitre, nous nous sommes intéressés aux composés diacétyléniques dicationiques fonctionnalisés par des groupements triéthylammoniums, imidazoliums et benzimidazoliums. La synthèse de ces composés, leur caractérisation spectroscopique, et cristallographique, ainsi que l'étude de leur réactivité thermique et photochimique ont été réalisées.Dans le troisième chapitre, nous proposons une méthode directe de préparation de carbone dopé à l'azote par pyrolyse des molécules diacétyléniques neutres, ainsi que la synthèse de carbone mésoporeux en présence d'un sel métallique. Un autre aspect de ce chapitre est l'optimisation des teneurs en azote en utilisant comme précurseurs les composés diacétyléniques dicationiques, associés à des anions riches en azote, notamment l'anion dicyanamide [dca] et tricyanométhide [tcm].Diacetylenes (DA) are unusual molecules owing to their ability to polymerize in the solid state. Such a polymerization is triggered off thermally or photochemicaly, and leads to the formation of enyne structures. Since their discovery in 1969 by Wegner, polydiacetylenes (PDA) have been the focus of much attention. Initially, many studies were devoted to elucidating the mechanism of polymerization, then assessment of the diverse photophysical, optical, and electronic properties of the polymers became the main goal. Yet, the vast majority of the DA that were studied did not possess substituents that could be modified chemicallyThe first chapter describes the synthesis of new symmetrical diacetylenic molecules functionalized with azole substituents and the study of the polymerization of these compounds in the solid state. Then, we present the modification of the organization of these diacetylenes by the interaction with molecules capable of forming hydrogen bonds, and the use of these molecules as ligands for the synthesis of Metal Organic Frameworks (MOF).The second chapter is devoted to the synthesis, characterization and crystallographic study of ionic diacetylenic compounds bearing triethylammonium, imidazolium and benzimidazolium groups. The photochemical and thermal behaviors of these DA have been tested.In the third chapter, we propose a straightforward route to N-doped graphitic carbon by direct pyrolysis of neutral diacetylenic precursors, and investigate the possibility of forming porous materials by adding a metal salt as a catalyst. Furthermore, another aspect of this chapter was to optimize the nitrogen content of these materials by using dicationic DA with N-rich anions, e.g. dicyanamide [dca] and tricyanomethide [tcm].MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF