Low melting mixtures based on beta-cyclodextrin derivatives and N,N '-dimethylurea as solvents for sustainable catalytic processes

International audiencebeta-Cyclodextrin series and N,N'-dimethylurea formed low melting mixtures able to immobilize organometallic species based on sulfonated phosphanes. Hydroformylation and Tsuji-Trost reactions were efficiently performed in these new solvents which led to new recyclable catalytic systems

Experimental and Numerical Approaches of Contact with Friction and Wear in Large Deformation

peer reviewe

«Solvents based on cyclodextrin derivatives and N,N'-dimethylurea for sustainable organometallic catalytic processes»

International audienceno abstrac

«Low-melting mixtures based on N,N’-Dimethylurea/b-cyclodextrins derivatives for homogeneous biphasic catalytic processes»

National audienc

New water-soluble Schiff base ligands based on β-cyclodextrin for aqueous biphasic hydroformylation reaction

International audienc

Rhodium catalyzed hydroformylation of 1-decene in low melting mixtures based on various cyclodextrins and N,N '-dimethylurea

International audienceDifferent low melting mixtures (LMMs) based on N,N'-dimethylurea (DMU) and various cyclodextrin (CD) derivatives were synthetized. The melting point was weakly affected by the size and the chemical modification of CD. By contrast, the chemical modification of CD led to a decrease in viscosity of the LMMs. These mixtures were evaluated as solvent in rhodium-catalyzed hydroformylation reaction of 1-decene. The LMM based on DMU/RAME-beta-CD (70/30) allowed reaching the highest catalytic activity (1980 h(-1)). The influence of several factors was studied and it was established that the conversion increased with the 1-decene solubility and decreased with the LMM viscosit

«Low melting mixtures based on cyclodextrin derivatives and N,N’-dimethylurea as new solvents for biphasic organometallic catalysis»

International audienceno abstrac

Polyoxometalate, Cationic Cluster, and γ-Cyclodextrin: From Primary Interactions to Supramolecular Hybrid Materials

International audienceHerein, we report on a three-component supramolecular hybrid system built from specific recognition processes involving a Dawson-type polyoxometalate (POM), [PWO], a cationic electron-rich cluster [TaBr(HO)], and γ-cyclodextrin (γ-CD). Such materials have been investigated using a bottom-up approach by studying the specific interactions between γ-CD and both types of inorganic units. Their ability to interact has been investigated in the solid state by single-crystal X-ray diffraction (XRD) and in solution using multinuclear NMR methods (including DOSY, EXSY, and COSY), electrospray ionization mass and UV-vis spectroscopies, electrochemistry, and isothermal titration calorimetry experiments. Single-crystal XRD analysis reveals that POM:γ-CD constitutes a highly versatile system which gives aggregates with 1:1, 1:2, and 1:3 stoichiometry. Surprisingly, these arrangements exhibit a common feature wherein the γ-CD moiety interacts with the Dawson-type POMs through its primary face. We present also the first structural model involving an octahedral-type metallic cluster with γ-CD. XRD study reveals that the cationic [TaBr(HO)] ion is closely embedded within two γ-CD units to give a supramolecular ditopic cation, suitable to be used as a linker within extended structure. Solution study demonstrates clearly that pre-associations exist in solution, for which binding constants and thermodynamic parameters have been determined, giving preliminary arguments about the chaotropic nature of the inorganic ions. Finally, both building blocks, i.e., the ditopic supramolecular cation {[TaBr(HO)]@2CD} and the Dawson-type anion, react together to give a three-component, well-ordered hybrid material derived either as a supramolecular hydrogel or single crystals. The solid-state structure shows an unprecedented helicoidal tubular chain resulting from the periodic alternation of POM and supramolecular cation, featuring short hydrogen-bonding contacts between the electron-poor POM and electron-rich cluster. The 1D tubular ionic polymer observed in the single crystals should make it possible to understand the long-range ordering observed within the hydrogel hybrid material. The supramolecular chemical complementarities between the γ-CD-based ditopic cation and POM open a wide scope for the design of hybrid materials that accumulate synergistic functionalities