Karine Heuzé

A very efficient, copper-free palladium catalyst for the Sonogashira reaction with aryl halides

The new complex [Pd[t-Bu2PCH2N(CH2Ph)CH2P t-Bu2](OAc)2] is a very efficient catalyst for the Sonogashira cross-coupling reaction of aryl halides with acetylenes at room temperature, without co-catalyst.

Copper-free, recoverable dendritic Pd catalysts for the Sonogashira reaction

Three generations of bidentate phosphinated Pd(II) dendrimers are efficient catalysts in the absence of copper co-catalyst for the Sonogashira reaction and are, with two cyclohexyl substituents on the phosphorus atoms, recovered by precipitation and re-used.

Dendron-Functionalized Core―Shell Superparamagnetic Nanoparticles: Magnetically Recoverable and Reusable Catalysts for Suzuki C―C Cross-Coupling Reactions

A metallodendron functionalized with dicyclohexyldiphosphino palladium complex was synthesized. The metallodendron was grafted onto core-shell superparamagnetic nanoparticles (gamma-Fe(2)O(3)/polymer, 200-500 nm) to give optimal catalytic reactivity in cross-coupling reactions. The grafted nanoparticles were used as recoverable and reusable catalysts for Suzuki C--C cross-coupling reactions. They showed remarkable reactivity towards iodo- and bromoarenes under mild conditions, and unprecedented reactivity towards chloroarenes. On completion of the catalytic reaction, the catalysts were readily recovered by using a simple magnet to attract the superparamagnetic grafted nanoparticles. Catalysts were recovered more than 25 times with almost no discernable loss of reactivity.

Rational Design of Low Molecular Mass Organogelators: Toward a Library of FunctionalN-Acyl-1,ω-Amino Acid Derivatives

N-Acyl amino acids RCONH(CH2 )n COOR1 represent a new family of organogelators that can be obtained in a combinatorial approach from libraries of activated acids and amino acids. The amounts required for gel formation in solvents such as DMF are less than 1 mg mL-1 and the gels formed are very stable. n=5, 7, 10, 12; R=aromatic or aliphatic group; R1 =H or alkali metal (Na).

The crystal chemistry of amide-functionalized ethylenedithiotetrathiafulvalenes: EDT-TTF-CONRR′ (R, R′ = H, Me)

The preparation of ethylenedithiotetrathiafulvalenes (EDT-TTF) directly functionalized on the TTF core with a primary, secondary or tertiary amide or an hydrazide functional group is described. The X-ray crystal structures of EDT-TTF-CO 2 H, EDT-TTF-CONH 2 , EDT-TTF-CONHMe and EDT-TTF-CONMe 2 are reported. The solid state architectures adopted by those functionalized molecules appear to be a compromise between the hydrogen bond requirements of the OH, NH 2 , CH and CO groups, which act as hydrogen bond donor and acceptor, respectively, and the S···S van der Waals interactions of the EDT-TTF moiety. The activation of the hydrogen atom of the TTF core, ortho to the amidic group, enhances its involvement in short C–H···O bonds, giving rise to a characteristic chelating R 2 1 (7) motif as observed in the secondary amide, EDT-TTF-CONHMe.

Metallodendritic Grafted Core–Shell γ‐Fe2O3 Nanoparticles Used as Recoverable Catalysts in Suzuki CC Coupling Reactions

The use of dendritic structures for the grafting of core-shell γ-Fe(2)O(3)/polymer 300 nm superparamagnetic nanoparticles (MNPs) has been performed with four metallodendrons that were functionalized with diphosphinopalladium complexes. The catalytic performance of these nanocatalysts was optimized for the Suzuki C-C cross-coupling reaction. These results demonstrated the importance of optimizing the catalytic efficiency of grafted MNPs by optimizing the dendritic structures and the nature of the peripheral phosphine ligands. All of these nanocatalysts showed remarkable reactivity towards bromoarenes and they were recovered and efficiently reused by magnetic separation with almost no loss of reactivity, even after 25 cycles.

Functionalized hydrogen-bonding self-assembled monolayers grafted onto SiO2 substrates.

A novel urea coupling agent possessing a vinyl-terminal group and trimethoxysilyl anchoring group was synthesized and grafted onto SiO(2)/Au substrates. This ureido coupling agent exhibits a good capacity to directly yield homogeneous SAMs with a surface smoothing. Polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS) was used to monitor these SAMs. Indeed, the different functional groups (alkyl chain, urea, and vinyl) of this coupling agent were clearly observed in the PM-IRRAS spectra. Chemical modifications of the terminal function for the covalent immobilization of biomolecules were monitored by PM-IRRAS for the first time. We have demonstrated the successful reactions of the conversion of the vinyl-terminated SAMs successively into SAM-COOH and SAM-NHS without any degradation of the monolayer. The reactivity of activated esters was successfully investigated in order to immobilize the protein A.

Efficient strategy to increase the surface functionalization of core–shell superparamagnetic nanoparticles using dendron grafting

Core–shell γ-Fe2O3/polymer 300 nm superparamagnetic nanoparticles, grafted by fluorescent dendrons using a convergent approach, showed an increase in their surface functionalization compared to grafting using a linear analogue.

Polycarboxylate ethers: The key towards non-toxic TiO2 nanoparticle stabilisation in physiological solutions

Stable, non-agglomerated TiO2 nanoparticle (NP) dispersions are a crucial requirement for an accurate NP dosing in in vitro and in vivo experiments. In this study self-synthesised TiO2 NPs were stabilised in three different cell culture media (DMEM, RPMI, BEGM) with the help of stabilising agents. Cell culture tested stabilisers (bovine serum albumin, fetal bovine serum) were compared to non-tested commercial products which are commonly utilized in the cement industry (Melflux(®) 4930 F, Melpers(®) 4343, Sika(®) ViscoCrete(®)-10110178). For a quantitative evaluation and comparison of the degree of stabilisation, a sedimentation study using UV absorbance spectroscopy was carried out and the agglomerate size was measured via dynamic light scattering. The cytotoxicity of the novel surfactants and stabilised NPs was examined in a head and neck squamous cell carcinoma-derived FaDu cell line and in human mesenchymal stem cells. We successfully stabilised TiO2 NPs with Melflux(®) 4930 F in each cell culture medium, achieving perfect stability over at least one day and agglomerate sizes of less than 100nm, while the cytotoxicity of the NPs was not affected.

Efficient and recyclable dendritic Buchwald-type catalyst for the Suzuki reaction

A Buchwald-type ligand attached to a star-shape molecule was synthesized in high yield, and its catalytic properties for the Suzuki reactions are shown to be excellent (down to 50 ppm with a simple chloroarene) including recovery/re-use of this hexa ligand.