Elaboration and rheological characterization of nanocomposite hydrogels containing C60 fullerene nanoplatelets.

Nanocomposite hydrogels were elaborated that consisted of a physical network formed by an amphiphilic polymer in which C60 fullerene nanoplatelets were embedded. Characterization showed that the nanoplatelets within the polymer network were aggregated. The presence of these nanoplatelets led to an increase of the shear modulus of the hydrogels, that cannot be explained by a filler effect alone. The nanocomposite gels displayed similar rheological behavior, both in linear and non-linear domains, as neat hydrogels at higher polymer concentrations. We suggest that the particles reinforced the gels by forming additional connections between the polymer chains.

Self-Assembly in water of C60 fullerene into isotropic nanoparticles or nanoplatelets mediated by a cationic amphiphilic polymer.

HYPOTHESIS: To disperse high concentration of C60 fullerene in water, we propose to use an emulsification-evaporation process in the presence of an amphiphilic polymer whose chemical structure has been chosen for inducing specific interaction with fullerene The viscosity enhancement provided by self-assembly of the amphiphilic polymers in water should result in high stability of the suspensions. The organic solvent has also to been chosen so as to maximize the initial fullerene concentration. EXPERIMENTS: The concentrations of polymer and fullerene, the solvent type and the volume fraction of the organic phase have been varied. Their influence on the concentration of the fullerene dispersions and on the size and shape of the resulting nanoparticles have been investigated by UV-Visible spectroscopy, light scattering and cryo-transmission electron microscopy experiments. FINDINGS: The resulting nanoparticles consist of aggregates of C60 fullerene stabilized by the cationic polymer with morphologies/sizes tunable through fullerene and polymer concentration. At high fullerene concentration, nanoplatelets are obtained that consist in thin 2D nanocrystals. Their suspensions are very stable with time due to the viscosity of the dispersing aqueous medium. The concentration of fullerene nanoparticles dispersed in water is as high as 8 g/L which corresponds to an upper limit that has never been reached so far.

Synthesis and self-assembly of a penta[60]fullerene bearing benzo[ghi]perylenetriimide units.

A benzo[ghi]perylenetriimide (BPTI) derivative bearing a terminal azido group on the expanded π-conjugated backbone has been synthesized and characterized. This promising photo- and electroactive BPTI motif has been used to obtain an original penta(organo)fullerene as a promising multi-electron acceptor system. Our studies show its self-assembly resulting from aggregation via π-π stacking interaction in solution and in the solid state.

An original self-assembly using a tetrathiafulvalene-based molecular clip for the recognition of fullerene C60.

A glycoluril-based molecular clip incorporating two tetrathiafulvalene (TTF) sidewalls has been synthesized using a straightforward Diels-Alder synthetic route and its ability to self-assemble with fullerene C60 in a 2 : 1 stoichiometry has been demonstrated in solution.

Syntheses via a direct arylation method of push-pull molecules based on triphenylamine and 3-cyano-4-hexyloxythiophene moieties.

Synthetic access to new push-pull molecules based on 3-cyano-4-hexyloxythiophene and triphenylamine moieties is presented herein using a clean methodology. The key step involves a direct heteroarylation coupling reaction in the presence of a homogeneous or heterogeneous [Pd] catalyst followed by Knoevenagel condensation performed in ethanol as a solvent. Structure-electronic property relationships of the new molecular materials are discussed and then their use as donors in bilayer planar heterojunction solar cells is investigated.

New Penta(tetrathiafulvalenyl)[60]fullerenes for Supramolecular Materials.

New penta(organo)fullerenes donor-acceptor systems bearing five tetrathiafulvalene recognition units have been synthesized to promote self-assemblies similar in appearance to shuttlecocks nested into each other thanks to the conical host cavity created around the fullerene together with the π-π and electronic interactions.

Ionic liquid supported organotin reagents to prepare molecular imaging and therapy agents.

Efficiency of ionic liquid supported organotin reagents in halodemetalation reaction has been investigated. High radiochemical yields of astatinated and iodinated compounds have been obtained using simple work-up procedure. This methodology represents a straightforward approach for the preparation of molecular imaging and therapy agents in nuclear medicine.

Glycoluril-tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests.

Glycoluril-based molecular clips incorporating tetrathiafulvalene (TTF) sidewalls have been synthesized through different strategies with the aim of investigating the effect of electrochemical and spatial properties for binding neutral accepting guests. We have in particular focused our study on the spacer extension in order to tune the intramolecular TTF···TTF distance within the clip and, consequently, the redox behavior of the receptor. Carried out at different concentrations in solution, electrochemical and spectroelectrochemical experiments provide evidence of mixed-valence and/or π-dimer intermolecular interactions between TTF units from two closed clips. The stepwise oxidation of each molecular clip involves an electrochemical mechanism with three one-electron processes and two charge-coupled chemical reactions, a scheme which is supported by electrochemical simulations. The fine-tunable π-donating ability of the TTF units and the cavity size allow to control binding interaction towards a strong electron acceptor such as tetrafluorotetracyanoquinodimethane (F4-TCNQ) or a weaker electron acceptor such as 1,3-dinitrobenzene (m-DNB).

Fused glycoluril-tetrathiafulvalene molecular clips as receptors for neutral electron acceptor guests.

Glycoluril-based molecular clips incorporating tetrathiafulvalene (TTF) sidewalls have been synthesized, and the efficient binding ability in solution of this host architecture toward m-dinitrobenzene through donor-acceptor interaction has been demonstrated.

Synthesis of novel derivatives of murrayafoline A and their inhibitory effect on LPS-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells.

A series of N-substituted-1,2,3-triazole murrayafoline A derivatives were successfully synthesized using click azide-alkyne Huisgen cycloaddition reaction between 1-methoxy-3-methyl-9-(3-azido)-propyl-9H-carbazole and substituted alkynes. Their chemical structures were confirmed by (1)H, (13)C NMR and HR-ESI-MS spectral data. In addition, the interested effects on LPS-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells of synthetic murrayafoline A derivatives were also investigated. Our results indicated that murrayafoline A derivatives containing 1,2,3-triazole nucleus potentially possessed anti-inflammatory action through inhibiting production of IL-6, IL-12 p40 and TNF-α.

Asymmetric synthesis of cyclohexene nucleoside analogues.

The asymmetric synthesis of novel cyclohexene nucleoside analogues 12 and 15 is described. An enantiospecific Diels-Alder reaction between (E,E)-diene 2 and (+)-5-(d-mentyloxy)-2(5H)-furanone 3 provided the cycloadduct isomer 4. Three additional steps yielded amine 8 allowing the constructions of the thymine and adenine moieties to afford intermediates 11 and 14, respectively. Amination or cyclization and removal of the protecting groups occurred in one step in the presence of ammonia, giving the target six-membered ring nucleosides.

Solvent-free direct reductive amination by catalytic use of an organotin reagent incorporated on an ionic liquid.

An organotin reagent supported on an ionic liquid was used as a highly effective catalyst (down to 0.1 mol%) for the direct reductive amination of aldehydes and ketones using PhSiH3; this solvent-free method facilitates purification of the products, thus minimizing the contamination by tin.

Preparation and characterization of second order non-linear optical properties of new "push-pull" platinum complexes.

In this contribution, we report the synthesis and characterization of the second order non-linear properties of a series of unconventional terpyridyl and dipyridylphenyl platinum complexes. These new platinum complexes consist of a tridentate ligand substituted by a high electron acceptor, and a chloro or an arylacetylide ligand. The hyper-Rayleigh scattering measurements reveal that these complexes display large quadratic hyperpolarizabilities reaching a dynamic value of 1460 x 10(-30) at 1064 nm esu for the best complex. This investigation also demonstrates that cyclometalated dipyridylphenyl platinum complexes greatly exhibit enhanced first hyperpolarizability with respect to analogous terpyridyl complexes.

The ground-state rotational spectrum and molecular geometry of ethynylstannane.

The ground-state rotational spectra of 24 isotopomers of ethynylstannane have been observed by pulsed-jet, Fourier-transform microwave spectroscopy. The spectroscopic constants, B(0,)D(J) and D(JK) are reported for symmetric-top isotopomers H(3)(n)Sn(12)C(12)CH, where n = 116, 117, 118, 119, 120, 122 and 124, D(3)(n)Sn(12)C(12)CH, where n = 116, 118, 120, 122 and 124, H(3)(n)Sn(13)C(12) CH and H(3)(n)Sn(12)C(13)CH , where n = 116,118 and 120, and H(3)(n)Sn(12)C(12)CD, where n = 116, 118 and 120. In addition, the values of A(0), B(0), C(0), Delta(J) and Delta(JK) were obtained for the three asymmetric-top isotopomers DH(2)(n)Sn(12)C(12)CH, where n = 116, 118 and 120. Hyperfine structure was resolved and assigned in the transitions of the isotopomers H(3)(n)SnCCD, where n = 116, 118 and 120, and in the isotopomers H(3)(117)SnCCH and H(3)(119)SnCCH. In the former group, the hyperfine structure arises from D nuclear quadrupole coupling while in the latter group its origin lies in the spin-rotation coupling of the I = 1/2 Sn nuclear spin to the rotational motion. For these isotopomers, D nuclear quadrupole and spin-rotation coupling constants are determined where appropriate. The rotational constants obtained for the 24 isotopomers of H(3)SnCCH were used to obtain the following types of molecular geometry for ethynylstannane: r(0), r(s), and r(m).