Synthese et reactivite des F-alkyl sulfures et sulfones actives

In this paper we report syntheses of F-alkyl compounds such as R_FC₂H₄S(O)_nCH₂Z (with n=0,2 and Z=H,Ø(C₆H₅),COØ,COOEt,COCH₃,CN). Using the carbanionic reactivity of these compounds, we would like to use them as precursors of surfactants, grafting hydrophilic functions on the carbons α or α′ to the sulfur atom. The compounds were not very reactive. Alkylation or acylation on this site could only be obtained with a ‘pseudo malonic’ CH₂ (R_FC₂H₄SO₂CH₂Z with Z=COØ, COOEt,COCH₃,CN). Only methyl iodide and acetyl chloride led to positive results.     

Sur un théorème de comparaison en algèbre homologique Applications aux fibrations

Sans résumé     

Etudes en série indolique: VII Synthèse de nouveaux pyridocarbazoles obtenus par photocyclisation de (β-indolyl)-1 (pyridyl)-2 acrylonitriles

The photocyclization of 2-(3-indolyl)-3-(3-pyridyl)propenenitrile yields pyrido[a]carbazoles which represent intermediates to the original pentacyclic skeletons; the new indolopyridoquinoxaline 8 constitutes a structural analog of the alkaloid eburnamonin.     

Giant brainlike aggregates from new fluorocarbon/hydrocarbon hybrid cationic surfactants

A rapid synthetic procedure in two steps from perfluoroalkylethyl iodide derivatives led to 18 novel ammonium type hybrid surfactants of the general formula: R(F)(CH(2))(2)S(CH(2))(2)N(+)(CH(3))(2)R(H)Br(-) (R(F) = C(4)F(9), C(6)F(13), C(8)F(17); R(H) = C(4)H(9), C(6)H(13), C(8)H(17), C(10)H(21), C(12)H(25), C(14)H(29)). These hybrid surfactants exhibited very low surface tension (from 16 to 25 mN/m) as well as low critical micellar concentration until 1.5 × 10(-5) mol/L. A special focus was made on aggregation phenomenon as giant multilamellar "brainlike" vesicles were observed via cryogenic scanning electron microscopy (cryoSEM) and transmission electron microscopy (TEM; with a contrast agent) suggesting a high encapsulation ability and a very important specific surface of these particular organizations.     

Synthese et application de nouveaux sulfures a chaine perfluoree

Metallation of thiols R_FC₂H₄SH followed by alkylation with iodides R′_FC₂H₄I leads either to symmetrical or to unsymmetrical sulphides R_FC₂H₄SC₂H₄R′_F (with R_F=R′_F or R_F ≠ R′_F). All compounds obtained are good solvents of gases (particularly O₂, CO, CO₂, N₂).This property allows their application as biological carriers of dissolved gases.     

Differential and Complex Geometry of Two-Dimensional Noncommutative Tori

We analyze in detail projective modules over two-dimensional noncommutative tori and complex structures on these modules. We concentrate our attention on properties of holomorphic vectors in these modules; the theory of these vectors generalizes the theory of theta-functions. The paper is self-contained; it can be used also as an introduction to the theory of noncommutative spaces with simplest space of this kind thoroughly analyzed as a basic example.     

Influence of spacer in the formation of nanorings by templateless electropolymerization

In this original work, we want to control the shape of the resulting porous structures by templateless electropolymerization, by adjusting the spacer (flexible alkyl chains or rigid aromatic groups) between thieno[3,4-b]thiophene and carbazole used as the monomer and the substituent, respectively. A huge change is especially observed from ribbon-like structures to nanorings as the alkyl spacer increases. The presence of a significant amount of water is necessary for the formation of these porous structures because it allows releasing a high amount of gas bubbles. The size and number of nanorings are dependent on both the alkyl spacer and electrochemical parameters such as the number of deposition scans. These surfaces could be used in the future in various potential applications such as in water harvesting, oil/water separation membranes, optical devices, sensors or photocatalysis.     

PFC's biological carriers of gases: synthesis of F-alkylated sulfides and related compounds

New compounds (R_FC₂H₄SC₂H₄R′_F with R_F=R′_F ou RF≠R′_F), corresponding sulfoxides and sulfones, and related compounds, were prepared, purified and characterized to investigate further the relationship between chemical structure and their usefulness as components of artificial blood.The Sulfides are chemically inert; only oxidations leading to sulfoxides and sulfones under very hard conditions (concentrated H₂O₂, heating) were performed.The oxygen carrier capability was leasured by two ways: —Determination of magnetic susceptibility by NMR using two different configuration spectrometers. — Gas chromatography.Results of the two methods are in good agreement and the same as the best products used as artificial blood substitutes : O₂(40% vol., NMR and G.C.), N₂(35% vol., G.C.), CO₂(150ml/100ml G.C.). Other avantages of such products : — Synthesis quite simple, specific univocal chemical routes. -Series of homologous compounds to permit optimisation of vapor pressure and viscosity on which depends the most important parameters of emulsions - Starting materials commercially available; -Quite quantitative yields. News series of related compounds were obtained, modifying basic structure in the former step of the synthesis by chemical routes.