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Azamacrocycles bearing four arylsulfonyl or arylsulfinyl pendant arms have been synthesised with good yields through nucleophilic addition of 1,4,8,11-tetraazacyclotetradecane (cyclam) to phenylvinylsulfone, phenylvinylsulfoxide or (R)-tolylvinylsulfoxide in isopropanol/water media. The crystal structure of the tetraethylsulfonylphenyl substituted macrocycle has been determined by X-ray crystallography. Preliminary studies of the coordination properties of these functionalised macrocyles towards Cu(II) and Eu(III) indicate that pendant sulfoxide groups act as oxygen donor coordinating groups.

Metal-complexing nanoparticles, with average diameters ranging from 15 to 25 nm, are prepared using a two-step procedure: synthesis of reactive nanoparticles followed by post-functionalisation with a selective macrocyclic ligand, cyclam (tetraazacyclotetradecane). The starting nanoparticles, containing benzylhalide reactive groups are readily prepared by copolymerisation of vinylbenzylchloride in ternary oil-in-water microemulsions stabilized by a cationic surfactant (dodecyltrimethyl ammonium bromide). Elemental analyses of the polymer reveals that exchange of chlorine for bromine as well as hydrolysis of chloromethyl residues occur within the reaction medium, the rate of both side reactions being dependent upon the experimental conditions. The overall content of reactive chloro- and bromobenzyl moieties range from 0.7 to 1.1 mmol g–1. Reaction of cyclam, performed directly in the aqueous suspensions, gives rise to stable suspensions of functionalised nanoparticles containing 0.2 to 0.3 mmol ligand g–1. Spectrophotometric measurements show that these cyclam post-functionalized nanoparticles exhibit a ‘solution-like’ complexation behaviour thus demonstrating remarkable ligand accessibility. To cite this article: C. Larpent et al., C. R. Chimie 6 (2003).

Time-resolved laser-induced fluorescence (TRLIF) has been used for interaction studies between europium(III) used as a fluorescent probe and a new micellar system (TAC8) of a “diblock” surfactant–cage molecule containing a cage (cyclam) as a complexation part linked to a sugar-based surfactant part. The effect of each constituent (cage and surfactant unit) as well the complete molecule on the europium fluorescence have been studied. By using the hypersensitive transition of europium, it was shown that the separate constituents, e.g. cyclam and surfactant, had little effect. On the other hand, the complexation constant between europium and TAC8 was close to 102 demonstrating that a synergetic effect is achieved with such a diblock surfactant–cage molecule.

Bis-tetraazacyclotetradecanes (bis-cyclam) are readily prepared with fairly good yields in a one step procedure from non-protected cyclam. The synthesis involves a selective addition of cyclam on bis-acrylamides in chloroform in the presence of one equivalent of p-toluenesulfonic acid.

Oil-in-water microemulsions of mixtures of styrene and comonomer are easily prepared using titration methods in the presence of nonionic (NPn) or anionic (SDS) surfactants. Functionalized nanoparticles in the 20–30-nm diameter range bearing chloromethyl, active-ester, acid or pyridyl surface end-groups are prepared by polymerization of microemulsions containing mixture of styrene (St) and, respectively, vinylbenzylchloride (VBC), N -acryloyloxysuccinimide (NHA), methacrylic acid (MA) or vinylpyridine (VP). Reactions of nucleophiles on particles bearing either chloromethyl or active-ester surface end-groups, performed directly in the aqueous suspensions, give rise to a wide range of nanoparticles with various functionalities. The main role of the surfactant on such surface reactions is demonstrated and used to improve the reaction yields.

Microheterogeneous catalytic systems using aqueous suspensions of rhodium particles are proved to be efficient for alkene hydrogenation in biphasic liquid-liquid medium provided that the method of stabilization and the interfacial phenomena are properly chosen and controlled. Aqueous supensions stabilized by specially designed trianionic molecules or by hydrophilic polymer (PVA) have been studied. A series of trisulfonated molecules 1 with modulated solution behaviors (surfactant or hydrotrope) depending on the nature of the substituents has been used to stabilize aqueous suspensions of oxidized (polar) or reduced (non polar) rhodium particles. Stabilization of polar particles occurs whatever the substituents when stabilization of metallic apolar particles requires surfactants bearing a significant lipophilic part. In the former case, highly stable suspensions of rhodium nanoparticles with controlled size are obtained in micellar solutions. Both oxidized and reduced rhodium suspensions efficiently catalyzed octene hydrogenation in liquid-liquid medium and it is established that high activity and possible recovery and recycling of the catalyst can be achieved by the control of interfacial parameter e.g. the interfacial tension. In the same way, common polymer-protected colloidal suspensions of Rh(0) particles are proved to efficiently catalyze hydrogenation in two liquid phases systems provided that optimized amounts of surfactants are added to reduce the interfacial tension without emulsification. From these results a relationship between interfacial tension and catalytic activity in biphasic system is proposed.

Catalytic oxidation of alkanes occurs in reverse (water in oil) microemulsions stabilized by an anionic surfactant (Aerosol OT®). The catalytically active microemulsion is generated by mixing two reverse microemulsions containing respectively an aqueous solution of iron (FeII or FeIII) and an aqueous solution of H2O2 (30%) dispersed in liquid alkanes (continuous oil phase). This microemulsion system is active in the CH bond oxidation of various liquid alkanes (cycloalkanes, decalin, tetralin, alkylbenzenes) into ketones and secondary and tertiary alcohols at room temperature. The selective oxidation of secondary carbons into ketones and tertiary carbons into alcohols is interpreted by the intervention of iron(V) oxene intermediates rather than radical Fenton-type mechanisms. Polynuclear aggregates such as colloidal hydrous ferric oxides generated by hydrolysis within the aqueous microdroplets are assumed to be the catalytically active species. In fact, we demonstrate that previously prepared iron oxide colloids (Fe2O3 and FeOOH) similarly catalyze the oxidation of alkanes with hydrogen peroxide in reverse microemulsions. The low interfacial water—hydrocarbon tension and the very high interfacial area in liquid—liquid dispersions greatly favour the catalytic process.

Optically pure (S) ethyl-2-hexan-1-ol (S) 4 is prepared for the first time from (S) ethyl-2-hexanoic acid. Nucleophilic addition of sodium bisulfite on the bis [(S) ethyl-2-hexyl] maleate gives rise to an equimolar mixture of two optically active sodium bis [(S) ethyl-2-hexyl] sulfosuccinates diastereoisomers. The critical micelle concentration of these new optically active surfactants is almost identical to those of the well known racemic ĺdAerosol OTŕd

PPH 3 reacts with activated alkynes in reverse (water-hydrocarbon) microemulsions giving specifically rise to a mixture of Z and E triphenylvinylphosphonium salts which are readily isolated in good yields.