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The convergent synthesis of fluorescent polystyrene core–PAMAM shell nanoparticles in the 15–20 nm diameter range is presented using azido-coated nanoparticles (NPN3) as a clickable platform. The c...

Stable translucent aqueous suspensions of ligand-functionalized nanoparticles, with average diameters ranging from 12 to 20 nm and containing from 0.25 to up to 0.75 mmol of ligand/g, are readily obtained by copolymerization in oil-in-water microemulsions of a polymerizable tetraaza macrocycle, vinylbenzylcyclam (cyclam: 1,4,8,11-tetraazacyclotetradecane). These nanoparticles exhibit a very high selectivity for cupric ions with binding capacities of up to 0.65 mmol of Cu/g as well as a remarkable ligand accessibility, deduced from spectrophotometric titration, with about 75% of the cyclam residues located near the surface for nanoparticles in the 12-13 nm range. Core-shell bimetallic nanoparticles are obtained by cation exchange. The cyclam-functionalized nanoparticles are comparable to high-generation PAMAM dendrimers in their ability to complex metals.

New reactive-surfactants, N-alkylglucosylacrylamides and N-alkylglucosylmethacrylamides, are easily prepared in two steps from glucose without protection. The complete structural analysis of these compounds by 1D and 2D NMR spectroscopy shows the existence of a rotational isomerism that is strongly dependent on the steric hindrance of the carbonyl substituent: whatever the alkyl chain length, both endo and exo rotamers are observed for N-alkylglucosylacrylamides 1 while the endo rotamer is the sole species observed in the case of N-alkylglucosylmethacrylamides 2. For acrylamido derivatives 1, the exo-endo equilibrium is solvent-dependent: the endo isomer is favored in polar nonaqueous solvents (endo-exo isomeric ratio R = 70/30) while the equilibrium is shifted toward the exo rotamer in protic acidic medium (R = 50/50 in water and 80/20 in acidic medium). An intramolecular hydrogen bond is assumed to be responsible for the increased stability of the endo rotamer. Furthermore, for tetra-O-acetylated derivatives the exo rotamer becomes favored in aprotic solvents. Surface tension measurements demonstrate that N-octyl- to -tetradecyl-substituted compounds 1 and 2 are surfactants with critical micelle concentrations ranging from 1.2 x 10(-2) to 1.7 x 10(-5) mol/L.

The polymerization of styrene-in-water microemulsions prepared using polymerizable cosurfactants, such as hydroxyalkyl acrylates or methacrylates, gives rise to stable suspensions of well-defined h...