Soft, Wet-Chemical Synthesis of Metastable Superparamagnetic Hexagonal Close-Packed Nickel Nanoparticles in Different Ionic Liquids.

The microwave-induced decomposition of bis{N,N'-diisopropylacetamidinate}nickel(II) [Ni{MeC(NiPr) } ] or bis(1,5-cyclooctadiene)nickel(0) [Ni(COD) ] in imidazolium-, pyridinium-, or thiophenium-based ionic liquids (ILs) with different anions (tetrafluoroborate, [BF ] , hexafluorophosphate, [PF ] , and bis(trifluoromethylsulfonyl)imide, [NTf ] ) yields small, uniform nickel nanoparticles (Ni NPs), which are stable in the absence of capping ligands (surfactants) for more than eight weeks. The soft, wet-chemical synthesis yields the metastable Ni hexagonal close-packed (hcp) and not the stable Ni face-centered cubic (fcc) phase. The size of the nickel nanoparticles increases with the molecular volume of the used anions from about 5 nm for [BF ] to ≈10 nm for [NTf ] (with 1-alkyl-3-methyl-imidazolium cations).

Properties of new magnetic surfactants.

This Article describes the synthesis and detailed characterization of a new set of magnetic surfactants containing lanthanide metal counterions. SQUID magnetometry has been used to elucidate the magnetic phase behavior, and small-angle neutron scattering (SANS) provides evidence of micellar aggregation in aqueous media. This study also reveals that for cationic surfactants in aqueous systems there appears to be no significant increase in magnetic susceptibility after micellization.

Contrasting macrophage activation by fine and ultrafine titanium dioxide particles is associated with different uptake mechanisms.

Inhalation of (nano)particles may lead to pulmonary inflammation. However, the precise mechanisms of particle uptake and generation of inflammatory mediators by alveolar macrophages (AM) are still poorly understood. The aim of this study was to investigate the interactions between particles and AM and their associated pro-inflammatory effects in relation to particle size and physico-chemical properties.

Water-soluble superparamagnetic magnetite nanoparticles with biocompatible coating for enhanced magnetic resonance imaging.

Ultrasmall superparamagnetic Fe(3)O(4) nanoparticles (USIRONs) were synthesized by a novel, easily scalable chemical reduction of colloidal iron hydroxide under hydrothermal conditions. The average crystallite size (5.1 ± 0.