Ruthenium nanoparticles of controlled size have been prepared by decomposition of the organometallic precursor Ru(cod)(cot) (cod = 1,5‐cyclooctadiene, cot = 1,3,5‐cyclooctatriene) under an H2 atmosphere in either a pure alcohol or an alcohol/THF mixture as solvent and in the absence of further stabilizer. The particles were characterized by transmission electron microscopy (TEM), high‐resolution electron microscopy (HREM), X‐ray diffraction (XRD), wide‐angle X‐ray scattering (WAXS), and X‐ray photoelectron spectroscopy (XPS). The colloidal solutions are stable for long periods of time, in some cases longer than one year. TEM images reveal in most cases the presence of polycrystalline sponge‐like particles of regular spherical shape and homogeneous size or, in some cases, the presence of isolated and well‐dispersed monocrystalline particles, depending upon the alkyl chain length of the alcohol used. In all cases the size distributions are relatively narrow. WAXS and XRD analyses indicate the exclusive presence of hexagonal close‐packed (hcp) ruthenium in these materials. The size of the particles can be controlled by adjusting the reaction temperature or the composition of the solvent mixture. In case of MeOH/THF mixtures, a linear correlation was established between the solvent composition and the size of the particles in the range of 4–85 nm. In the absence of stirring, small individual monocrystalline Ru particles are formed inside superstructures that assemble in some cases into monolayers. Finally, these materials are promising in catalytic hydrogenation of arenes under mild conditions.

Soluble ruthenium nanoparticles of uniform size (see picture) with a porous spongelike structure were obtained by the reaction of [Ru(C(8)H(10))(C(8)H(12))] with H(2) in methanol or THF/methanol. The particle size can be controlled in the range 15-100 nm by varying the MeOH/THF ratio. The particles catalyze benzene hydrogenation without modification of their size or structure. Their formation is proposed to occur in the droplets of a nanosized emulsion, which act as nanoreactors.

A new approach to one-dimensionally organize the quantum dot Au 55 (PPh 3 ) 12 Cl 6 is described by using poly(vinyl-pyrrolidone) (PVP) molecules as templates. AFM investigations indicate chemisorption of the nanoclusters at the surface of the polymers. Using Langmuir−Blodgett techniques, networks of cluster-loaded polymer chains on mica or silicon are generated. The pattern of the networks can be designed from widely distributed but often interconnecting filaments, up to almost densely packed structures, depending on the surface pressure. Those networks are rigid enough to be transferred from the water surface onto solid substrates without degradation. Bare PVP molecules do not give comparable networks under equivalent conditions, indicating that the nanoclusters act as junctions between the chains.