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Highly crystalline epitaxial Ba0.8Sr0.2TiO3 (BST) thin-films are grown on (001)-oriented LaNiO3-buffered LaAlO3 substrates by pulsed laser irradiation of solution derived bariumzirconium-titanium precursor layers using a UV Nd:YAG laser source at atmospheric conditions. The structural analyses of the obtained films, studied by X-ray diffractometry and transmission electron microscopy, demonstrate that laser processing allows the growth of tens of nm-thick BST epitaxial films with crystalline structure similar to that of films obtained through conventional thermal annealing methods. However, the fast pulsed nature of the laser employed leads to crystallization kinetic evolution orders of magnitude faster than in thermal treatments. The combination of specific photothermal and photochemical mechanisms is the main responsible for the ultrafast epitaxial laser-induced crystallization. Piezoresponse microscopy measurements demonstrate equivalent ferroelectric behavior in laser and thermally annealed films, being the piezoelectric constant ~25 pm V-1. [ABSTRACT FROM AUTHOR]

We describe the stabilization studies of new palladium nanoparticles (Pd NPs) with a family of hybrid ligands. For this purpose, two new N,O-hybrid pyrazole derived ligands, as well as other previously reported, have been used as NP stabilizing agents following an organometallic approach. A comparison with corresponding palladium complexes has been carried out. We have also studied the superstructures formed by the agglomeration of NPs. To evaluate the scope of the system, different parameters have been studied such as the structure of the ligand, the ligand/metal ratio, the nature of the solvent, the concentration and the reaction time. The colloidal materials resulting from the different syntheses were all characterized by IR, transmission electron microscopy techniques at low or high resolution (TEM and HR-TEM), and scanning electron microscopy (SEM-FEG). All these observations have allowed us to better understand the coordination modes of the different ligands onto the surface of the NPs.

The preparation of Ru(0) nanoclusters stabilized by 3-aminopropyltriethoxysilane and their characterization by a combination of complementary techniques are described. These new Ru(0) nanoclusters provide high activity and unprecedented reusability as a heterogeneous catalyst in the dehydrogenation of dimethylamine-borane.

The synthesis of palladium, platinum and ruthenium nanoparticles stabilized by azamacrocycles bearing polyoxyethylenated chains has been achieved by decomposition of the corresponding organometallic precursors (Pd(dba)(2), Pt(2)(dba)(3) and Ru(COD)(COT)) under dihydrogen atmosphere, whereas gold and rhodium nanoparticles have been obtained in the presence of these ligands by reduction of HAuCl(4) and RhCl(3), respectively. The metal nanoparticles were characterized by several techniques including IR, NMR, UV-vis, HRTEM, ED, and elemental analysis. The Pd nanoparticles have been used as recoverable catalyst in Suzuki cross-coupling in aqueous medium.

Iron nanoparticles prepared by reducing FeCl(3) with three equivalents of EtMgCl in THF are effective catalysts for the hydrogenation of alkenes and alkynes under moderate conditions.

Generations 1 to 3 of dendrimers ended by water-soluble phosphines are synthesized and their ruthenium complexes are used as catalysts in aqueous media; a slightly positive dendritic effect on the regioselectivity is observed for hydration of alkynes and a large positive dendritic effect is observed in the biphasic (water/heptane) catalysed isomerisation of allylic alcohols to ketones where the products are easily isolated and the catalyst can be reused several times, even the first generation.

The immobilization of phosphine-free perfluoro-tagged palladium nanoparticles Pd-1 on fluorous silica gel (FSG) and their utilization in the Heck reaction have been investigated. High yields of vinylic substitution products have been obtained. Recycling studies have shown that the solid-supported palladium catalyst can be readily recovered and reused several times without significant loss of activity. Reactions and recovery of the solid-supported palladium catalyst system can be carried out in the presence of air, without any particular precaution.