The new generation of high power fiber lasers presents several benefits for industrial purposes, namely high power with low beam divergence, flexible beam delivery, low maintenance costs, high efficiency and small implantation space. This paper presents preliminary results of weld beads produced on thick X100 pipeline carbon-steel plates with an 8 kW fiber laser. Weld bead geometry was evaluated and transition between conduction and deep penetration welding modes was investigated.
A simple high-yielding method for the preparation of a tetramethylcyclopentadienyl-NHC ligand is described. This ligand has been successfully coordinated to Rh and Ir. A related Cp*-NHC ligand with a -CH(2)CMePh- linker between the Cp* and the NHC is also described, together with its coordination to Rh and Ir. This latter ligand, affords the orthocyclometallation of the phenyl ring yielding a constrained structure in which the ligand is tridentate. All the complexes have been fully characterized and their crystal structures are described. Preliminary catalytic results on the beta-alkylation of secondary alcohols and N-alkylation of aniline with primary alcohols are also reported.
A new pentamethylcyclopentadienyl-functionalized N-heterocyclic carbene ligand (Cp*-NHCMe) has been prepared and coordinated to iridium upon reaction with [Ir(μ-Cl)(cod)]2. The chiral Ir complex is obtained as a racemic mixture of the two possible enantiomers, and its crystal structure is described. The new compound shows high catalytic activity toward transfer hydrogenation, β-alkylation of secondary alcohols with primary alcohols, and amination of primary alcohols.
A set of four different (Cp x -NHC)Mo(CO) 2 I (Cp x =Cp, Cp*, and Cp Bz , NHC=N-heterocyclic carbenes) complexes has been prepared from the one-pot reaction of [MoCl(η 3 -C 3 H 5 )(CO) 2 -(NCMe) 2 ] and the corresponding lithium NHC-cyclopentadienides. The modification of the Cp x -NHC affords a smooth way to tune the stereoelectronic properties of these new molybdenum complexes. These compounds are air stable both in solution and in the solid state. Preliminary studies on the catalytic epoxidation with cis-cyclooctene and TBHP as oxidant show that the activity of the catalysts clearly depends on the nature of the Cp x -NHC ligand. The reaction proceeds smoothly toward epoxide; no diols or any other byproduct was detected along the reaction course.
Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.
Core–shell nanogels are attractive stabilizers and supports for catalytically active metallic nanoparticles. Herein, we present the synthesis and the characterization of a nanostructured well‐defined core–shell nanogel with the ability to stabilize Pd0 nanoparticles in its core. This hybrid nanogel displays a remarkable stability in both the solid state and in solution. This feature allowed its successful application as a catalyst for the Mizoroki–Heck reaction between n‐butyl acrylate and a series of bromo‐ and iodoarenes. The yields spanned from good to excellent, and catalyst recycling could be achieved up to three times without a significant activity loss. Three‐phase tests indicated that the hybrid nanogel acts as a Pd0 nanoreservoir. The catalysis proceeds in a quasihomogeneous fashion as part of the catalytic activity occurs outside the nanogel, which explains the observed limited recyclability.
Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.
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