Polyoxomolybdate‐Stabilized Ru⁰ Nanoparticles Deposited on Mesoporous Silica as Catalysts for Aromatic Hydrogenation

Abstract

We use polyoxometalates as precursors for the preparation of heterogeneous catalysts. In the starting molecular precursor [{Ru(C6Me6)}(2)Mo5O18{Ru(C6Me6)(H2O)}], three ruthenium arene fragments are supported on a formally lacunary Lindqvist-type polyoxomolybdate. This species was introduced by incipient wetness impregnation into the porosity of a SBA-15-type mesoporous silica. The evolution of the system under reducing atmosphere is followed by several methods, such as temperature-programmed reduction (TPR), Raman, and X-ray absorption spectroscopy (XAS). The results indicate that the polyoxometalate structure is retained after grafting on silica and allows the stabilization of Ru(0) nanoparticles after reduction. The resulting system exhibits interesting catalytic activity in benzene hydrogenation.

Cellular Association and Assembly of a Multistage Delivery System

“…Favorably charged SPIONs (amine‐ or carboxy‐modified, respectively; Fe 3 O 4 /Fe 2 O 3 ; 10–15 or 30 nm; purchased from Ocean NanoTech, LLC, Springdale, AR) were added to the dry S1MPs at concentrations ranging from 0.1 to 5 mg mL −1 in a total volume of 10–25 µL. Borate buffer was used for loading by the incipient wetness method34–36 (0.01 M , pH 5.0 for amine‐modified SPIONs, and 50 m M , pH 8.5 for carboxylic acid‐modified SPIONs). For loading, particles were briefly sonicated, then incubated at room temperature with agitation (1300 rpm) for 10 min followed by no motion for 20 min.…”

Chirality in Polyoxometalate Chemistry

“…In catalysis, they are used as redox catalysts9–13 and Brønsted or Lewis acids 14–17. They are also suitable as supports for organometallic catalysts18,19 or nanoparticles 20,21. Because multielectron reduction without loss of the architecture is often reversible, they can be used as electron reservoirs 22.…”

Cellular Association and Assembly of a Multistage Delivery System

“…Springdale, AR) were added to the dry S1MPs at concentrations of ranging from 0.1-5 mg/ml in a total volume of 10-25 μl. Borate buffer was used for loading by the incipient wetness method [34][35][36] (0.01 M, pH 5.0 for amine modified SPIONs, and 50 mM, pH 8.5 for carboxylic acid modified SPIONs). For loading, particles were briefly sonicated, then incubated at room temperature with agitation (1300 rpm) for 10 min followed by no motion for 20 min.…”