Ruthenium Nanoparticles in Ionic Liquids – A Saga

Campbell, Paul S.; Prechtl, Martin H. G.; Santini, Catherine C.; Haumesser, Paul‐Henri

doi:10.2174/1385272811317040008

Cited by 38 publications

(23 citation statements)

References 95 publications

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“…More stable nanoparticle-based catalytic systems can be obtained in ILs by the addition of ligands or polymeric stabilizers. Transitionmetal nanoparticles dispersed in ILs have been described as active catalysts for various reactions such as the hydrogenation of alkenes, arenes and ketones [60]. Further examples are given in dedicated reviews by Gu [78] and Dupont [57].…”

Section: Liquid-ionic Liquid Biphasic Transition Metal Catalysismentioning

confidence: 99%

Ionic Liquids in Catalysis

2014

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Ionic liquids (ILs), salts with melting points below 100°C, represent a fascinating class of liquid materials typically characterized by an extremely low vapor pressure. Besides their application as new solvents or as electrolytes for electrochemical purposes, there are two important concepts of using ILs in catalysis: Liquid-liquid biphasic catalysis and IL thin film catalysis. Liquid-liquid biphasic catalysis enables either a very efficient manner to apply catalytic ILs, e.g. in Friedel-Crafts reactions, or to apply ionic transition metal catalyst solutions. In both cases, phase separation after reaction allows an easy separation of reaction products and catalyst re-use. One problem of liquidliquid biphasic catalysis is mass transfer limitation. If the chemical reaction is much faster than the liquid-liquid mass transfer the latter limits the overall reaction rate. This problem is overcome in IL thin film catalysis where diffusion pathways and thus the characteristic time of diffusion are short. Here, Supported Ionic Liquid Phase (SILP) and Solid Catalyst with Ionic Liquid Layer (SCILL) are the two most important concepts. In both, a high surface area solid substrate is covered with a thin IL film, which contains either a homogeneously dissolved transition metal complex for SILP, or which modifies catalytically active surface sites at the support for SCILL. In each concept, interface phenomena play a very important role: These may concern the interface of an IL phase with an organic phase in the case of liquidliquid biphasic catalysis. For IL thin film catalysis, the interfaces of the IL with the gas phase and with catalytic nanoparticles and/or support materials are of critical importance. It has recently been demonstrated that these interfaces and also the bulk of ILs can be investigated in great detail using surface science studies, which greatly contributed to the fundamental understanding of the catalytic properties of ILs and supported IL materials. Exemplary results concerning the IL/vacuum or IL/gas interface, the solubility and surface enrichment of dissolved metal complexes, the IL/support interface and the in situ monitoring of chemical reactions in ILs are presented.

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Section: Liquid-ionic Liquid Biphasic Transition Metal Catalysismentioning

confidence: 99%

Ionic Liquids in Catalysis

2014

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“…Generally, the catalytic properties (activity and selectivity) of dispersed M-NPs indicate that they possess pronounced surface-like (multi-site) rather than singlesite-like character [222,223]. Fe- [13], Ru- [14], Rh- [15] and Ir-NPs [16] have been the subject of reviews concerning their synthesis, stabilization and size-control by various methods and also in different ILs, followed by a survey of their catalytic activity in organic hydrogenation [13,15,16], hydroformylation [15] and cross-coupling [13] reactions, in multiphase conditions [14,15] and in energy-related processes such as biomass refinement [14].…”

Section: Catalytic Applications Of Metal Nanoparticles Derived From Mmentioning

confidence: 99%

Ionic Liquids for the Synthesis and Stabilization of Metal Nanoparticles

Janiak

2013

Zeitschrift Für Naturforschung B

131

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The synthesis and stabilization of metal nanoparticles (M-NPs) from metals, metal salts, metal complexes and metal carbonyls in ionic liquids (ILs) is reviewed. The electrostatic and steric properties of ionic liquids allow for the stabilization of M-NPs without the need of additional stabilizers, surfactants or capping ligands. The synthesis of M-NPs in ILs can be carried out by chemical or electroreduction, thermolysis and photochemical methods including decomposition by microwave or sono-/ultrasound irradiation. Gas-phase syntheses can use sputtering, plasma/glow-discharge electrolysis and physical vapor deposition or electron beam and γ-irradiation. Metal carbonyl precursors M x (CO) y contain the metal atoms already in the zero-valent oxidation state needed for M-NPs so that no extra reducing agent is necessary. Microwave-induced thermal decomposition of precursors in ILs is a rapid and energy-saving access to M-NPs because of the significant absorption efficiency of ILs for microwave energy due to their ionic charge, high polarity and high dielectric constant. M-NP/IL dispersions can be applied in catalytic reactions, e. g., in C-C coupling or hydrogenation catalysis.

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“…4,8,9 As a result, the metal surface is accessible and active. This can be easily demonstrated by testing the catalytic properties of these NPs.…”

Section: Catalytic Activitymentioning

confidence: 99%

Ru-core/Cu-shell bimetallic nanoparticles with controlled size formed in one-pot synthesis

et al. 2014

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Suspensions of bimetallic nanoparticles (NPs) of Ru and Cu have been synthesized by simultaneous decomposition of two organometallic compounds in an ionic liquid. These suspensions have been characterized by Anomalous Small-Angle X-ray Scattering (ASAXS) at energies slightly below the Ru K-edge. It is found that the NPs adopt a Ru-core, a Cu-shell structure, with a constant Ru core diameter of 1.9 nm for all Ru : Cu compositions, while the Cu shell thickness increases with Cu content up to 0.9 nm. The formation of RuCuNPs thus proceeds through rapid decomposition of the Ru precursor into RuNPs of constant size followed by the reaction of the Cu precursor and agglomeration as a Cu shell. Thus, the different decomposition kinetics of precursors make possible the elaboration of core-shell NPs composed of two metals without chemical affinity.

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Ruthenium Nanoparticles in Ionic Liquids – A Saga

Cited by 38 publications

References 95 publications

Ionic Liquids in Catalysis

Ionic Liquids in Catalysis

Ionic Liquids for the Synthesis and Stabilization of Metal Nanoparticles

Ru-core/Cu-shell bimetallic nanoparticles with controlled size formed in one-pot synthesis

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