Ionic Liquids in Metal, Photo-, Electro-, and (Bio) Catalysis

Ionic liquids (ILs) have unique physicochemical properties that make them advantageous for catalysis, such as low vapor pressure, non-flammability, high thermal and chemical stabilities, and the ability to enhance the activity and stability of (bio)catalysts. ILs can improve the efficiency, selectivity, and sustainability of bio(transformations) by acting as activators of enzymes, selectively dissolving substrates and products, and reducing toxicity. They can also be recycled and reused multiple times without losing their effectiveness. ILs based on imidazolium cation are preferred for structural organization aspects, with a semiorganized layer surrounding the catalyst. ILs act as a container, providing a confined space that allows modulation of electronic and geometric effects, miscibility of reactants and products, and residence time of species. ILs can stabilize ionic and radical species and control the catalytic activity of dynamic processes. Supported IL phase (SILP) derivatives and polymeric ILs (PILs) are good options for molecular engineering of greener catalytic processes. The major factors governing metal, photo-, electro-, and biocatalysts in ILs are discussed in detail based on the vast literature available over the past two and a half decades. Catalytic reactions, ranging from hydrogenation and cross-coupling to oxidations, promoted by homogeneous and heterogeneous catalysts in both single and multiphase conditions, are extensively reviewed and discussed considering the knowledge accumulated until now.

Tailoring graphene-supported Ru nanoparticles by functionalization with pyrene-tagged N-heterocyclic carbenes

Controlling the reactivity and stability of graphene-supported Ru NPs by modifying their surface with pyrene-tagged N-heterocyclic carbene ligands.

Controlling the selectivity of bimetallic platinum–ruthenium nanoparticles supported on N-doped graphene by adjusting their metal composition

Bimetallic platinum–ruthenium nanoparticles supported on N-doped graphene as chemoselective hydrogenation catalysts.

Rh nanoparticles from thiolate dimers: selective and reusable hydrogenation catalysts in ionic liquids

Thiolate-capped RhNPs in imidazolium-based ionic liquids were synthesized from [Rh(μ-SR)(COD)]₂ dimmers under H₂ pressure without external addition of ligand stabilizers, preserving thiolate integrity on the nanoparticle surface. This nanoparticulated systems showed a remarkable selectivity that led to their application in the one pot reductive N-alkylation to produce amines.

Highly efficient aqueous phase reduction of nitroarenes catalyzed by phosphine-decorated polymer immobilized ionic liquid stabilized PdNPs

Phosphino-decorated polymer immobilised ionic liquid-stabilised PdNPs are highly efficient catalysts for the aqueous phase hydrogenation and transfer hydrogenation of aromatic nitro compounds in batch and continuous flow.

Tuning the chemoselective hydrogenation of aromatic ketones, aromatic aldehydes and quinolines catalyzed by phosphine functionalized ionic liquid stabilized ruthenium nanoparticles

Aromatic ketones, aromatic aldehydes and quinolines can be hydrogenated with switchable excellent chemoselectivity under mild conditions catalyzed by ruthenium nanoparticles.

Palladium metal nanoparticles stabilized by ionophilic ligands in ionic liquids: synthesis and application in hydrogenation reactions

The selectivity of the hydrogenation of 1,3-cyclohexadiene and 2-pentyne by Pd nanoparticles in an ionic liquid can be modulated by the addition of N- or P-containing ionophilic ligands.

Ag–Pd and CuO–Pd nanoparticles in a hydroxyl-group functionalized ionic liquid: synthesis, characterization and catalytic performance

Heteronuclear Ag–Pd and CuO–Pd nanoparticles with a controllable Ag : Pd or Cu : Pd ratio were easily synthesized through thermal decomposition of their acetate salts in a functionalized ionic liquid, [C₂OHmim][NTf₂].

Preparation of catalytic materials using ionic liquids as the media and functional components

Ionic liquids (ILs) have attracted much attention due to their unique properties and wide application potential in a variety of fields. The unusual properties of ILs provide numerous opportunities to design and prepare arious advanced materials, including highly efficient catalysts. In recent years, synthesis of different kinds of catalytic materials and their applications in chemical reactions have been studied extensively and have become a very interesting area. Herein, we present a review on the synthesis of catalytic materials using ILs as the media and/or functional components; the important and widely investigated topics are discussed, including mainly metal nanocatalysts/IL, functional IL/support, metals or metal oxides/IL/support, polymeric ILs (PILs) catalysts, and the performances of catalytic systems are highlighted. An outlook for this interesting area is also given at the end of the article.

Nanocatalysis: Academic Discipline and Industrial Realities

Nanotechnology plays a central role in both academic research and industrial applications. Nanoenabled products are not only found in consumer markets, but also importantly in business to business markets (B2B). One of the oldest application areas of nanotechnology is nanocatalysis—an excellent example for such a B2B market. Several existing reviews illustrate the scientific developments in the field of nanocatalysis. The goal of the present review is to provide an up-to-date picture of academic research and to extend this picture by an industrial and economic perspective. We therefore conducted an extensive search on several scientific databases and we further analyzed more than 1,500 nanocatalysis-related patents and numerous market studies. We found that scientists today are able to prepare nanocatalysts with superior characteristics regarding activity, selectivity, durability, and recoverability, which will contribute to solve current environmental, social, and industrial problems. In industry, the potential of nanocatalysis is recognized, clearly reflected by the increasing number of nanocatalysis-related patents and products on the market. The current nanocatalysis research in academic and industrial laboratories will therefore enable a wealth of future applications in the industry.

Nanometallic chemistry: deciphering nanoparticle catalysis from the perspective of organometallic chemistry and homogeneous catalysis

Nanoparticle (NP) catalysis is traditionally viewed as a sub-section of heterogeneous catalysis. However, certain properties of NP catalysts, especially NPs dispersed in solvents, indicate that there could be benefits from viewing them from the perspective of homogeneous catalysis. By applying the fundamental approaches and concepts routinely used in homogeneous catalysis to NP catalysts it should be possible to rationally design new nanocatalysts with superior properties to those currently in use.