Mild and Efficient Heterogeneous Hydrogenation of Nitroarenes Facilitated by a Pyrolytically Activated Dinuclear Ni(II)-Ce(III) Diimine Complex.

We communicate the assembly of a solid, Ce-promoted Ni-based composite that was applied as catalyst for the hydrogenation of nitroarenes to afford the corresponding organic amines. The catalytically active material described herein was obtained through pyrolysis of a SiO-pellet-supported bimetallic Ni-Ce complex that was readily synthesized prior to use from a MeO-functionalized salen congener, Ni(OAc)·4 HO, and Ce(NO)·6 HO. Rewardingly, the requisite ligand for the pertinent solution phase precursor was accessible upon straightforward and time-saving imine condensation of -vanillin with 1,3-diamino-2,2'-dimethylpropane.

Selective and Additive-Free Hydrogenation of Nitroarenes Mediated by a DMSO-Tagged Molecular Cobalt Corrole Catalyst.

We report on the first cobalt corrole that effectively mediates the homogeneous hydrogenation of structurally diverse nitroarenes to afford the corresponding amines. The given catalyst is easily assembled prior to use from 4--butylbenzaldehyde and pyrrole followed by metalation of the resulting corrole macrocycle with cobalt(II) acetate. The thus-prepared complex is self-contained in that the hydrogenation protocol is free from the requirement for adding any auxiliary reagent to elicit the catalytic activity of the applied metal complex.

Liquid-Phase Hydrogenation of Nitriles to Amines Facilitated by a Co(II)/Zn(0) Pair: A Ligand-Free Catalytic Protocol.

The given report introduces a simple and user-friendly in situ method for the production of catalytically active cobalt particles. The approach circumvents the use of air- and moisture-sensitive reductants as well as the application of anhydrous Co-precursor salts. Accordingly, the described catalytic system is readily assembled under open-flask conditions by simply combining the components in the reaction vessel.

Biomass-Derived Catalysts for Selective Hydrogenation of Nitroarenes.

Development of catalytically active materials from biowaste represents an important aspect of sustainable chemical research. Three heterogeneous materials were synthesized from inexpensive biomass-based chitosan and abundant Co(OAc) using complexation followed by pyrolysis at various temperatures. These materials were applied in the catalytic hydrogenation of nitroarenes using molecular hydrogen.

Stable and Inert Cobalt Catalysts for Highly Selective and Practical Hydrogenation of C≡N and C═O Bonds.

Novel heterogeneous cobalt-based catalysts have been prepared by pyrolysis of cobalt complexes with nitrogen ligands on different inorganic supports. The activity and selectivity of the resulting materials in the hydrogenation of nitriles and carbonyl compounds is strongly influenced by the modification of the support and the nitrogen-containing ligand. The optimal catalyst system ([Co(OAc)2/Phen@α-Al2O3]-800 = Cat.

Selective Catalytic Hydrogenations of Nitriles, Ketones, and Aldehydes by Well-Defined Manganese Pincer Complexes.

Hydrogenations constitute fundamental processes in organic chemistry and allow for atom-efficient and clean functional group transformations. In fact, the selective reduction of nitriles, ketones, and aldehydes with molecular hydrogen permits access to a green synthesis of valuable amines and alcohols. Despite more than a century of developments in homogeneous and heterogeneous catalysis, efforts toward the creation of new useful and broadly applicable catalyst systems are ongoing.

Highly selective hydrogenation of arenes using nanostructured ruthenium catalysts modified with a carbon-nitrogen matrix.

Selective hydrogenations of (hetero)arenes represent essential processes in the chemical industry, especially for the production of polymer intermediates and a multitude of fine chemicals. Herein, we describe a new type of well-dispersed Ru nanoparticles supported on a nitrogen-doped carbon material obtained from ruthenium chloride and dicyanamide in a facile and scalable method. These novel catalysts are stable and display both excellent activity and selectivity in the hydrogenation of aromatic ethers, phenols as well as other functionalized substrates to the corresponding alicyclic reaction products.

Selective Catalytic Hydrogenation of Heteroarenes with N-Graphene-Modified Cobalt Nanoparticles (Co3O4-Co/NGr@α-Al2O3).

Cobalt oxide/cobalt-based nanoparticles featuring a core-shell structure and nitrogen-doped graphene layers on alumina are obtained by pyrolysis of Co(OAc)2/phenanthroline. The resulting core-shell material (Co3O4-Co/NGr@α-Al2O3) was successfully applied in the catalytic hydrogenation of a variety of N-heteroarenes including quinolines, acridines, benzo[h], and 1,5-naphthyridine as well as unprotected indoles. The peculiar structure of the novel heterogeneous catalyst enables activation of molecular hydrogen at comparably low temperature.

Synthesis and Characterization of Iron-Nitrogen-Doped Graphene/Core-Shell Catalysts: Efficient Oxidative Dehydrogenation of N-Heterocycles.

An important goal for nanocatalysis is the development of flexible and efficient methods for preparing active and stable core-shell catalysts. In this respect, we present the synthesis and characterization of iron oxides surrounded by nitrogen-doped-graphene shells immobilized on carbon support (labeled FeOx@NGr-C). Active catalytic materials are obtained in a simple, scalable and two-step method via pyrolysis of iron acetate and phenanthroline and subsequent selective leaching.

Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols.

The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids.

Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters.

Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides.

Design, synthesis and characterization of a modular bridging ligand platform for bio-inspired hydrogen production.

Synthesis and characterization of a novel type of ambident bridging ligands joining together the functional prerequisites for visible-light absorption, photoinduced electron transfer and catalytic proton reduction is presented. This class of compounds consists of a chromophoric 1,2-diimine-based π-acceptor site and a rigid polyaromatic dithiolate chelator. Due to the presence of a common conjugated linker moiety with an intrinsic two-electron redox reactivity and a suitable orbital coupling of the subunits, a favourable situation for vectorial multielectron transfer from attached electron donors to a catalytic acceptor site is provided.

μ(3)-Chlorido-tris-(bis-{1-[2-(dimethyl-amino)-eth-yl]-3-methyl-imidazol-2-yl-idene}silver(I)) dichloride.

In the crystal structure of the title compound, [Ag(3)Cl(C(8)H(15)N(3))(6)]Cl(2), the Ag(I) ion, which is located on a twofold rotation axis, exists in a T-shape coordination environment. Two carbene C atoms of the N-heterocyclic carbene (NHC) ligands are bonded tightly forming a slightly bent [Ag(NHC)(2)](+) cation [C-Ag-C angle = 162.80 (18)°].