Arene Hydrogen Research Articles

Palladated halloysite hybridized with photo‐polymerized hydrogel in the presence of cyclodextrin: An efficient catalytic system benefiting from nanoreactor concept

Considering the excellent performance of halloysite as a catalyst support and in an attempt to benefit from the concept of nanoreactors in the catalysis, an innovative catalytic system has been designed, in which acrylamide and bis‐acrylamide were photo‐polymerized in the presence of palladated halloysite. The novel precipitation photo‐polymerization method avoided the formation of an extended polymeric network, but led to the formation of co‐polymer on the halloysite periphery. The co‐polymer exhibited good swellability in aqueous media and formed hydrogel. This hydrophilic environment around catalytic palladated halloysite can be considered as a nanoreactor that can concentrate the substrate and bring them into the vicinity of the palladated halloysite. This catalytic system was used for promoting hydrogenation of hydrophobic nitro arenes in aqueous media. To avoid immiscibility of hydrophobic substrates and hydrophilic nature of the nanoreactor, that emerged from swelling of hydrogel, β‐cyclodextrin (CD) was utilized as phase transfer agent. The results confirmed high catalytic activity of this catalytic system. Even highly hydrophobic substrates could tolerate hydrogenation under this protocol to furnish the corresponding product in high yield. Finally, the contribution of both CD and hydrogel to the catalysis was confirmed. Moreover, studying the recyclability of the catalyst as well as Pd leaching proved the high recyclability of the catalyst and low leaching of Pd nanoparticles.

Three closely related 1-[(1,3-benzodioxol-5-yl)methyl]-4-(halobenzo-yl)piperazines: similar mol-ecular structures but different inter-molecular inter-actions.

In each of the compounds 1-[(1,3-benzodioxol-5-yl)methyl]-4-(3-fluoro-benzo-yl)piperazine, C19H19FN2O3 (I), 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,6-di-fluoro-benzo-yl)piperazine, C19H18F2N2O3 (II), and 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,4-di-chloro-benzo-yl)piperazine, C19H19Cl2N2O3 (III), the piperazine rings adopt a chair conformation with the (1,3-benzodioxol-5-yl)methyl substituent occupying an equatorial site: the five-membered rings are all slightly folded across the O⋯O line leading to envelope conformations. The dihedral angle between the planar amidic fragment and the haloaryl ring is 62.97 (5)° in (I) but 77.72 (12)° and 75.50 (5)° in (II) and (III), respectively. Despite their similarity in constitution and conformation, the supra-molecular inter-actions in (I)-(III) differ: in (I), a combination of C-H⋯O and C-H⋯π(arene) hydrogen bonds links the mol-ecules into a three-dimensional framework structure, but there are no hydrogen bonds of any sort in either (II) or (III), although the structure of (III) contains a short Cl⋯Cl contact between inversion-related pairs of mol-ecules.

The crystal structure of 1-(2-iodo-benzo-yl)-4-(pyrimidin-2-yl)piperazine: a three-dimensional hydrogen-bonded framework, augmented by π-π stacking inter-actions and I⋯N halogen bonds.

In 1-(2-iodo-benzo-yl)-4-(pyrimidin-2-yl)piperazine, C15H15IN4O, the central piperazine ring adopts an almost perfect chair conformation with the pyrimidine substituent in an equatorial site. The planar amide unit makes a dihedral angle of 80.44 (7)° with the phenyl ring. A combination of C-H⋯O and C-H⋯π(arene) hydrogen bonds links the mol-ecules into a complex three-dimensional network structure, augmented by a π-π stacking inter-action and an I⋯N halogen bond, all involving different pairs of inversion-related mol-ecules. Comparisons are made with the structures of a number of related compounds.

A Catalytic Hydrogenation of Arenes: Batch versus Flow

Key words bimetallic catalyst - nanoparticles - rhodium catalysis - platinum catalysis - arenes - hydrogenation

Arene Hydrogenation by Metal Nanoparticles in Ionic Liquids

AbstractIonic liquids (ILs) have been extensively explored in controlling the selectivity and stability of metal nanoparticles and/or classical heterogeneous catalysts for the hydrogenation of aromatics. ILs provide a protective layer to metal surface catalysts and a physical barrier controlling the access of substrates/intermediates/products on the nanoconfined catalysts, acting as an electronic and geometrical modifier of the catalytic active sites. As a result, this allows the stability and electronic/geometrical properties of the catalyst to be modulated. The IL layers also allow nano‐environments to be designed for encapsulation and to change the kinetic/thermodynamic of the process compared to those reactions performed in classical heterogeneous catalysis. We will focus on the physical, geometric and electronic effects imposed by the IL on metal nanoparticles and classical heterogeneous catalysts on activity and selectivity in the hydrogenation of arenes, in particular benzene.

Four 1-aryl-1H-pyrazole-3,4-di-carboxyl-ate derivatives: synthesis, mol-ecular conformation and hydrogen bonding.

Four 1-aryl-1H-pyrazole-3,4-di-carboxyl-ate derivatives, one acid, two esters and a dicarbohydrazide have been synthesized starting from 3-aryl sydnones, and structurally characterized. There is an intra-molecular O-H⋯O hydrogen bond in 1-phenyl-1H-pyrazole-3,4-di-carb-oxy-lic acid, C11H8N2O4, (I), and the mol-ecules are linked into a three-dimensional framework structure by a combination of O-H⋯O, O-H⋯N, C-H⋯O and C-H⋯π(arene) hydrogen bonds. In each of the two esters dimethyl 1-phenyl-1H-pyrazole-3,4-di-carboxyl-ate, C13H12N2O4, (II), and dimethyl 1-(4-methyl-phen-yl)-1H-pyrazole-3,4-di-carboxyl-ate, C14H14N2O4, (III), C-H⋯O hydrogen bonds lead to the formation of cyclic centrosymmetric dimers: in (III), one of the meth-oxy-carbonyl groups is disordered over two sets of atomic sites having occupancies 0.71 (2) and 0.29 (2). An intra-molecular N-H⋯O hydrogen bond is present in the structure of 1-(4-meth-oxy-phen-yl)-1H-pyrazole-3,4-dicarbohydrazide, C12H14N6O3, (IV), and the mol-ecules are linked into a three-dimensional framework structure by a combination of N-H⋯O, N-H⋯N, N-H⋯π(arene) and C-H⋯O hydrogen bonds. Comparisons are made with the structures of a number of related compounds.

Composite of ionic liquid decorated cyclodextrin nanosponge, graphene oxide and chitosan: A novel catalyst support

A biocompatible hybrid system composed of graphene oxide (GO), chitosan (CS) and ionic liquid decorated cyclodextrin nanosponge (CDNS-IL) is synthesized and applied for the immobilization of Pd and Fe3O4 nanoparticles to furnish a magnetic catalyst, Fe3O4/Pd@Hybrid. The justification for designing this hybrid system was benefiting from the capability of CDNS for formation of inclusion complex with substrates and acting as phase transfer agent. Moreover, IL itself could exert catalytic activity and improve anchoring Pd, while magnetic nanoparticles could render the catalyst easily separable. Moreover, the functional groups on CS could contribute to Pd anchoring. The catalytic activity of Fe3O4/Pd@Hybrid for promoting hydrogenation of nitro arenes and two coupling reactions in aqueous media was investigated. The results established that the catalyst could efficiently promote all the reactions under mild reaction condition. The investigation of the catalyst recyclability confirmed that the catalyst could be recycled for three reaction runs.

Poly(tetrafluoroethylene)-Stabilized Metal Nanoparticles: Preparation and Evaluation of Catalytic Activity for Suzuki, Heck, and Arene Hydrogenation in Water.

Poly(tetrafluoroethylene)-stabilized Pd nanoparticles (PTFE-PdNPs) were prepared in water with 4-methylphenylboronic acid as a reductant and characterized using powder X-ray diffraction, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Small PdNPs with a fairly uniform size were obtained in the presence of PTFE, whereas aggregation of palladium was observed in the absence of PTFE. PTFE-PdNPs showed high catalytic activity for the Suzuki coupling reaction in water and were reused without any loss of activity. No palladium species were observed by ICP-AES analysis in the reaction solution after the reaction, nor was any change in particle size observed after the recycle experiment. PTFE-PdNPs also exhibited excellent catalytic activity and reusability for the Heck reaction in water. Although palladium species were not detected in the reaction solution after the reaction, aggregates and smaller sizes of PdNPs were observed in the TEM image of the recovered catalyst. PTFE was also useful as the stabilizer of rhodium nanoparticles (RhNPs) prepared by reduction with NaBH4. PTFE-RhNPs showed high catalytic activity and reusability toward arene hydrogenation under mild conditions.

Polysilane-Immobilized Rh-Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism.

Hydrogenation of arenes is an important reaction not only for hydrogen storage and transport but also for the synthesis of functional molecules such as pharmaceuticals and biologically active compounds. Here, we describe the development of heterogeneous Rh-Pt bimetallic nanoparticle catalysts for the hydrogenation of arenes with inexpensive polysilane as support. The catalysts could be used in both batch and continuous-flow systems with high performance under mild conditions and showed wide substrate generality. In the continuous-flow system, the product could be obtained by simply passing the substrate and 1 atm H2 through a column packed with the catalyst. Remarkably, much higher catalytic performance was observed in the flow system than in the batch system, and extremely strong durability under continuous-flow conditions was demonstrated (>50 days continuous run; turnover number >3.4 × 105). Furthermore, details of the reaction mechanisms and the origin of different kinetics in batch and flow were studied, and the obtained knowledge was applied to develop completely selective arene hydrogenation of compounds containing two aromatic rings toward the synthesis of an active pharmaceutical ingredient.

Rh(CAAC)-Catalyzed Arene Hydrogenation: Evidence for Nanocatalysis and Sterically Controlled Site-Selective Hydrogenation

We report the arene hydrogenation of ethers, amides, and esters at room temperature and low hydrogen pressure, starting from [(CAAC)Rh(COD)Cl] (CAAC = cyclic alkyl amino carbene). Kinetic, mechanis...

Silylarene Hydrogenation: A Strategic Approach that Enables Direct Access to Versatile Silylated Saturated Carbo- and Heterocycles.

We report a method to convert readily available silylated arenes into silylated saturated carbo- and heterocycles by arene hydrogenation. The scope includes alkoxy- and halosilyl substituents. Silyl groups can be derivatized into a plethora of functionalities and find application in organic synthesis, materials science, and pharmaceutical, agrochemical, and fragrance research. However, silylated saturated (hetero- ) cycles are difficult to access with current technologies. The yield of the hydrogenation depends on the amount of the silica gel additive. This silica effect also enables a significant improvement of a previously disclosed method for the hydrogenation of highly fluorinated arenes (e.g., to all-cis-C6 H6 F6 ).

Pyridine(diimine) Molybdenum-Catalyzed Hydrogenation of Arenes and Hindered Olefins: Insights into Precatalyst Activation and Deactivation Pathways

Pyridine(diimine) molybdenum bis(olefin) and bis(alkyl) complexes were synthesized, characterized, and examined for their catalytic activity in the hydrogenation of benzene and a selection of substituted arenes. The molybdenum bis(alkyl) complex (4-tBu-iPrPDI)Mo(CH2SiMe3)2 (iPrPDI = 2,6-(2,6-(C(CH3)2H)2C6H3N═CMe)2C5H3N) exhibited the highest activity for the hydrogenation of benzene, producing cyclohexane in >98% yield at 23 °C under 4 atm of hydrogen after 48 h. Toluene and o-xylene were similarly hydrogenated to their respective cycloalkanes, with the latter yielding predominantly (79:21 dr) cis-1,2-dimethylcyclohexane. The molybdenum-catalyzed hydrogenation of naphthalene yielded tetralin exclusively, and this selectivity was maintained at higher H2 pressure. At 32 atm of H2, more hindered arenes such as monosubstituted benzenes, biphenyl, and m- and p-xylenes underwent hydrogenation with yields ranging between 20 and >98%. (4-tBu-iPrPDI)Mo(CH2SiMe3)2 was also a competent alkene hydrogenation catalyst,...

Reinvestigation of the crystal structure of N-(4-chloro-benzyl-idene)-2-hy-droxy-aniline: a three-dimensional structure containing O-H⋯N, O-H⋯O and C-H⋯π(arene) hydrogen bonds.

The mol-ecule of the title compound, C13H10ClNO, (I), which contains an intra-molecular O-H⋯N hydrogen bond, is almost planar: the dihedral angle between the two aryl rings is only 3.31 (9)°. The mol-ecules of (I) are linked into sheets by two C-H⋯π(arene) hydrogen bonds and the sheets are linked into a three-dimensional structure by O-H⋯O hydrogen bonds. Comparisons are made with the structures of a number of related compounds.

A concise, efficient and versatile synthesis of amino-substituted benzo[b]pyrimido[5,4-f]azepines: synthesis and spectroscopic characterization, together with the molecular and supramolecular structures of three products and one intermediate.

A concise, efficient and versatile synthesis of amino-substituted benzo[b]pyrimido[5,4-f]azepines is described: starting from a 5-allyl-4,6-dichloropyrimidine, the synthesis involves base-catalysed aminolysis followed by intramolecular Friedel-Crafts cyclization. Four new amino-substituted benzo[b]pyrimido[5,4-f]azepines are reported, and all the products and reaction intermediates have been fully characterized by IR, 1H and 13C NMR spectroscopy and mass spectrometry, and the molecular and supramolecular structures of three products and one intermediate have been determined. In each of N,2,6,11-tetramethyl-N-phenyl-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepin-4-amine, C22H24N5, (III), 4-(1H-benzo[d]imidazol-1-yl)-6,11-dimethyl-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepine, which crystallizes as a 0.374-hydrate, C21H19N5·0.374H2O, (VIIIa), and 6,7,9,11-tetramethyl-4-(5-methyl-1H-benzo[d]imidazol-1-yl)-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepine, C24H25N5, (VIIIc), the azepine ring adopts a boat conformation, but with a different configuration at the stereogenic centre in (VIIIc), as compared with (III) and (VIIIa). In the intermediate 5-allyl-6-(1H-benzo[d]imidazol-1-yl)-N-methyl-N-(4-methylphenyl)pyrimidin-4-amine, C22N21N5, (VIIb), the immediate precursor of 4-(1H-benzo[d]imidazol-1-yl)-6,8,11-trimethyl-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepine, (VIIIb), the allyl group is disordered over two sets of atomic sites having occupancies of 0.688 (5) and 0.312 (5). The molecules of (III) are linked into chains by a C-H...π(pyrimidine) hydrogen bond, and those of (VIIb) are linked into complex sheets by three hydrogen bonds, one of the C-H...N type and two of C-H...π(arene) type. The molecules of the organic component in (VIIIa) are linked into a chain of rings by two C-H...π(arene) hydrogen bonds, and these chains are linked into sheets by the water components; a single weak C-H...N hydrogen bond links molecules of (VIIIc) into centrosymmetric R22(10) dimers. Comparisons are made with some related compounds.

Preparation, characterization, and hydrogenation activity of new Rh0–MCM-41 catalysts prepared from as-synthesized MCM-41 and RhCl3

Impregnation of as-synthesized MCM-41 silica by ethanolic solutions of rhodium(III) chloride was tested as an alternative to its introduction into the synthesis gel to get, after calcination and reduction by H 2 , highly dispersed metal(0) nanoparticles throughout the mesopores network. Rh(III) and Rh(0)–based solids thus obtained were analyzed by infrared spectroscopy, elemental analysis, transmission electron microscopy, N 2 sorption, and X-ray diffraction. Materials with 1.6 wt % of rhodium could be obtained as a result of CTA + /Rh 3+ exchange. The determining role of CTA + was emphasized through blank experiments. In a second series of materials, ethanol was also exploited for its ability to reduce Rh(III). All Rh(0)-based solids were tested as catalysts in the hydrogenation of styrene under mild temperature and pressure conditions. Catalysis performances of the most efficient sample (reduced by H 2 ) were further compared with those of a very similar material prepared by the introduction of Rh(III) directly into the synthesis gel of MCM-41 silica. Better cis selectivities in the hydrogenation of disubstituted arene derivatives were achieved with materials issued from the new preparation method. Ammonium template facilitates incorporation of Rh(III) in the as-synthesized MCM-41 in ethanol, thus affording, after an ex situ reduction step, catalytically active dispersions of Rh(0) with a high cis selectivity in the hydrogenation of disubstituted arenes. • The role of cetyltrimethylammonium in the uptake process of rhodium(III) was clearly demonstrated in ethanol. • Relationship between surfactant removal and rhodium incorporated was tested at different nominal molar Si/Rh ratios. • Ethanol can also be used as a reducing agent provided that the reaction is carried out ex-situ. • Differences were highlighted between the materials prepared according to this new path and that of direct hydrothermal synthesis. • Resulting materials lead to a better selectivity in cis hydrogenated compounds compared to samples prepared by DHT.

A Novel Tetramethylpyrazine Derivative Prophylactically Protects against Glutamate-Induced Excitotoxicity in Primary Neurons through the Blockage of N-Methyl-D-aspartate Receptor.

The over-activation of NMDA receptor via the excessive glutamate is believed to one of the most causal factors associated with Alzheimer’s disease (AD), a progressive neurodegenerative brain disorder. Molecules that could protect against glutamate-induced neurotoxicity may hold therapeutic values for treating AD. Herein, the neuroprotective mechanisms of dimeric DT-010, a novel derivative of naturally occurring danshensu and tetramethylpyrazine, were investigated using primary rat cerebellar granule neurons (CGNs) and hippocampal neurons. It was found that DT-010 (3–30 μM) markedly prevented excitotoxicity of CGNs caused by glutamate, as evidenced by the promotion of neuronal viability as well as the reversal of abnormal morphological changes. While its parent molecules did not show any protective effects even when their concentration reached 50 μM. Additionally, DT-010 almost fully blocked intracellular accumulation of reactive oxygen species caused by glutamate and exogenous oxidative stimulus. Moreover, Western blot results demonstrated that DT-010 remarkably attenuated the inhibition of pro-survival PI3K/Akt/GSK3β pathway caused by glutamate. Ca2+ imaging with Fluo-4 fluorescence analysis further revealed that DT-010 greatly declined glutamate-induced increase in intracellular Ca2+. Most importantly, with the use of whole-cell patch clamp electrophysiology, DT-010 directly inhibited NMDA-activated whole-cell currents in primary hippocampal neurons. Molecular docking simulation analysis further revealed a possible binding mode that inhibited NMDA receptor at the ion channel, showing that DT-010 favorably binds to Asn602 of NMDA receptor via arene hydrogen bond. These results suggest that DT-010 could be served as a novel NMDA receptor antagonist and protect against glutamate-induced excitotoxicity from blocking the upstream NMDA receptors to the subsequent Ca2+ influx and to the downstream GSK3β cascade.

Synthesis and structures of six closely related N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]arylamides, together with an isolated reaction intermediate: order versus disorder, molecular conformations and hydrogen bonding in zero, one and two dimensions.

Six closely related N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]arylamides have been synthesized and structurally characterized, together with a representative reaction intermediate. In each of N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]benzamide, C20H16ClNO2S, (I), N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-4-phenylbenzamide, C26H20ClNO2S, (II), and 2-bromo-N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]benzamide, C20H15BrClNO2S, (III), the molecules are disordered over two sets of atomic sites, with occupancies of 0.894 (8) and 0.106 (8) in (I), 0.832 (5) and 0.168 (5) in (II), and 0.7006 (12) and 0.2994 (12) in (III). In each of N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-2-iodobenzamide, C20H15ClINO2S, (IV), and N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-2-methoxybenzamide, C21H18ClNO3S, (V), the molecules are fully ordered, but in N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-2,6-difluorobenzamide, C20H14ClF2NO2S, (VI), which crystallizes with Z' = 2 in the space group C2/c, one of the two independent molecules is fully ordered, while the other is disordered over two sets of atomic sites having occupancies of 0.916 (3) and 0.084 (3). All of the molecules in compounds (I)-(VI) exhibit an intramolecular N-H...O hydrogen bond. The molecules of (I) and (VI) are linked by C-H...O hydrogen bonds to form finite zero-dimensional dimers, which are cyclic in (I) and acyclic in (VI), those of (III) are linked by C-H...π(arene) hydrogen bonds to form simple chains, and those of (IV) and (V) are linked into different types of chains of rings, built in each case from a combination of C-H...O and C-H...π(arene) hydrogen bonds. Two C-H...O hydrogen bonds link the molecules of (II) into sheets containing three types of ring. In benzotriazol-1-yl 3,4-dimethoxybenzoate, C15H13N3O4, (VII), the benzoate component is planar and makes a dihedral angle of 84.51 (6)° with the benzotriazole unit. Comparisons are made with related compounds.

A Four-Step Synthesis of (±)-γ-Lycorane via Pd0-Catalyzed Double C(sp2)-H/C(sp3)-H Arylation.

An expedient synthesis of lycorine alkaloids is reported using a palladium(0)-catalyzed double C-X/C-H arylation as the key step. The selectivity of this reaction was controlled through the judicious choice of the two halogen atoms, and its generality was demonstrated through the construction of various substituted pyrrolophenanthridinones. A selective arene hydrogenation allowed for the completion of the synthesis of (±)-γ-lycorane in just four steps from commercially available precursors.

A versatile synthesis of cyclic dipeptides using the stepwise construction of the piperazine-2,5-dione ring from simple precursors: synthetic sequence and the structure of a representative product, (3RS)-4-(2-allyl-3,5-dimethylphenyl)-1-benzyl-3-phenylpiperazine-2,5-dione.

A versatile synthesis of multiply substituted cyclic dipeptides has been designed, based on the stepwise construction of the piperazine-2,5-dione ring using molecular fragments from four different precursor molecules. Starting from substituted 2-allylanilines, reaction with methyl 2-bromo-2-phenylacetate yields the corresponding methyl 2-(2-allylanilino)-2-phenylacetates, which react with haloacetyl chlorides to give methyl 2-[N-(2-allylphenyl)-2-haloacetamido]-2-phenylacetates, which then undergo ring closure with benzylamine to yield the corresponding cyclic dipeptides of type 4-(2-allylphenyl)-1-benzyl-3-phenylpiperazine-2,5-dione. (3RS)-4-(2-Allyl-3,5-dimethylphenyl)-1-benzyl-3-phenylpiperazine-2,5-dione, C28H28N2O2, (IIId), crystallizes with Z' = 2 in the space group P21/c; the allyl groups in the two independent molecules adopt different conformations and, in one of them, the allyl group is disordered over two sets of atomic sites having occupancies of 0.534 (4) and 0.466 (4). In both molecules, the piperazine-2,5-dione ring adopts a boat conformation, with the 3-phenyl ring in a quasi-axial site. The molecules of (IIId) are linked into a three-dimensional framework structure by a combination of three C-H...O hydrogen bonds and three C-H...π(arene) hydrogen bonds. Comparisons are made with some related structures.

Organometallic Ruthenium Nanoparticles: Synthesis, Surface Chemistry, and Insights into Ligand Coordination.

Although there has been for the past 20 years great interest in the synthesis and use of metal nanoparticles, little attention has been paid to the complexity of the surface of these species. In particular, the different aspects concerning the ligands present, their location, their mode of binding, and their dynamics have been little studied. Our group has started in the early 1990s an investigation of the surface coordination chemistry of ruthenium and platinum nanoparticles but at that time with a lack of adequate techniques to fulfill our ambition. Over 10 years later, we went back to this problem and could obtain a more precise vision of the surface species. This Account is centered on ruthenium chemistry. This metal has been the most studied in our group, first thanks to the availability of a precursor, Ru(cyclooctadiene)(cyclooctatriene) (Ru(COD)(COT)), which possesses the ability to decompose in very mild conditions without leaving residues on the resulting nanoparticles and second because of the absence of magnetic perturbations (Knight shift, paramagnetism, ferromagnetism, etc.), which has allowed the use of solution and solid state NMR. In this respect, it has been possible to evidence the presence of a high concentration of hydrides on the surface of these particles, to study their dynamics, and to show that since the polarity of the Ru-H bond is similar to that of the C-H bond, a Ru/H NP would behave as a big lipophilic entity. The second point was to characterize the coordination of ancillary ligands. This has been achieved for different ligands, in particular phosphines and carbenes, which made possible the study of the modification of NP reactivity induced by surface ligands. This led to the conclusion that the presence of surface ligands can benefit both the activity of NP catalysts and their selectivity. If it was expected that the selectivity could be modulated, the promoting effect from the presence of ligands on, for example, arene or CO hydrogenation was totally unexpected. Playing with poison atoms (Sn, Fe, etc.) or ligands (CO) may allow us to play with the reactivity of the NPs to make them more selective for selected reactions. Finally, the search for specific ligands for nanoparticles is still in its infancy, but some examples have been found as have specific reactions of nanoparticles. Obviously arene hydrogenation and CO hydrogenation were well-known in heterogeneous catalysis, but we could demonstrate that they can be carried out in very mild conditions on ligand stabilized RuNPs. On the other hand, the enantiospecific C-H activation leading to enantioselective labeling of large organic or biomolecules or the C-C bond cleavage in mild conditions were both unexpected. There is still much work to perform for reaching the degree of control on nanoparticles that is presently achieved in organometallic molecular chemistry, but this work shows that it is possible.