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International audience; The highly selective ruthenium-catalyzed ortho-C-H bond arylations have met a level of maturity that makes them an attractive tool to achieve unique organic transformations. By means of the manifold mechanisms operating in the presence of different arylating agents and reaction conditions, these methodologies have succeeded in reducing the wastes/steps toward the desired molecules as well as enlarging the chemical space by affording molecules impossible to obtain otherwise. The key achievements in this area are discussed in this article.

In recent years terpyridines (tpy) and mesoionic carbenes (MIC) have been widely used in metal complexes. With the right combination with a metal center, both of these ligands are individually known to generate excellent catalysts for CO2reduction. In this study, we combine the potentials of PFC (PFC=polyfluorocarbon) substituted tpy and MIC ligands within the same platform to obtain a new class of complexes, which we investigated with respect to their structural, electrochemical and UV/Vis/NIR spectroelectrochemical properties. We further show that the resulting metal complexes are potent electrocatalysts for CO2reduction in which CO is exclusively formed with a faradaic efficiency of 92 %. A preliminary mechanistic study, including the isolation and characterization of a key intermediate is also reported.

Rationally modulating the catalytic microenvironment is important for targeted induction of specific molecular behaviors to fulfill complicated catalytic purposes. Herein, a metal pre-chelating assisted assembly strategy is developed to facilely synthesize the hollow carbon spheres with ultrafine ruthenium clusters embedded in pore channels of the carbon shell (Ru@Shell-HCSs), which can be employed as nanoreactors with preferred electronic and geometric catalytic microenvironments for the efficient tandem hydrogenation of biomass-derived furfural toward 2-methylfuran. The channel-embedding structure is proved to confer the ultrafine ruthenium clusters with an electron-deficient property via a reinforced interfacial charge transfer mechanism, which prompts the hydrogenolysis of intermediate furfuryl alcohol during the tandem reaction, thus resulting in an enhanced 2-methylfuran generation. Meanwhile, lengthening the shell pore channel can offer reactant molecules with a prolonged diffusion path, and correspondingly a longer retention time in the channel, thereafter delivering an accelerated tandem hydrogenation progression. This paper aims to present a classic case that emphasizes the critical role of precisely controlling the catalytic microenvironment of the metal-loaded hollow nanoreactors in coping with the arduous challenges from multifunctional catalyst-driven complex tandem reactions.

International audience; The trans-mer-[(kappa(2)-N,S-NS2C7H4)PR3Ru{kappa(3)-H,S,S '-H2B (NS2C7H4)(2)}], (trans-mer-1 a: R=Cy; trans-mer-1 b: R=Ph) complexes are kinetically controlled products that upon thermolysis led to the formation of cis-mer-[(kappa(2)-N,S-NS2C7H4)PR3Ru{kappa(3)-H,S,S '-H2B(NS2C7H4)(2)}], (cis-mer-2 a: R=Cy; cis-mer-2 b: R=Ph) and cis-fac-[(kappa(2)-N,S-NS2C7H4)PR3Ru{kappa(3)-H,S,S '-H2B(NS2C7H4)(2)}], (cis-fac-3 a: R=Cy; cis-fac-3 b: R=Ph) along with complex cis-[(kappa(2)-N,S-NS2C7H4)(2)Ru(PPh3)(2)], (cis-4). One of the main intentions of this study was to examine the flexibility of the borate and hemilabile N,S-chelating mercapto-benzothiazole ligands in adapting different spatial arrangements around metal center. Multinuclear spectroscopic analyses have been done to characterize all new complexes and the structures were further confirmed by single-crystal X-ray diffraction analysis. Further, Density Functional Theory (DFT) calculations were performed to provide an insight into the bonding of the complexes.

We report the synthesis, photochemical and biological characterization of two new Ru(II) photoactivated complexes based on [Ru(tpy)(Me

A simple and efficient protocol allows the oxidation of the cyclopentadiene derivative 5H-dibenzo[e,h]-dibenzo[3,4 : 6,7]cyclohept[1,2-a]azulene (CpCH) provide according ketone CpCO. Comparable to the situation found for CpCH, the bending of the four annulated six-membered rings defines the C2 symmetric molecular structure of CpCO. The cyclopentadienone CpCO readily reacts with [Ru3(CO)12] and [Fe3(CO)12] to generate tricarbonyl complexes of the type [(η4-CpCO)M(CO)3]. In contrast to [(η4-CpCO)Ru(CO)3], the tricarbonyliron(0) complex is sensitive to oxygen and moisture. Refluxing [(η4-CpCO)Ru(CO)3] in isopropanol makes the hydrido-bridged complex [((η4-CpCO)2H)Ru2(CO)4H] accessible, an analogue to Shvo's catalyst. Both ruthenium complexes and their ligand CpCO were characterized spectroscopically and by single crystal x-ray diffraction. The activity of [(η4-CpCO)Ru(CO)3] was investigated for a series of transfer hydrogenation reactions.

We report new ruthenium complexes bearing the lipophilic bathophenanthroline (BPhen) ligand and dihydroxybipyridine (dhbp) ligands which differ in the placement of the OH groups ([(BPhen)(2)Ru(n,n′-dhbp)]Cl(2) with n = 6 and 4 in 1(A) and 2(A), respectively). Full characterization data are reported for 1(A) and 2(A) and single crystal X-ray diffraction for 1(A). Both 1(A) and 2(A) are diprotic acids. We have studied 1(A), 1(B), 2(A), and 2(B) (B = deprotonated forms) by UV-vis spectroscopy and 1 photodissociates but 2 is light stable. Luminescence studies reveal that the basic forms have lower energy (3)MLCT states relative to the acidic forms. Complexes 1(A) and 2(A) produce singlet oxygen with quantum yields of 0.05 and 0.68, respectively, in acetonitrile. Complexes 1 and 2 are both photocytotoxic towards breast cancer cells, with complex 2 showing EC(50) light values as low as 0.50 μM with PI values as high as >200 vs. MCF7. Computational studies were used to predict the energies of the (3)MLCT and (3)MC states. An inaccessible (3)MC state for 2(B) suggests a rationale for why photodissociation does not occur with the 4,4′-dhbp ligand. Low dark toxicity combined with an accessible (3)MLCT state for (1)O(2) generation explains the excellent photocytotoxicity of 2.

The use of iminophosphoryl-tethered ruthenium carbene complexes for activation of secondary phosphine P-H bonds is reported. Complexes of type [(p-cymene)-RuC(SO 2 Ph)(PPh 2 NR)] (with R = SiMe 3 or 4-C 6 H 4 -NO 2 ) were found to exhibit different reactivities depending on the electronics of the applied phosphine and the substituent at the iminophosphoryl moiety. Hence, the electron-rich silyl-substituted complex undergoes cyclometallation or shift of the imine moiety after cooperative activation of the P-H bond across the M=C linkage, depending on the electronics of the applied phosphine. Deuteration experiments and computational studies proved that cyclometallation is initiated by the activation process at the M=C bond and triggered by the high electron-density at the metal in the phosphido intermediates. Consistently, replacement of the trimethylsilyl (TMS) group by the electron-withdrawing 4-nitrophenyl substituent allowed for the selective cooperative P-H activation to form stable activation products.

The new bimetallic [Ru2(mu-Cl)3(CAP)6]Cl (1) and monometallic cis,cis,trans-[RuCl2(dmso)2(CAP)2] (2) complexes, bearing the water soluble cage-like phosphine CAP (1,4,7-triaza-9-phosphatricyclo[5.3.2.1]tridecane), were synthesized and characterized in solution by NMR spectroscopy and ESI-MS spectrometry. The complexes, endowed with high solubility and stability in water, were applied as catalysts for the proof-of-concept hydration of benzonitrile to benzamide in neat water at 100 °C, achieving high conversions with only 1 mol% of catalyst, both in single runs and in catalyst recycling experiments.

A half-sandwich ruthenium-p-cymene organometallic complex has been immobilized at Single Walled Carbon Nanotubes (SWNT) sidewalls through a stepwise covalent chemistry protocol. The introduction of amino groups by means of diazonium-chemistry protocols leads the grafting at the outer walls of the nanotubes. This hybrid material is active in the transfer hydrogenation of ketones to yield alcohols, using as hydrogen source 2-propanol. SWNT−NH2−Ru presents a broad scope, performing the reaction under aerobic conditions and can be recycled over 9 consecutive reaction runs without losing activity or leaching ruthenium out. Comparison of the activity with related homogeneous catalysts reveals an improved performance due to the covalent bond between the metal and the material, achieving turnover frequencies as high as 192774 h−1.

Herein we report on the development and application of chemoenzymatic Dynamic Kinetic Asymmetric Transformation (DYKAT) of α-substituted β-hydroxyketones (β-HKs), using Candida antartica lipase B (CALB) as transesterification catalyst and a ruthenium complex as epimerization catalyst. An operationally simple protocol allows for an efficient preparation of highly enantiomerically enriched α-substituted β-oxoacetates. The products were obtained in yields up to 95 % with good diastereomeric ratios.

The ruthenium-catalyzed synthesis of diarylmethane compounds was realized under exceedingly mild photoredox conditions without the use of exogenous photocatalysts. The versatility and robustness of the ruthenium-catalyzed C-H benzylation was reflected by an ample scope, including multifold C-H functionalizations, as well as transformable pyrazoles, imidates and sensitive nucleosides. Mechanistic studies were indicative of a photoactive cyclometalated ruthenium complex, which also enabled versatile C-H allylations.

The unique thermodynamic and kinetic coordination chemistry of ruthenium allows it to modulate key adverse aggregation and membrane interactions of α-synuclein (α-syn) associated with Parkinson's disease. We show that the low-toxic Ru

Iodide-bound ruthenium-JOSIPHOS complexes catalyze the redox-neutral C-C coupling of primary alcohols with methylallene (1,2-butadiene) or 1,3-butadiene to form products of anti-crotylation with good to excellent levels of diastereo- and enantioselectivity. Distinct from other methods, direct crotylation of primary alcohols in the presence of unprotected secondary alcohols is possible, enabling generation of spirastrellolide B (C9-C15) and leucascandrolide A (C9-C15) substructures in significantly fewer steps than previously possible.

International audience; The versatility of olefin metathesis is evident from its successful applications ranging from natural product synthesis to the valorization of renewable feedstocks. On the other side, flow chemistry has recently gained particular interest among the synthetic community, offering valuable alternatives to classic batch chemistry and paving the way to the development of new transformations. The application of continuous flow to olefin metathesis represents one of the most promising evolutions in the field at the interface of industrially relevant synthesis and reactor engineering, significantly improving some of the typical problems such as undesired self-reactions and ethylene-mediated catalyst de-activation. This review aims to provide a small survey covering the major aspects of those techniques which we hope may be of interest for the chemical community, but also those interested in catalysis, continuous processing, enabling technologies and reactor design.

A water-soluble bifunctional, bistate ruthenium catalyst has been developed using the 8-aminoquinoline ligand which responds to an acid-base stimuli and is catalytically active for two complementary reactions. The "Ru-amino state" is highly active for catalytic transfer hydrogenation of various aldehydes using formic acid as the hydrogen source resulting in a range of primary alcohols. On the other hand, the "Ru-amido state" is active for the acceptorless dehydrogenation of alcohols to yield carboxylate salts or ketones. The reactions can be carried out in air without an inert atmosphere and the products can be purified by simple extraction without the use of any chromatographic techniques. A range of functional groups which include electron-rich and deficient (hetero)arenes and alkenes, alkynes, halides, esters, cyano, and nitro groups, are all well tolerated, indicating excellent chemoselectivity for transfer hydrogenation.

The luminophore Ru(bpy)2 (dcbpy)2+ (bpy=2,2'-bipyridine; dcbpy=4,4'-dicarboxy-2,2'-bipyridine) is covalently linked to a chitosan polymer; crosslinking by tripolyphosphate produced Ru-decorated chitosan fibers (NS-RuCh), with a 20 : 1 ratio between chitosan repeating units and RuII chromophores. The properties of the RuII compound are unperturbed by the chitosan structure, with NS-RuCh exhibiting the typical metal-to-ligand charge-transfer (MLCT) absorption and emission bands of RuII complexes. When crosslinks are made in the presence of IrO2 nanoparticles, such species are encapsulated within the nanofibers, thus generating the IrO2 ⊂NS-RuCh system, in which both RuII photosensitizers and IrO2 water oxidation catalysts are within the nanofiber structures. NS-RuCh and IrO2 ⊂NS-RuCh have been characterized by dynamic light scattering, scanning electronic microscopy, and energy-dispersive X-ray analysis, which indicated a 2 : 1 ratio between RuII chromophores and IrO2 species. Photochemical water oxidation has been investigated by using IrO2 ⊂NS-RuCh as the chromophore/catalyst assembly and persulfate anions as the sacrificial species: photochemical water oxidation yields O2 with a quantum yield (Φ) of 0.21, definitely higher than the Φ obtained with a similar solution containing separated Ru(bpy)3 2+ and IrO2 nanoparticles (0.05) or with respect to that obtained when using NS-RuCh and "free" IrO2 nanoparticles (0.10). A fast hole-scavenging process (rate constant, 7×104 s-1 ) involving the oxidized photosensitizer and the IrO2 catalyst within the IrO2 ⊂NS-RuCh system is behind the improved photochemical quantum yield of IrO2 ⊂NS-RuCh.

Direct enantioselective hydrogenation of unsaturated compounds to generate chiral three‐dimensional motifs is one of the most straightforward and important approaches in synthetic chemistry. We realized the Ru(II)‐NHC‐catalyzed asymmetric hydrogenation of 2‐quinolones under mild reaction conditions. Alkyl‐, aryl‐ and halogen‐substituted optically active dihydro‐2‐quinolones were obtained in high yields with moderate to excellent enantioselectivities. The reaction provides an efficient and atom‐economic pathway to construct simple chiral 3,4‐dihydro‐2‐quinolones. The desired products could be further reduced to tetrahydroquinolines and octahydroquinolones., Ruthenium‐NHC‐catalyzed asymmetric hydrogenation of 2‐quinolones to simple 3,4‐dihydro‐2‐quinolones has been developed with high yields and moderate to excellent enantioselectivities under mild conditions.

A series of ruthenium alkenylacetylide complexes trans-[Ru{C≡CC(=CH2 )R}Cl(dppe)2 ] (R=Ph (1 a), c C4 H3 S (1 b), 4-MeS-C6 H4 (1 c), 3,3-dimethyl-2,3-dihydrobenzo[b]thiophene (DMBT) (1 d)) or trans-[Ru{C≡C-c C6 H9 }Cl(dppe)2 ] (1 e) were allowed to react with the corresponding propargylic alcohol HC≡CC(Me)R(OH) (R=Ph (A), c C4 H3 S (B), 4-MeS-C6 H4 (C), DMBT (D) or HC≡C-c C6 H10 (OH) (E) in the presence of TlBF4 and DBU to presumably give alkenylacetylide/allenylidene intermediates trans-[Ru{C≡CC(=CH2 )R}{C=C=C(Me)}(dppe)2 ]PF6 ([2]PF6 ). These complexes were not isolated but deprotonated to give the isolable bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH2 )R}2 (dppe)2 ] (R=Ph (3 a), c C4 H3 S (3 b), 4-MeS-C6 H4 (3 c), DMBT (3 d)) and trans-[Ru{C≡C-c C6 H9 }2 (dppe)2 ] (3 e). Analogous reactions of trans-[Ru(CH3 )2 (dmpe)2 ], featuring the more electron-donating 1,2-bis(dimethylphosphino)ethane (dmpe) ancillary ligands, with the propargylic alcohols A or C and NH4 PF6 in methanol allowed isolation of the intermediate mixed alkenylacetylide/allenylidene complexes trans-[Ru{C≡CC(=CH2 )R}{C=C=C(Me)}(dmpe)2 ]PF6 (R=Ph ([4 a]PF6 ), 4-MeS-C6 H4 ([4 c]PF6 ). Deprotonation of [4 a]PF6 or [4 c]PF6 gave the symmetric bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH2 )R}2 (dmpe)2 ] (R=Ph (5 a), 4-MeS-C6 H4 (5 c)), the first of their kind containing the dmpe ancillary ligand sphere. Attempts to isolate bis(allenylidene) complexes [Ru{C=C=C(Me)R}2 (PP)2 ]2+ (PP=dppe, dmpe) from treatment of the bis(alkenylacetylide) species 3 or 5 with HBF4 ⋅ Et2 O were ultimately unsuccessful.

The growing burden of antibiotic resistance worldwide calls for developing new classes of antimicrobial strategy. Recently years, the use of adjuvants that rescue antibiotics identified as a promising strategy for overcoming bacterial resistance. In this study, three ruthenium complexes functionalized with furan-substituted ligands([Ru(phen)2 (CAPIP)](ClO4 )2 (Ru(Ⅱ)-1), [Ru(dmp)2 (CAPIP)](ClO4 )2 (Ru(Ⅱ)-2) and [Ru(dmb)2 (CAPIP)](ClO4 )2 (Ru(Ⅱ)-3) (dmb=4,4'-dimethyl-2,2'-bipyridine, phen=1,10-phenanthroline, dmp=2,9-dimethyl-1,10-phenanthroline, CAPIP=(E)-2- (2-(furan-2-yl)vinyl)-1H-imidazo[4,5-f][1,10]phenanthroline)) were designed and synthesized. The antimicrobial activities of all compounds against S. aureus were assessed by growth inhibition assays. The MIC values of three complexes range from 0.015 to 0.050 mg/ml. Subsequently, the Ru(II)-2 complexes which exhibited strongest antibacterial activity were further tested against bacteria biofilms formation and toxin secretion. In addition, aimed to test whether ruthenium complexes have potential value as antimicrobial adjuvants, the synergism between Ru(Ⅱ)-2 and some antibiotics against S. aureus were examined through checkerboard method. Interestingly, Ru(Ⅱ)-2 could not only effectively inhibit biofilms formation of S. aureus and inhibit the hemolysin toxin secretion, but also selectivity show synergism with two common antibiotics. More importantly, mouse infection study also verified Ru(Ⅱ)-2 were highly effective against S. aureus in vivo.