Dodecacarbonyltriruthenium catalysed carbonylation of amines and hydroamidation of olefins

Dodecacarbonyltriruthenium (Ru₃(CO)₁₂) is an effective homogeneous catalyst precursor for the carbonylation of amines and hydroamidation of olefins under a carbon monoxide pressure of 40 kg cm⁻² at 120–180°C. By the carbonylation of benzylamine, N-benzylformamide was obtained in 77% yield. 1-Octene was hydroamidated with benzylamine to N-benzylnonanamide in 67% yield (the selectivity to its linear isomer was 81%). These reactions appear to include ruthenium carbamoyl complex as the common key intermediate.     

Dodecacarbonyltriruthenium catalyzed one-to-one addition of N-substituted formamide to olefins

Dodecacarbonyltriruthenium (Ru₃(CO)₁₂) showed high catalytic activity for the first one-to-one addition of N-substituted formamides to both terminal and internal olefins at 180-200°C under a carbon monoxide pressure of 20 kg cm⁻². The addition of N-metylformamide to cyclopentene afforded N-methylcyclopentanecarboxamide in 90% yield.     

Reactions of ruthenium benzylidenes with H2O to give benzaldehyde and (aqua)ruthenium complex

The second generation of Grubbs type catalyst, (PCy₃)(H₂IMes)Cl₂RuCHPh (1) undergoes the Cl replacement with CH₃CN to give cationic ruthenium carbene complexes, [(RCN)₃(H₂IMes)RuCHPh](OTf)₂ (2, R = CH₃ (a), Ph (b)) in the presence of AgOTf. The reaction of 2a with H₂O in the presence of CH₃CN gives (aqua)ruthenium complex, [Ru(H₂IMes)(NCCH₃) ₄(H₂O)](OTf)₂ (3) and benzaldehyde. Benzaldehyde is also observed in the reaction of 1 with H₂O. Plausible reaction pathways are suggested for the degradation of ruthenium benzylidenes to give benzaldehyde on the basis of the isotope labeling experiments.     

Half-sandwich trihydrido ruthenium complexes

This paper reports facile preparation of half-sandwich trihydrido complexes of ruthenium based on the reactions of the readily available precursors [Cp(R₃P)Ru(NCCH₃)₂][PF₆] with LiAlH₄. The target complexes were characterized by spectroscopic methods and X-ray structure analysis of .     

Paramagnetic ruthenium(III) cyclometallated complex. Synthesis, spectroscopic studies and electron-transfer properties

The reaction of Ru^II(PPh₃)₃X₂ (X = Cl, Br) with o-(OH)C₆H₄C(H)=N-CH₂C₆H₅ (HL) under aerobic conditions affords Ru^II(L)₂(PPh₃)₂, 1, in which both the ligands (L) are bound to the metal center at the phenolic oxygen (deprotonated) and azomethine nitrogen and Ru^III(L¹)(L²)(PPh₃), 2, in which one L is in bidentate N,O form like in complex 1 and the other ligand is in tridentate C,N,O mode where cyclometallation takes place from the ortho carbon atom (deprotonated) of the benzyl amine fragment. The complex 1 is unstable in solution, and undergoes spontaneous oxidative internal transformation to complex 2. In solid state upon heating, 1 initially converts to 2 quantitatively and further heating causes the rearrangement of complex 2 to the stable RuL₃ complex. The presence of symmetry in the diamagnetic, electrically neutral complex 1 is confirmed by ¹H and ³¹P NMR spectroscopy. It exhibits an Ru^II → L, MLCT transition at 460 nm and a ligand based transition at 340 nm. The complex 1 undergoes quasi-reversible ruthenium(II)—ruthenium(III) oxidation at 1.27V vs. SCE. The one-electron paramagnetic cyclometallated ruthenium(III) complex 2 displays an L → Ru^III, LMCT transition at 658 nm. The ligand based transition is observed to take place at 343 nm. The complex 2 shows reversible ruthenium(III)—ruthenium(IV) oxidation at 0.875V and irreversible ruthenium(III)—ruthenium(II) reduction at −0.68V vs. SCE. It exhibits a rhombic EPR spectrum, that has been analysed to furnish values of axial (6560 cm⁻¹) and rhombic (5630 cm⁻¹) distortion parameters as well as the energies of the two expected ligand field transitions (3877 cm⁻¹ and 9540 cm⁻¹) within the t₂ shell. One of the transitions has been experimentally observed in the predicted region (9090 cm⁻¹). The first order rate constants at different temperatures and the activation parameter ΔH^#/ΔS^# values of the conversion process of 1 → 2 have been determined spectrophotometrically in chloroform solution.     

Application of ruthenium catalyzed oxidation of [tris(2-aminoethyl)amine] in trace determination of ruthenium in environmental water samples

The ruthenium catalyzed oxidation of tris(2-aminoethyl)amine (TREN) by hexacyanoferrate(III) has been utilized for the development of a new and sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III). The reaction was followed spectrophotometrically by the decrease in absorbance at 420nm (lambda(max) of [Fe(CN)(6)](3-)). The CKM developed utilizes fixed time procedure under optimum reaction conditions where the change in absorbance (DeltaA(t)) versus ruthenium(III) concentrations is plotted. The calibration curve recommended for the method is linear in the concentration range 10.11-252.67ngml(-1) with very good accuracy and reproducibility and a maximum error 2.20%. The detection limits of the method for ruthenium(III) corresponding to 10, 15 and 20min are 8.02, 5.03 and 3.15ngml(-1), respectively. The ruthenium(III) has also been determined in the presence of several other interfering and non-interfering cations and anions and no foreign ions interfered in the determination of ruthenium(III) up to five-fold higher concentration of the foreign ions tested. The method is highly sensitive, selective and stable. It has successfully been applied for the determination of trace ruthenium(III) in some synthetic and environmental water samples. A review of most of the published catalytic kinetic and some other important methods for the determination of ruthenium has also been presented.     

Two-dimensional ruthenium nanoparticles between graphite layers: The effect of reduction temperature

A mixture of graphite powder and ruthenium chloride (III) anhydrous was treated at 723 K under 0.3 MPa chlorine for 3 days, followed by reduction under 40 kPa of hydrogen for 1 h to produce ruthenium metal particles intercalated between graphite layers (Ru-GIC). The structures of ruthenium particles depended on the reduction temperatures. Sheet-like ruthenium particles with 1–3 nm thickness and 10 to several hundred nm width containing numerous irregularly shaped holes with round edge, were formed by reduction at 573 K. A Ru-GIC sample treated at 653 K possessed two-dimensional ruthenium nanosheets with hexagonal holes (straight lines intersect at an angle of 120°) in a similar range of thickness and width. On the other hand, Ru-GIC samples reduced at 773 and 823 K showed two-dimensional plate morphology with a thickness of 1–4 nm. In addition, ruthenium nanoparticles supported on the graphite surface (Ru/Gmix) were also prepared from a slurry of ruthenium chloride (III) hydrate and graphite powder by impregnation and hydrogen reduction. The ruthenium particles in Ru/Gmix were spherical at about 3.6 nm, and the reduction temperature did not affect their particles size. Both Ru-GIC and Ru/Gmix samples were evaluated for cinnamaldehyde (CAL) hydrogenation in supercritical carbon dioxide solvent at 323 K, and they were active to produce cinnamyl alcohol (COL) and hydrocinnamaldehyde (HAL). However, Ru-GIC samples showed higher COL selectivity than Ru/Gmix prepared at the same reduction temperature, and COL selectivity over Ru-GIC increased with the reduction treatments at 773 and 823 K.     

Thermal stability and photostability of water solutions of sulfophthalocyanines of Ru(II), Cu(II), Ni(II), Fe(III) and Co(II)

The thermal and photochemical stabilities were investigated for tetrasulfophthalocyanines of Cu, Co, Ni, Fe and Ru (MPcS) and for two monosulfophthalocyanines of Ru, either without (RuPcS1) or with the coordination of two units of DMSO in apical positions ([RuPcS1(DMSO)₂]DMSO). The thermal degradation of all of the studied complexes never showed the formation of spectroscopically detectable intermediates. CuPcS was the most stable complex, while all of the Ru-sulfophthalocyanines were particularly prone to thermal degradation. Photodegradation showed a better selectivity, and as with thermal degradation, the order of reactivity goes from the most stable CuPcS, to the least stable Ru-sulfophthalocyanines (RuPcS, RuPcS1 and [RuPcS(DMSO)₂]DMSO). In particular, when the RuPcS complex was irradiated, a stable intermediate was detected that had an absorption band at 532 nm and a mass spectrum attributable to the tetrasulfophthalocyanine from oxidative ring cleavage by the action of the singlet oxygen formed via ¹*RuPcS photosensitization. The most probable molecular formula demonstrates a new complex, with a cleaved ring containing an -NO group and two -OH groups that are all bonded at the two extremities of the open-chain molecule.     

Layered ruthenium hexagonal perovskites: The new series [Ba2Br2−2x(CO3)x][Ban+1RunO3n+3] with n=2, 3, 4, 5

Single crystals of the title compounds were prepared by solid state reactions from barium carbonate and ruthenium metal using a BaBr₂ flux and investigated by X-ray diffraction method using Mo(Kα) radiation and a Charge Coupled Device (CCD) detector. A structural model for the term n=2, Ba₅Ru₂Br₂O₉ (1) was established in the hexagonal symmetry, space group P6₃/mmc, a=5.8344(2) Å, c=25.637(2) Å, Z=2. Combined refinement and maximum-entropy method (MEM) unambiguously show the presence of CO₃²⁻ ions in the three other compounds (2, 3, 4). Their crystal structures were solved and refined in the trigonal symmetry, space group , a=5.8381(1) Å, c=15.3083(6) Å for the term n=3, Ba₆Ru₃Br_1.54(CO₃)_0.23O₁₂ (2), and space group , a=5.7992(1) Å, c=52.866(2) Å and a=5.7900(1) Å, c=59.819(2) Å for the terms n=4, Ba₇Ru₄Br_1.46(CO₃)_0.27O₁₅ (3), and n=5, Ba₈Ru₅Br_1.64(CO₃)_0.18O₁₈ (4), respectively. The structures are formed by the periodic stacking along [0 0 1] of (n+1) hexagonal close-packed [BaO₃] layers separated by a double layer of composition [Ba₂Br_2−2x(CO₃)_x]. The ruthenium atoms occupy the n octahedral interstices created in the hexagonal perovskite slabs and constitute isolated dimers Ru₂O₉ of face-shared octahedra (FSO) in 1 and isolated trimers Ru₃O₁₂ of FSO in 2. In 3 and 4, the Ru₂O₉ units are connected by corners either directly (3) or through a slab of isolated RuO₆ octahedra (4) to form a bidimensional arrangement of RuO₆ octahedra. These four oxybromocarbonates belong to the family of compounds formulated [Ba₂Br_2−2x(CO₃)_x][Ba_n+1Ru_nO_3n+3] where n represents the thickness of the octahedral string in hexagonal perovskite slabs. These compounds are compared to the oxychloride series.     

Ru(Ⅲ)-KIO4-偶氮氯膦pA褪色反应用于痕量钌了的催化光度测定

酸性介质中痕量Ｒｕ（Ⅲ）的存在对高碘酸钾氧化偶氯膦ｐＡ的褪色反应有明显的催化作用。此文研究了褪色反应的最佳条件,其Ｒｕ（Ⅲ）的检出限为５μｇ．Ｌ＾－１,钌在５～３２μｇ．Ｌ＾－１范围内符合比耳定律,由此建立了痕量钌的催化光度分析法,方法可直接在水相中进行,用于贵金属精矿中钌的测定,结果满意。     

Reactions of Ru3(CO)12 with Diphosphenes — A New Route to 50‐Electron Ru3P2 nido‐Clusters

The reaction of the symmetric diphosphene 2, 4, 6‐(CF₃)₃‐C₆H₂‐P=P‐C₆H₂‐2, 4, 6‐(CF₃)₃ 4 with Ru₃(CO)₁₂ led to the 50‐electron Ru₃P₂ nido‐cluster Ru₃(CO)₉[μ‐P‐C₆H₂‐2, 4, 6‐(CF₃)₃]₂ 5 , which in solution at room temperature displays hindered rotation of the aromatic rings about the C(aryl)—P bonds. The structure of 5 was determined by X‐ray crystal structure analysis; its Ru₃P₂ centre forms a distorted square pyramid with one ruthenium atom at the apex. One of the two C₆H₂(CF₃)₃ groups is also appreciably distorted. Temperature‐dependent ¹⁹F NMR studies of the [A₃M₃X]₂ spin system (A = M = CF₃, X = ³¹P) of 5 indicated a rotational barrier ΔG^≠ of 82.3 kJ mol^‐1 at 141 °C. The same Ru₃P₂ core was obtained by the reaction of the unsymmetric diphosphene Mes*‐P=P‐Mes 11 with Ru₃(CO)₁₂; hindered rotation about the C(aryl)—P bonds was also observed, in this case.     

Ruthenium(II)-catalyzed para-selective CH difluoroalkylation of aromatic aldehydes and ketones using transient directing groups

A Ru(II)-catalyzed para-difluoroalkylation of aromatic aldehydes and ketones with a transient directing group has been developed. It utilizes less expensive ruthenium catalysts and allows facile access to challenging difluoroalkylated aldehydes. The mechanism studies suggest that the distinct coordination mode of ruthenium complex with imine moieties is responsible for para-selectivity.     

Synthesis and Catalytic Activity of a Two-core Ruthenium Carbene Complex: a Unique Catalyst for Ring Closing Metathesis Reaction

The reaction of a ruthenium carbide complex RuCl2(C:)(PCy3)2 with [H(Et2O)x]+[BF4]– at a molar ratio of 1:2 produced a two-core ruthenium carbene complex, {[RuCl(=CHPCy3)(PCy3)]2(μ-Cl)3}+·[BF4]–, in the form of a yellow-green crystalline solid in a yield of 94%. This two-core ruthenium complex is a selective catalyst for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed for N-substrates when the two-core ruthenium complex was used as the catalyst at an elevated temperature(137 °C), indicating that the complex is a chemo-selective catalyst for ring closing metathesis reactions.     

RuS4Cl12 und Ru2S6Cl16, zwei neue Ruthenium(II)‐Komplexe mit SCl2‐Liganden

RuS₄Cl₁₂ and Ru₂S₆Cl₁₆, Two New Ruthenium(II) Complexes with SCl₂ Ligands Ru powder was reacted with SCl₂ in closed silika ampoules at 140 °C. From the black solution three compounds RuS₄Cl₁₂ 1 , Ru₂S₆Cl₁₆ 2 , and Ru₂S₄Cl₁₃ 3 could be crystallized and characterized by x ray analysis. Black crystals of 1 (monoclinic, a = 9.853(1) Å, b = 11.63(1) Å, c = 15.495(1) Å, β = 105.23(1)°, space group P2₁/c, z = 4) are identified as Trichlorsulfonium‐tris(dichlorsulfan)trichloro‐ruthenat(II) SCl₃[RuCl₃(SCl₂)₃]. In the structure the complex anions fac‐[RuCl₃(SCl₂)₃]^– and the cations [SCl₃]⁺ are connected to ion pairs by three chlorine bridges. The brown crystals of 2 (triclinic, a = 7.754(2) Å, b = 7.997(2) Å, c = 10.708(2) Å, α = 103.74(3)°, β = 98.44(3)°, γ = 108.58(3)°, space group P‐1, z = 1) contain the binuclear complex Bis‐μ‐chloro‐dichloro‐hexakis(dichlorsulfan)‐diruthenium(II), (SCl₂)₃ClRu(μ‐Cl)₂RuCl(SCl₂)₃ with two fac‐RuCl₃(SCl₂)₃‐units connected by two chlorine bridges. 3 was identifyed as a known mixed valence Ru(II,III) binuclear complex [Cl₂(SCl₂)Ru(μ‐Cl)₃Ru(SCl₂)₃]. The vibrational spectra and the thermal behaviour of the compounds are discussed.     

Ru(Ⅲ)-KIO_4-偶氮氯膦pA褪色反应用于痕量钌的催化光度测定

酸性介质中痕量 Ru( )的存在对高碘酸钾氧化偶氮氯膦 p A的褪色反应有明显的催化作用。此文研究了褪色反应的最佳条件 ,其 Ru( )的检出限为 5μg· L-1,钌在 5～ 32μg· L-1范围内符合比耳定律。由此建立了痕量钌的催化光度分析法。方法可直接在水相中进行 ,用于贵金属精矿中钌的测定 ,结果满意     

Oxidant-free oxidation: ruthenium catalysed dehydrogenation of alcohols

The oxidation of alcohols has been achieved using Grubbs’ catalyst or a ruthenium p-cymene complex without the presence of an added oxidant.     

Preparation and molecular structure of a pyrazolyl-ruthenium complex, Ru{C3H2NN(SO2tol)}(dppe)Cp*

The reaction between RuCl(dppe)Cp* and Me₃SiCCC(SiMe₃)NNHTs has given the pyrazole derivative (1), which was characterised by a single-crystal X-ray structure determination. Complex 1 is probably formed by attack of the NTs group on the π-complexed desilylated alkyne, with concomitant loss of a proton.     

A hydroxyquinoline-appended ruthenium(II)-polypyridyl complex that induces and stabilizes G-quadruplex DNA

A polypyridyl ruthenium(II) complex with hydroxyquinoline-derived ligand has been synthesized and characterized. The ability to act as telomeric quadruplex inducer and stabilizer, and quadruplex-binding properties of the complex have been evaluated by absorption and emission analyses, fluorescent intercalator displacement (FID) titrations, circular dichroism (CD) spectroscopy, polymerase chain reaction (PCR) stop assay, color reaction studies, fluorescence resonance energy transfer (FRET) melting assay, Job plot, and molecular modeling. Observations revealed that the complex could well induce and stabilize the formation of antiparallel G-quadruplex of telomeric DNA in the presence or absence of metal cations, and showed superior G-quadruplex selectivity over duplex DNA with remarkable ΔT_m value of 18.0?°C even at 50-fold excessive supplies of calf thymus (ct) DNA. The complex exhibited high interaction affinity of 2.56?×?10⁶ M^?1 with G-quadruplex DNA and evident luminescence enhancements of 3.1 and 4.2 times for quadruplex binding in Na⁺ and K⁺ buffer, respectively. In addition, the 1:1 [quadruplex]/[complex] binding mode ratio was determined. The results suggest that the complex can be developed as potential anticancer reagent through binding and stabilization of G-quadruplex DNA.

     

Hydrogen photoevolution from water-methanol on Ru/TiO2

Summary In situ ruthenium photodeposition on anatase TiO₂ was found to be an efficient method of obtaining Ru/TiO₂ powders highly active in hydrogen photoevolution from water-methanol. The efficiency of the catalyst was higher when the TiO₂ powder was subjected to a cation exchange prior to illumination in water-methanol. Reaction conditions were optimized; it was found that the most active sample was TiO₂ covered with 0.75 wt% Ru. Anatase TiO₂ itself was found to be porous with an average cylindrical pore radius of 37 Å. SEM and electron microprobe analysis showed that the photodeposition of ruthenium on the porous substrate resulted in a nonhomogeneous distribution on the TiO₂ surface. The size of ruthenium islets seems to influence the stability of Ru/TiO₂ catalysts in hydrogen photoevolution from water-methanol.

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Photoevolution von Wasserstoff aus Wasser-Methanol auf Ru/TiO₂

Zusammenfassung Es wurde festgestellt, daß diein situ Photodepositierung von Ruthenium auf Anatas-TiO₂ eine effiziente Methode darstellt, um Ru/TiO₂-Pulver herzustellen, das eine hohe Aktivität bei der Photoevolution von Wasserstoff aus Wasser-Methanol besitzt. Die Effizienz des Katalysators war höher, wenn das TiO₂-Pulver vor der Bestrahlung einem Kationenaustausch unterworfen wurde. Die Reaktionsbedingungen wurden optimiert; TiO₂, bedeckt mit 0.76 Gew% Ru, zeigte sich als aktivster Katalysator. Anatas-TiO₂ selbst erwies sich als porös mit einem mittleren zylindrischen Porenradius von 37 Å. Mittels SEM und Mikrosondenanalyse wurde festgestellt, daß die Photodepositierung von Ruthenium auf dem porösen Substrat eine nichthomogene Verteilung auf der TiO₂-Oberfläche ergibt. Das Ausmaß und die Größe der Ruthenium-Anhäufungen scheinen die Stabilität von Ru/TiO₂-Katalysatoren bei der Photoevolution von Wasserstoff aus Wasser-Methanol zu beeinflussen.