Ruthenium‐Catalyzed Intramolecular Allylic Dearomatization/Migration Reaction of Indoles and Pyrroles

An efficient synthesis of polycyclic indole and pyrrole derivatives via a ruthenium‐catalyzed intramolecular allylic dearomatization/migration reaction has been developed. This method features wide substrate scope, mild reaction conditions, and an operationally simple procedure. The capture of the spiro intermediate provides solid evidence for the dearomatization/migration reaction pathway.

     

Enantioselective Synthesis of α‐Trifluoromethyl Arylmethylamines by Ruthenium‐Catalyzed Transfer Hydrogenation Reaction

A simple combination of dichloro(para‐cymene)ruthenium(II) dimer, a chiral amino alcohol and isopropyl alcohol allowed for in‐situ generation of the bifunctional catalyst responsible for the transfer hydrogenation reaction of trifluoromethyl ketimines in excellent yields with high enantioselectivities (up to 93% ee). Herein, we describe the optimization, scope, limitations, and applications of the method.

     

Highly Active Metastable Ruthenium Nanoparticles for Hydrogen Production through the Catalytic Hydrolysis of Ammonia Borane

Late transition metal nanoparticles (NPs) with a favorably high surface area to volume ratio have garnered much interest for catalytic applications. Yet, these NPs are prone to aggregation in solution, which has been mitigated through attachment of surface ligands, additives or supports; unfortunately, protective ligands can severely reduce the effective surface area on the NPs available for catalyzing chemical transformations. The preparation of ‘metastable’ NPs can readily address these challenges. We report herein the first synthesis of monodisperse metastable ruthenium nanoparticles (RuNPs), having sub 5 nm size and an fcc structure, in aqueous media at room temperature, which can be stored for a period of at least 8 months. The RuNPs can subsequently be used for the catalytic, quantitative hydrolysis of ammonia‐borane (AB) yielding hydrogen gas with 21.8 turnovers per min at 25 °C. The high surface area available for hydrolysis of AB on the metastable RuNPs translated to an E_a of 27.5 kJ mol^‐1, which is notably lower than previously reported values for RuNP based catalysts.     

Graphene–Ruthenium Complex Hybrid Photodetectors with Ultrahigh Photoresponsivity

The maximum responsivity of a pure monolayer graphene‐based photodetector is currently less than 10 mA W^?1 because of small optical absorption and short recombination lifetime. Here, a graphene hybrid photodetector functionalized with a photoactive ruthenium complex that shows an ultrahigh responsivity of ≈1 × 10⁵ A W^?1 and a photoconductive gain of ≈3 × 10⁶ under incident optical intensity of the order of sub‐milliwatts is reported. This responsivity is two orders of magnitude higher than the precedent best performance of graphene‐based photodetectors under a similar incident light intensity. Upon functionalization with a 4‐nm‐thick ruthenium complex, monolayer graphene‐based photodetectors exhibit pronounced n‐type doping effect due to electron transfer via the metal?ligand charge transfer (MLCT) from the ruthenium complex to graphene. The ultrahigh responsivity is attributed to the long lifetime and high mobility of the photoexcited charge carriers. This approach is highly promising for improving the responsivity of graphene‐based photodetectors.     

Solid state synthesis of hydrous ruthenium oxide for supercapacitors

A novel solid state route has been successfully developed for the synthesis of nano-scale hydrous ruthenium oxide (denoted as RuO₂·xH₂O). The procedure involves directly mixing RuCl₂·xH₂O with alkali to form RuO₂·xH₂O in a mortar at room temperature. Transmission electron microscopy (TEM) and N₂ adsorption–desorption measurement indicate that the RuO₂·xH₂O particle is approximately 30–40 nm with mesoporous structure. The crystalline structure and the electrochemical properties of RuO₂·xH₂O have been systematically explored as a function of annealing temperature. At lower temperatures, the RuO₂·xH₂O powder was found in an amorphous phase and the maximum capacitance of 655 F g⁻¹ was obtained by annealing at 150 °C. Higher temperatures (exceeding 175 °C) presumably converted amorphous phase into crystalline one and the corresponding specific capacitance dropped rapidly from 547 F g⁻¹ at 175 °C to 87 F g⁻¹ at 400 °C. Also, the dependence of electrochemical performance on annealing conditions of RuO₂·xH₂O was investigated by electrical impedance spectroscopy (EIS) study.     

Dye sensitized photovoltaic cells: Attaching conjugated polymers to zwitterionic ruthenium dyes

The synthesis of a zwitterionic ruthenium dye that binds to anatase surfaces and has a built-in functionality that allows for the attachment of a conjugated polymer chain is presented. The system was found to adsorb on the surface of anatase anchored by the ruthenium dye. Two types of devices were prepared: standard photoelectrochemical (PEC) solar cells and polymer solar cells. The PEC solar cells employed a sandwich geometry between TiO₂ nanoporous photoanodes and Pt counter electrodes using LiI/I₂ in CH₃CN as an electrolyte. The polymer solar cells employed planar anatase electrodes and the complex was adsorbed onto the surface before evaporation of gold electrodes. Alternative devices were obtained by spincoating of the polymer solution onto PEDOT:PSS covered indium-doped tin oxide substrates. PEC solar cells gave the best results and the main finding was that the polymer chain served as a light harvesting antenna for the ruthenium dye.     

Dissolution and Separation of Ruthenium in Borosilicate Glass

The behavior of ruthenium oxide (RuO₂) in aluminoborosilicate glass used for the stabilization of nuclear waste was investigated. It was found that 0.025 mass% RuO₂ dissolved as Ru⁴⁺ in the glass at 1400°C, which caused the glass to turn yellow. When the RuO₂ amount was 0.05 mass%, needle-shaped crystals formed in the glass during slow cooling. If the added amount exceeded 0.1 mass% and the cooling rate was slow, it separated rapidly and the glass became pale after cooling. No dissolution of ruthenium was detectable after melting at 1200°C.     

钌离子催化氧化法研究沥青质经加氢处理后的变化

 利用钌离子催化氧化方法研究了渣油中沥青质的化学结构，定量测定了与沥青质芳香核相连的烷基侧链和烷基桥链的分布，推断了沥青质中芳香环系的缩合形式，讨论了沥青质组分在加氢处理过程中的结构变化规律。结果表明，渣油组分中都存在C1～C27的烷基侧链，并且主要是正构烷基侧链，也存在与两个芳香核相连接的C2～C16烷基桥链，它们的浓度随链长增加而下降。沥青质的氧化产物中检测出从邻苯二甲酸到苯六甲酸的一系列苯多甲酸。沥青质芳香核结构中存在着渺位缩合、迫位缩合和联苯结构，其中联苯结构较少。沥青质可以看作纯粹的迫位缩合。随着加氢处理深度的增加，沥青质组分的化学结构发生变化，芳香结构较大的芳香核在沥青质中富集，使得沥青质组分中的芳香结构逐渐增多，芳香核缩合程度逐渐增加。