Chemistry Of Ruthenium Research Articles

Electrochemical recovery of ruthenium via carbon black nano-impacts

The recovery of ruthenium from low-concentration solutions poses a significant challenge due to its scarcity and rising economic value, and nano-impact electrochemistry has emerged as a promising method for efficient recovery of critical metals from solution through deposition during impacts of non-metallic nanoparticles. In this study, we investigate the redox chemistry of ruthenium on carbon black via the impact technique and demonstrate the ability to recover ruthenium from solution. The reduction (electrodeposition) and oxidation of Ru3+ ions in solution onto carbon black nanoparticles can be observed during nano-impacts with the respective onset potentials of these redox processes agreeing with those obtained from solution voltammetry. Upscaled experiments focusing on the electroreduction process, led to the formation of RuOx deposits, confirmed through scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) analysis, X-ray photoelectron spectroscopy (XPS) analysis, and thermogravimetric analysis (TGA). Under partially-optimised conditions, >90 % recovery of Ru(III) from a 1 mM solution was achieved in ca. 8 h.

Electrochemistry of different ruthenium polypyridine complexes

In search for antitumor metal-based drugs that would mitigate the severe side-effects of cisplatin, Ru(II) complexes are gaining increasing recent interest. Their cytotoxic effect is widely known, however mechanism of action, solution behavior, redox reactions within biological system are still focus of the new studies. Various experiments and approach techniques are used to better understand ruthenium chemistry. In this order their biological activity and the availability of reduction potential in the biological medium, it is necessary to know their electrochemical redox behavior and properties. In this work, we report the electrochemical activity on synthesized and characterized (1H- and 13C NMR, FT-IR, MS) half-sandwich organometallic Ru(II) complexes of the general formula [Ru(η6-arene)(XY)Cl](PF6) where arene = benzene, toluene or p-cymene and XY = bidentates: dipyrido[3,2-a:2′,3′-c]phenazine (dppz derivatives) or 2-(9-anthryl)-1H-imidazo[4,5-f][1,10]phenanthroline (aip), which are bound to Ru(II) via two phenanthroline-N atoms in a characteristic “piano-stool” configuration of Ru(II)-arene complexes – as confirmed by vibrational and NMR spectra. It is shown that selected complexes can be divided in four groups, based on their electrochemical behavior. These behaviors are correlated with their structure and nature of ligands.

Superb ruthenium(ii) complex melody: Uncovering its hidden catalytic and biological properties

Aliphatic/aromatic nitrogen-substituted ligands have a very important role in ruthenium chemistry. Polydentate ligands with N-substituted pyridine rings are notable for their ability to easily modify the electronic and steric properties of ruthenium. In this study, the catalytic and biological activities of the [RuCl2(NNN)(CH3CN)] (NNN: 2,6-di(1H-pyrazol-3-yl)pyridine)) complex were examined for two different applications. Firstly, the superb Ru(II) complex was used to catalyze the methanolysis of NaBH4, and its initial rate was calculated as 69360 mLH2min−1gcat−1. Secondly, the biological activities of the superb Ru(II) complex were examined. Accordingly, it was determined that this homogeneous complex showed anti-microbial activity on all bacteria used in the study, among the Gram-positive bacteria used in the study, the best result belongs to the Bacillus cereus EMC 19 bacterium with 8 mm, while among the Gram-negative bacteria, the best zone diameter belongs to the Pseudomonas aeruginosa DSM 50071 bacterium with 5 mm. However, it was observed that zone diameters varied between 8 mm and 3 mm. Compared to the control group, it was determined that 0.25 mg/mL concentration had 94.87%, 0.5 mg/mL concentration 96.10%, 1 mg/mL concentration 96.50%, and 2 mg/mL concentration 97.09% cytotoxic activity on the SH-SY5Y cell line. it was determined that all doses of the superb Ru(II) complex used in the study showed anti-cancer activity, but the anticancer activity shown at low doses was statistically more significant at the p < 0.05 level.

Recent trends in the design and delivery strategies of ruthenium complexes for breast cancer therapy.

As the most frequent and deadly type of cancer in women, breast cancer has a high propensity to spread to the brain, bones, lymph nodes, and lungs. The discovery of cisplatin marked the beginning of the development of anticancer metal-based medications, although the drug's severe side effects have limited its usage in clinical settings. The remarkable antimetastatic and anticancer activity of different ruthenium complexes such as NAMI-A, KP1019, KP1339, etc. reported in the 1980s has bolstered the discovery of ruthenium complexes with various types of ligands for anticancer applications. The review meticulously elucidates the cytotoxic and antimetastatic potential of reported ruthenium complexes against breast cancer cells. Notably, arene-based and cyclometalated ruthenium complexes emerge as standout candidates, showcasing remarkable potency with notably low IC50 values. These findings underscore the promising therapeutic avenues offered by ruthenium-based compounds, particularly in addressing the challenges posed by conventional treatments in refractory or aggressive breast cancer subtypes. Moreover, the review comprehensively integrates a spectrum of ruthenium complexes, spanning traditional metal complexes to nano-based formulations and light-activated variants, underscoring the versatility and adaptability of ruthenium chemistry in breast cancer therapy.

Customizable Low-Friction Tough Hydrogels for Potential Cartilage Tissue Engineering by a Rapid Orthogonal Photoreactive 3D-Printing Design.

Hydrogels have demonstrated wide applications in tissue engineering, but it is still challenging to develop strong, customizable, low-friction artificial scaffolds. Here, we report a rapid orthogonal photoreactive 3D-printing (ROP3P) strategy to achieve the design of high-performance hydrogels in tens of minutes. The orthogonal ruthenium chemistry enables the formation of multinetworks in hydrogels via phenol-coupling reaction and traditional radical polymerization. Further Ca2+-cross-linking treatment greatly improves their mechanical properties (6.4 MPa at a critical strain of 300%) and toughness (10.85 MJ m-3). The tribological investigation reveals that the high elastic moduli of the as-prepared hydrogels improve their lubrication (∼0.02) and wear-resistance performances. These hydrogels are biocompatible and nontoxic and promote bone marrow mesenchymal stem cell adhesion and propagation. The introduction of 1-hydroxy-3-(acryloylamino)-1,1-propanediylbisphosphonic acid units can greatly enhance their antibacterial property to kill typical Escherichia coli and Staphylococcus aureus. Moreover, the rapid ROP3P can achieve hydrogel preparation in several seconds and is readily compatible with making artificial meniscus scaffolds. The printed meniscus-like materials are mechanically stable and can maintain their shape under long-term gliding tests. It is anticipated that these high-performance customizable low-friction tough hydrogels and the highly efficient ROP3P strategy could promote further development and practical applications of hydrogels in biomimetic tissue engineering, materials chemistry, bioelectronics, and so on.

α‐Synuclein as a Target for Metallo‐Anti‐Neurodegenerative Agents

AbstractThe 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 RuIII complex trans‐[ImH][RuCl4(Me2SO)(Im)] (NAMI‐A) has dual inhibitory effects on both aggregation and membrane interactions of α‐syn with submicromolar affinity, and disassembles pre‐formed fibrils. NAMI‐A abolishes the cytotoxicity of α‐syn towards neuronal cells and mitigates neurodegeneration and motor impairments in a rat model of Parkinson's. Multinuclear NMR and MS analyses show that NAMI‐A binds to residues involved in protein aggregation and membrane binding. NMR studies reveal the key steps in pro‐drug activation and the effect of activated NAMI‐A species on protein folding. Our findings provide a new basis for designing ruthenium complexes which could mitigate α‐syn‐induced Parkinson's pathology differently from organic agents.

α-Synuclein as a Target for Metallo-Anti-Neurodegenerative Agents.

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 RuIII complex trans-[ImH][RuCl4 (Me2 SO)(Im)] (NAMI-A) has dual inhibitory effects on both aggregation and membrane interactions of α-syn with submicromolar affinity, and disassembles pre-formed fibrils. NAMI-A abolishes the cytotoxicity of α-syn towards neuronal cells and mitigates neurodegeneration and motor impairments in a rat model of Parkinson's. Multinuclear NMR and MS analyses show that NAMI-A binds to residues involved in protein aggregation and membrane binding. NMR studies reveal the key steps in pro-drug activation and the effect of activated NAMI-A species on protein folding. Our findings provide a new basis for designing ruthenium complexes which could mitigate α-syn-induced Parkinson's pathology differently from organic agents.

Insights into the substitutional chemistry of La1−xSrxCo1−yMyO3 (M = Pd, Ru, Rh, and Pt) probed by in situ DRIFTS and DFT analysis of CO oxidation

We report the detailed surface chemistry of platinum, palladium, rhodium, and ruthenium substituted into lanthanum strontium cobaltate perovskite catalysts toward CO oxidation. The catalysts were synthesized by the solution combustion method and characterized in detailed using a series of techniques. To explore the effect of noble metal ion substitution on CO oxidation, surface intermediates were probed by operando diffuse reflectance infrared Fourier transform spectroscopy. It was recognized that La1−xSrxCo1−yRhyO3 and La1−xSrxCo1−yPdyO3 show the best activities for the reaction. DFT calculations were set up to unravel the details of the surface phenomena responsible for altering the CO oxidation activity upon noble metal ion substitution. The computational analysis conclusively demonstrated the experimentally hypothesized role of surface carbonate formation and revealed the altered mechanism for CO oxidation over the synthesized perovskites upon noble metal ion substitution.

An Overview of Ruthenium-Catalyzed Multicomponent Reactions

Abstract: In multicomponent reactions (MCRs), highly functionalized compounds can be formed through the reaction between three or more reactants in a one-pot manner. These reactions provide products through the utilization of lesser amounts of energy, time, and effort. MCRs also possess advantages like the generation of lesser waste materials. Fewer resources are needed, high convergence etc. In terms of energy economy and atom economy, MCRs are superior to multistep synthesis. A wide range of products can be acquired by combining the reagents in a variety of ways and thus, MCRs became popular in various fields such as catalysis, pharmaceutical chemistry, material science, agrochemistry, fine chemistry and so on. MCRs obey the principles of green chemistry because these approaches are simple and ecofriendly. MCR is an unrivalled synthetic technique and has been used by chemists at an accelerating rate in recent years. Ruthenium catalysts are cheap in comparison to palladium and rhodium, and generally show high activity. Ru possesses wide-ranging oxidation states due to its 4d7 5s1 electronic configuration. Numerous organic reactions are catalyzed by ruthenium, which are utilized in forming a wide range of pharmaceuticals and natural products, with biological importance. Minimum amounts of waste materials are formed in most of the ruthenium-catalyzed reactions; hence, ruthenium catalysis paves the way to environmentally benign protocols. Ruthenium chemistry has had a really big impact on organic synthesis in recent years and it is now on par with palladium in terms of relevance. The developments in the field of ruthenium-catalyzed multicomponent reactions are highlighted in this review, covering the literature up to 2021.

Ruthenium speciation in radioactive wastes and state-of-the-art strategies for its recovery: A review

• Recovery of 106 Ru from spent nuclear fuel is required for its use in ocular cancer therapy. • Ruthenium speciation decides its separation strategy. So it is discussed in detail. • Ru recovery from acidic and alkaline radioactive feeds is given in detail. • Ru recovery by solvent extraction, precipitation and ion exchange is summarized. • Special mention is made to ion-exchange based separation methods. Ruthenium, mainly 106 Ru, is one of the notorious fission products present in the radioactive wastes. In view of its complex chemistry, it gets partitioned into various processing streams during the radioactive waste management steps. Also, due to the volatile nature of its tetraoxide, RuO 4 , it gets deposited in the process pipelines and stacks. Attempts have been made by various researchers, over the years, to separate radio-ruthenium from radioactive feeds including the acidic high level liquid waste (HLLW) as well as the alkaline low level liquid waste (LLLW) or intermediate level liquid wastes (ILLW). Solvent extraction, precipitation, ion-exchange, etc are some of the commonly employed techniques used for the separation of radio-ruthenium from radioactive feeds. The present review article gives a state-of-the-art of the separation of radio-ruthenium from radioactive waste feeds based on Ruthenium speciation in the system. Most of the published literature involves synthetic feeds rather than actual radioactive wastes. Nevertheless, the published data gives very important information on how to separate radio-ruthenium from different types of radioactive feeds. The aqueous chemistry of Ruthenium is quite complex due to the co-existence of different ionic species of different oxidation states. In view of this, this review article begins with a brief summary on the aqueous chemistry of Ruthenium in acidic as well as alkaline feeds and subsequently its separation from these solutions were discussed using various techniques under the light of its speciation.

Ruthenium complexes of N/O/S based multidentate ligands: Structural diversities and catalysis perspectives

Recent time has witnessed remarkable advances in the coordination and the organometallic chemistry of ruthenium. Such a growth is primarily due to the propensity of ruthenium complexes to drive assorted organic transformations. However, most of the catalytic reactions require tuning of the electronic as well as the steric characteristics at the metal center to control the product outcome. In this context, designing of the multidentate ligands and their coordination modes are critical parameters. This review article highlights selected ruthenium complexes supported with a related class of multidentate ligands containing amide, oxalamide, azocarboxamide and acylthiourea functional groups. Such multidentate ligands are shown to coordinate a ruthenium center by a combination of N/O/S donor groups while exhibiting versatile coordination modes. Both the donor group(s) and the coordination mode(s) of ligands are shown to impact the subsequent catalytic reactions of the resultant ruthenium complexes.

Coordination Chemistry of Ruthenium

Ruthenium is one of the rare elements that belongs to the platinum group metals. Ruthenium is very effective hardener for platinum and palladium. Well studied coordination and organometallic chemistry of ruthenium results in a various varieties of compounds. There are various features of ruthenium such as oxidation states, coordination numbers and geometries. Ruthenium compounds have various applications and also have low toxicity and they are ideal for the catalytic synthesis of drugs. The field of ruthenium chemistry is very broad and is extremely diverse in the field of catalysis and medicinal chemistry. This review article shows a classical general chemistry of ruthenium compounds.

Understanding of [RuL(ONO)]n+ acting as nitric oxide precursor, a theoretical study of ruthenium complexes of 1,4,8,11-tetraazacyclo- tetradecane having different substituents: How spin multiplicity influences bond angle and bond lengths (Ru-O-NO) in releasing of NO

Generation of nitric oxide has been a great interest in cell biology as it involves a wide range of physiological functions including the blood pressure control; thus the exploitation of ruthenium chemistry has been motivated in biochemical and clinical points of view. Herein, the structural and electronic properties of ruthenium(II) complexes of 1,4,8,11-tetraazacyclotetradecane containing pyridyl, imidazole and benzimidazole (L1, L2, L3) were analyzed theoretically in the context of how spin multiplicity plays a crucial role influencing the NO release from the LRu-ONO moiety. The results show that β-cleavage of nitrito in the complex motivates the release of NO as it depends highly on total spin multiplicity of metal ion altering significantly the geometrical parameters; particularly, a decrease of bond length of Ru-ONO is highly associated with an increase of RuO-NO bond distance that correlates with the decrease of the Ru-O-NO bond angle ultimately leading to the release of NO; apparently, the bending nature of Ru-O-NO defines its release from the complex. This is consistent with orbital energy (dx2-y2) where the stabilization of axial Ru-O bond in the complex was observed, and proved by molecular orbital studies. In the excitation of the complex (singlet to triplet or singlet to quintet), the NO release has been facilitated, agreeing with the Gibbs free energy data where a lower energy for NO release was obtained compared to other types of excitations. In the calculated electronic spectra, a visible broad band with relatively high intensity for [RuL1ONO]+ was observed, agreeing approximately with reported experimental results.

Chemistry of ruthenium as an electrode for metal–insulator–metal capacitor application

Notwithstanding its excellent properties such as high work function and low resistance, Ru has not been widely applied in the preparation of electrodes for various electronic devices. This is because of the occurrence of severe morphological degradation in the actual devices employing Ru. Herein, we investigated Ru chemistry for electrode application and the degradation mechanism of Ru during subsequent processes such as thin film deposition or thermal annealing. We revealed that subsurface oxygen induces Ru degradation owing to the alteration of Ru chemistry by the pretreatment under various gas ambient conditions and due to the growth behavior of TiO2 deposited via atomic layer deposition (ALD). The degradation of Ru is successfully ameliorated by conducting an appropriate pretreatment prior to ALD. The TiO2 thin film deposited on the pretreated Ru electrode exhibited a rutile-phased crystal structure and smooth surface morphology, thereby resulting in excellent electrical properties. This paper presents an important development in the application of Ru as the electrode that can facilitate the development of various next-generation electronic devices.

Aqueous chemistry of ruthenium(II) complexes containing dimethylsulfoxide, and a chelated disulfoxide ligand or a cyclotetrathia ligand

The aqueous chemistry, including some kinetic studies, of our recently reported [RuII/IIICl(BPSP)]2(μ-Cl)3 (complex 1), where BPSP = 1,2-bis(propylsulfinyl)ethane, and a new complex cis-RuCl2(DMSO)(DMSO)(BESE) (2), where BESE = 1,2-bis(ethylsulfinyl)ethane, is described; both 1 and 2 are fully characterized. Such data are of importance for in vitro studies on cytotoxicity, accumulation and DNA-binding properties in selected cells, findings that will be published elsewhere. Discussed also are the complexes [Ru(12-ane-S4)(DMSO)(H2O)][OTf]2 (3), where 12-ane-S4 = 1,4,7,10-tetrathiacyclododecane, and cis-RuCl2(DMSO)L (4), where L = 3,6,9,14 tetrathiabicyclo-[9.2.1]-tetradeca-11,13-diene. Complexes 3 and 4 were first made by our group, but have been synthesized and studied subsequently by other groups; differences in findings are discussed.

SYNTHESIS AND CHARACTERIZATION OF A NEW RUTHENIUM (II) DIARSINIC AQUACOMPLEX

Ruthenium complexes are used as catalysts, energy converters, some have biological activity, among other applications. The ruthenium chemistry reserves remarkable stability when complexed with organic ligands, mainly bipyridine and tripyridine. Ruthenium polypyridine aquacomplexes have acted as excellent electrocatalysts in the conversion of organic substances, since they offer interesting patterns of binding with ruthenium. The preparation of ruthenium aquacomplexes combining tripyridine and bidentate arsine ligands is not officially described. Good advantages have been found when using ligands containing mixed mono, di or tripyridines with bidentate ligands in their coordination sphere, such as the verified stability of these complexes, without loss of ligands during the process and the possibility of better stereochemical control during the synthesis of these complexes. This work stands out the synthesis, in three stages, of a new ruthenium tripyridine complex containing a bidentate arsine: [Ru(L)(totpy)(OH2)](ClO4)2 (L=Ph2AsCH2CH2AsPh2); (totpy=4'-(4-tolyl)-2,2':6',2''-terpyridine). Each step of the synthetic route showed a significant reaction yield and the voltammetric, spectroscopic and microanalytical characterization results point positively to the proposed chemical structure of the complex.

Expanding the Rich Crystal Chemistry of Ruthenium(V) Oxides via the Discovery of BaRu2O6, Ba5Ru4O15, Ba2Ru3O10, and Sr2Ru3O9(OH) by pH-Controlled Hydrothermal Synthesis

Along the years, ruthenium oxides have been deeply investigated for their magnetic or catalytic properties. The exploration of new synthesis processes, and especially low-temperature ones, is of primary importance to obtain new materials with interesting properties. Here, we highlight the tunability of a low-temperature (200 °C) hydrothermal synthesis route of alkaline-earth ruthenates. Changing only simple physicochemical parameters such as pH, it is possible to obtain a large diversity of metastable compounds. Among them, four compounds, namely, BaRu2O6, Ba2Ru3O10, Ba5Ru4O15, and Sr2Ru3O9(OH) are reported here for the first time. The influence of the reaction parameters (temperature, counter ions, reactant ratio, and pH) is studied. According to these observations, the importance of the reaction pH is highlighted and a reaction scenario is proposed. Finally, the crystal structures of Ba2Ru3O10, Ba5Ru4O15, and Sr2Ru3O9(OH) are reported. These findings further highlight the richness of low-temperature chemistry in the discovery of new metastable phases to be further explored by scientists

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.

Design of Ru-arene Complexes for Antitumor Drugs.

Recently, a number of promising ruthenium complexes have been investigated as anticancer drugs. Ru-arene complexes with [(η6-arene)Ru(X)(Y)(Z)] type, which exhibit a great structural variety, offer much potential in drug design. In this review we provide an overview of the progress in the field of arene ruthenium chemistry. We focus our attention particularly on the molecular structures and the anticancer applications of the Ru-arene complexes. Recent developments in the chemistry of arene ruthenium complexes will provide information for the investigation of novel anticancer organometallic drugs.

Chemistry of ruthenium σ-borane complex, [Cp∗RuCO(μ-H)BH2L] (Cp∗ = η5-C5Me5; L = C7H4NS2) with terminal and internal alkynes: Structural characterization of vinyl hydroborate and vinyl complexes of ruthenium

The chemistry of ruthenium–borane complex, [Cp∗RuCO(μ-H)BH2L] (Cp∗=η5-C5Me5; L=C7H4NS2), 1 with various alkynes has been explored. Photolysis of 1 with alkynyl-Grignard, [HCCMgBr] in toluene led to the isolation of vinyl hydroborate complex [Cp∗Ru(μ-H)BH{HCCH2}L], 2a as a sole product. Compound 2a can be viewed as a ruthenium–borate complex with an ethylene moiety. Further, the chemistry of 1 with various internal and terminal alkynes has been performed in photolytic conditions. Photolysis of 1 with [RCCR] (R=CO2Me) yielded vinyl hydroborate complex [Cp∗Ru(μ-H)BCl{RCCR}L], 2b. Terminal alkynes [HCCR] (R=Ph or CO2Me) under the same reaction conditions led to the isolation of metal vinyl complexes [Cp∗Ru(CO)(C2HR)(L)], 3a and 3b (3a: R=Ph; 3b: R=CO2Me). In addition, DFT calculations were carried out to analyze the bonding and electronic structures of these new compounds.