The field of medicinal inorganic chemistry is rapidly advancing. In particular organometallic complexes have much potential as therapeutic and diagnostic agents. The carbon-bound and other ligands ...allow the thermodynamic and kinetic reactivity of the metal ion to be controlled and also provide a scaffold for functionalization. The establishment of structure-activity relationships and elucidation of the speciation of complexes under conditions relevant to drug testing and formulation are crucial for the further development of promising medicinal applications of organometallic complexes. Specific examples involving the design of ruthenium and osmium arene complexes as anticancer agents are discussed.
We present herein the synthesis of three new bis(corrolato‐ruthenium(III)) complexes containing unsupported Ru–Ru bonds and their characterization in different redox states. The 1H NMR spectra of the ...bis(corrolato‐ruthenium(III)) complexes displayed “normal” chemical shifts and the compounds proved to be EPR‐silent. Crystallographic characterization of the dimers indicated Ru–Ru distances of 2.175 Å, consistent with a triple bond between the two ruthenium centers. All of the synthesized complexes undergo two successive reversible oxidations and a single reversible reduction. A combination of UV/Vis/NIR/EPR spectroelectrochemical studies and DFT calculations established the redox state distributions in these ruthenium–ruthenium‐bonded dimers. Whereas reduction of the dimers is metal‐based and leads to metal‐metal‐bonded mixed‐valent RuII–RuIII species, one‐electron oxidation largely retains the RuIII–RuIII situation with the generation of metal‐bound corrolato radicals. The present study thus concerns the first UV/Vis/NIR/EPR spectroelectrochemical characterization and DFT calculations of ruthenium–ruthenium‐bonded rotationally ordered corrole dimers. The mean plane separation between the two corrole units in these dimers is around 3.543 Å, which is in close agreement to that in the “special pair” in chlorophyll. Oxidation of these ruthenium–ruthenium‐bonded dimers gives rise to two new electronic absorption bands in the NIR region (similar to those of the special pair), which have apparently not been mentioned/observed in earlier reports on ruthenium–ruthenium‐bonded corrole dimers. These bands mainly originate from inter‐corrole transitions.
Mimicking the special pair: A series of ruthenium–ruthenium‐bonded dimeric corrole complexes has been prepared (see figure). Upon one‐electron‐oxidation of these complexes, the RuIII–RuIII situation is largely retained, and metal‐bound corrolato radicals are generated. Two NIR bands at 1064 nm (LMCT‐type) and 2315 nm (ILCT‐type) are seen for a representative oxidized complex, which closely resemble those originating from the radical cations of the photosynthetic “special pair”.
Catalytic depolymerization of polyolefins is a promising chemical recycling strategy to create value-added products from waste plastics, which are accumulating in landfills and the natural ...environment at unsustainable rates. The cleavage of strong C–C bonds in polyolefins can be performed using a noble metal and hydrogen via a hydrogenolysis mechanism. Previously, we identified ruthenium nanoparticles supported on carbon (Ru/C) as a highly active heterogeneous catalyst for the conversion of polyethylene into liquid and gaseous n-alkanes under mild conditions. In the present study, we investigated the catalytic depolymerization of polypropylene (PP) under mild conditions (200–250 °C, 20–50 bar H2). We demonstrate that Ru/C produces C5–C32 iso-alkane yields above 68% in the absence of solvent and identify trade-offs between product yield and temperature, hydrogen pressure, and reaction time. We apply a rigorous analytical method to quantify all liquid and gaseous alkane products. The characterized catalyst was found to be recyclable after the complete depolymerization of high molecular weight PP (M w ∼ 340,000 Da) to liquid and gaseous hydrocarbons and after depolymerization of a postconsumer PP centrifuge tube. Further, the catalyst was shown to be effective in depolymerizing a mixture of high-density polyethylene and PP to produce a mixture of linear and branched liquid alkanes, demonstrating feasibility for the depolymerization of streams of mixed polyolefin waste.
Ruthenium-based complexes have a wide range of targets and mechanisms for anticancer activities. For the treatment of malignant malignancy, ruthenium-based drugs have special features. We establish ...the use of ruthenium-based complexes in the treatment of cancers throughout this review paper. The most common cause of cancer death is metastases, which alternate with primary tumors. Chemotherapy is generally ineffective against all solid human tumors and metastases. The ruthenium based complexes include metal-based complexes like NAMI-A and KP1019, as well as organometallic complexes like RM175, RAPTA-T, and RDC11. The ruthenium metal based complexes were discussed in this review study, together with the remaining clinical anticancer medicines, to explore tumor malignancy.
The design and synthesis of high-performance and low-cost electrocatalysts for the hydrogen evolution reaction (HER), a key half-reaction in water electrolysis, are essential. Owing to their modest ...hydrogen adsorption energy, ruthenium (Ru)-based nanomaterials are considered outstanding candidates to replace the expensive platinum (Pt)-based HER electrocatalysts. In this study, we developed an adsorption-pyrolysis method to construct nitrogen (N)-doped graphene aerogel (N-GA)-supported ultrafine Ru nanocrystal (Ru-NC) nanocomposites (Ru-NCs/N-GA). The particle size of the Ru-NCs and the conductivity of the N-GA substrate can be controlled by varying the pyrolysis temperature. Optimal experiments reveal revealed that 10 wt% Ru-NCs/N-GA nanocomposites require overpotentials of only 52 and 36 mV to achieve a current density of 10 mA cm−2 in 1 mol/L HClO4 and 1 mol/L KOH electrolytes for HER, respectively, which is comparable to 20 wt% Pt/C electrocatalyst. Benefiting from the ultrafine size and uniform dispersion of the Ru-NCs, the synergy between Ru and the highly conductive substrate, and the anchoring effect of the N atom, the Ru-NCs/N-GA nanocomposites exhibit excellent activity and durability in the pH-universal HER, thereby opening a new avenue for the production of commercial HER electrocatalysts.
Benefiting from the ultrafine size/uniform dispersion of Ru nanocrystals, the interaction between Ru and N, and the high conductivity of the substrate, N-doped graphene aerogel-supported Ru nanocrystals exhibit excellent activity and durability for the pH-universal hydrogen evolution reaction.
Ruthenium complexes are a new generation of metal antitumor drugs that are currently of great interest in multidisciplinary research. In this review article, we introduce the applications of ...ruthenium complexes in the diagnosis and therapy of tumors. We focus on the actions of ruthenium complexes on DNA, mitochondria, and endoplasmic reticulum of cells, as well as signaling pathways that induce tumor cell apoptosis, autophagy, and inhibition of angiogenesis. Furthermore, we highlight the use of ruthenium complexes as specific tumor cell probes to dynamically monitor the active biological component of the microenvironment and as excellent photosensitizer, catalyst, and bioimaging agents for phototherapies that significantly enhance the diagnosis and therapeutic effect on tumors. Finally, the combinational use of ruthenium complexes with existing clinical antitumor drugs to synergistically treat tumors is discussed.
Iron-Catalyzed C–H Bond Activation Shang, Rui; Ilies, Laurean; Nakamura, Eiichi
Chemical reviews,
07/2017, Letnik:
117, Številka:
13
Journal Article
Recenzirano
Catalytic C–H bond activation, which was an elusive subject of chemical research until the 1990s, has now become a standard synthetic method for the formation of new C–C and C–heteroatom bonds. The ...synthetic potential of C–H activation was first described for ruthenium catalysis and is now widely exploited by the use of various precious metals. Driven by the increasing interest in chemical utilization of ubiquitous metals that are abundant and nontoxic, iron catalysis has become a rapidly growing area of research, and iron-catalyzed C–H activation has been most actively explored in recent years. In this review, we summarize the development of stoichiometric C–H activation, which has a long history, and catalytic C–H functionalization, which emerged about 10 years ago. We focus in this review on reactions that take place via reactive organoiron intermediates, and we excluded those that use iron as a Lewis acid or radical initiator. The contents of this review are categorized by the type of C–H bond cleaved and the type of bond formed thereafter, and it covers the reactions of simple substrates and substrates possessing a directing group that anchors the catalyst to the substrate, providing an overview of iron-mediated and iron-catalyzed C–H activation reported in the literature by October 2016.
As a highly appealing technology for hydrogen generation, water electrolysis including oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode largely ...depends on the availability of efficient electrocatalysts. Accordingly, over the past years, much effort has been made to develop various electrocatalysts with superior performance and reduced cost. Among them, ruthenium (Ru)-based materials for OER and HER are very promising because of their prominent catalytic activity, pH-universal application, the cheapest price among the precious metal family, and so on. Herein, recent advances in this hot research field are comprehensively reviewed. A general description about water splitting is presented to understand the reaction mechanism and proposed scaling relations toward activities, and key stability issues for Ru-based materials are further given. Subsequently, various Ru-involving electrocatalysts are introduced and classified into different groups for improving or optimizing electrocatalytic properties, with a special focus on several significant bifunctional electrocatalysts along with a simulated water electrolyzer. Finally, a perspective on the existing challenges and future progress of Ru-based catalysts toward OER and HER is provided. The main aim here is to shed some light on the design and construction of emerging catalysts for energy storage and conversion technologies.
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