Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals. Russian-born scientist of Baltic-German ancestry Karl Ernst Claus discovered the element in 1844 at Kazan State University and named it after the Latin name of his homeland, Ruthenia. Ruthenium is usually found as a minor component of platinum ores; the annual production has risen from about 19 tonnes in 2009  to some 35.5 tonnes in 2017. Most ruthenium produced is used in wear-resistant electrical contacts and thick-film resistors. A minor application for ruthenium is in platinum alloys and as a chemistry catalyst. A new application of ruthenium is as the capping layer for extreme ultraviolet photomasks. Ruthenium is generally found in ores with the other platinum group metals in the Ural Mountains and in North and South America. Small but commercially important quantities are also found in pentlandite extracted from Sudbury, Ontario and in pyroxenite deposits in South Africa.
|Appearance||silvery white metallic|
|Standard atomic weight Ar, std(Ru)||101.07(2)|
|Ruthenium in the periodic table|
|Atomic number (Z)||44|
|Element category||transition metal|
|Electron configuration||[Kr] 4d7 5s1|
Electrons per shell
|2, 8, 18, 15, 1|
|Phase at STP||solid|
|Melting point||2607 K (2334 °C, 4233 °F)|
|Boiling point||4423 K (4150 °C, 7502 °F)|
|Density (near r.t.)||12.45 g/cm3|
|when liquid (at m.p.)||10.65 g/cm3|
|Heat of fusion||38.59 kJ/mol|
|Heat of vaporization||619 kJ/mol|
|Molar heat capacity||24.06 J/(mol·K)|
|Oxidation states||−4, −2, +1, +2, +3, +4, +5, +6, +7, +8 (a mildly acidic oxide)|
|Electronegativity||Pauling scale: 2.2|
|Atomic radius||empirical: 134 pm|
|Covalent radius||146±7 pm|
Spectral lines of ruthenium
|Crystal structure|| hexagonal close-packed (hcp)|
|Speed of sound thin rod||5970 m/s (at 20 °C)|
|Thermal expansion||6.4 µm/(m·K) (at 25 °C)|
|Thermal conductivity||117 W/(m·K)|
|Electrical resistivity||71 nΩ·m (at 0 °C)|
|Magnetic susceptibility||+43.2·10−6 cm3/mol (298 K)|
|Young's modulus||447 GPa|
|Shear modulus||173 GPa|
|Bulk modulus||220 GPa|
|Brinell hardness||2160 MPa|
|Naming||after Ruthenia (Latin for: medieval Kyivska Rus' region)|
|Discovery and first isolation||Karl Ernst Claus (1844)|
|Main isotopes of ruthenium|
|Z||Element||No. of electrons/shell|
|26||iron||2, 8, 14, 2|
|44||ruthenium||2, 8, 18, 15, 1|
|76||osmium||2, 8, 18, 32, 14, 2|
|108||hassium||2, 8, 18, 32, 32, 14, 2|
Whereas all other group 8 elements have 2 electrons in the outermost shell, in ruthenium, the outermost shell has only one electron (the final electron is in a lower shell). This anomaly is observed in the neighboring metals niobium (41), molybdenum (42), and rhodium (45).
Ruthenium has four crystal modifications and does not tarnish unless subject to high temperatures. Ruthenium dissolves in fused alkalis to give ruthenates (RuO2−
4), is not attacked by acids (even aqua regia) but is attacked by halogens at high temperatures. Indeed, ruthenium is most readily attacked by oxidizing agents. Small amounts of ruthenium can increase the hardness of platinum and palladium. The corrosion resistance of titanium is increased markedly by the addition of a small amount of ruthenium. The metal can be plated by electroplating and by thermal decomposition. A ruthenium-molybdenum alloy is known to be superconductive at temperatures below 10.6 K. Ruthenium is the last of the 4d transition metals that can assume the group oxidation state +8, and even then it is less stable there than the heavier congener osmium: this is the first group from the left of the table where the second and third-row transition metals display notable differences in chemical behavior. Like iron but unlike osmium, ruthenium can form aqueous cations in its lower oxidation states of +2 and +3.
Ruthenium is the first in a downward trend in the melting and boiling points and atomization enthalpy in the 4d transition metals after the maximum seen at molybdenum, because the 4d subshell is more than half full and the electrons are contributing less to metallic bonding. (Technetium, the previous element, has an exceptionally low value that is off the trend due to its half-filled [Kr]4d55s2 configuration, though the small amount of energy needed to excite it to a [Kr]4d65s1 configuration indicates that it is not as far off the trend in the 4d series as manganese in the 3d transition series.) Unlike the lighter congener iron, ruthenium is paramagnetic at room temperature, as iron also is above its Curie point.
The reduction potentials in acidic aqueous solution for some common ruthenium ions are shown below:
|0.455 V||Ru2+ + 2e−||↔ Ru|
|0.249 V||Ru3+ + e−||↔ Ru2+|
|1.120 V||RuO2 + 4H+ + 2e−||↔ Ru2+ + 2H2O|
4 + 8H+ + 4e−
|↔ Ru2+ + 4H2O|
4 + 8H+ + 5e−
|↔ Ru2+ + 4H2O|
|1.387 V||RuO4 + 4H+ + 4e−||↔ RuO2 + 2H2O|
Naturally occurring ruthenium is composed of seven stable isotopes. Additionally, 34 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are 106Ru with a half-life of 373.59 days, 103Ru with a half-life of 39.26 days and 97Ru with a half-life of 2.9 days.
Fifteen other radioisotopes have been characterized with atomic weights ranging from 89.93 u (90Ru) to 114.928 u (115Ru). Most of these have half-lives that are less than five minutes except 95Ru (half-life: 1.643 hours) and 105Ru (half-life: 4.44 hours).
The primary decay mode before the most abundant isotope, 102Ru, is electron capture and the primary mode after is beta emission. The primary decay product before 102Ru is technetium and the primary decay product after is rhodium.
As the 74th most abundant element in Earth's crust, ruthenium is relatively rare, found in about 100 parts per trillion. This element is generally found in ores with the other platinum group metals in the Ural Mountains and in North and South America. Small but commercially important quantities are also found in pentlandite extracted from Sudbury, Ontario, Canada, and in pyroxenite deposits in South Africa. The native form of ruthenium is a very rare mineral (Ir replaces part of Ru in its structure).
Roughly 12 tonnes of ruthenium are mined each year with world reserves estimated at 5,000 tonnes. The composition of the mined platinum group metal (PGM) mixtures varies widely, depending on the geochemical formation. For example, the PGMs mined in South Africa contain on average 11% ruthenium while the PGMs mined in the former USSR contain only 2% (1992). Ruthenium, osmium, and iridium are considered the minor platinum group metals.
Ruthenium, like the other platinum group metals, is obtained commercially as a by-product from nickel, and copper, and platinum metals ore processing. During electrorefining of copper and nickel, noble metals such as silver, gold, and the platinum group metals precipitate as anode mud, the feedstock for the extraction. The metals are converted to ionized solutes by any of several methods, depending on the composition of the feedstock. One representative method is fusion with sodium peroxide followed by dissolution in aqua regia, and solution in a mixture of chlorine with hydrochloric acid. Osmium, ruthenium, rhodium, and iridium are insoluble in aqua regia and readily precipitate, leaving the other metals in solution. Rhodium is separated from the residue by treatment with molten sodium bisulfate. The insoluble residue, containing Ru, Os, and Ir is treated with sodium oxide, in which Ir is insoluble, producing dissolved Ru and Os salts. After oxidation to the volatile oxides, RuO
4 is separated from OsO
4 by precipitation of (NH4)3RuCl6 with ammonium chloride or by distillation or extraction with organic solvents of the volatile osmium tetroxide. Hydrogen is used to reduce ammonium ruthenium chloride yielding a powder. The product is reduced using hydrogen, yielding the metal as a powder or sponge metal that can be treated with powder metallurgy techniques or argon-arc welding.
The oxidation states of ruthenium range from 0 to +8, and −2. The properties of ruthenium and osmium compounds are often similar. The +2, +3, and +4 states are the most common. The most prevalent precursor is ruthenium trichloride, a red solid that is poorly defined chemically but versatile synthetically.
Ruthenium can be oxidized to ruthenium(IV) oxide (RuO2, oxidation state +4) which can in turn be oxidized by sodium metaperiodate to the volatile yellow tetrahedral ruthenium tetroxide, RuO4, an aggressive, strong oxidizing agent with structure and properties analogous to osmium tetroxide. Like osmium tetroxide, ruthenium tetroxide is a potent fixative and stain for electron microscopy of organic materials, and is mostly used to reveal the structure of polymer samples. Dipotassium ruthenate (K2RuO4, +6), and potassium perruthenate (KRuO4, +7) are also known. Unlike osmium tetroxide, ruthenium tetroxide is less stable and is strong enough as an oxidising agent to oxidise dilute hydrochloric acid and organic solvents like ethanol at room temperature, and is easily reduced to ruthenate (RuO2−
4) in aqueous alkaline solutions; it decomposes to form the dioxide above 100 °C. Unlike iron but like osmium, ruthenium does not form oxides in its lower +2 and +3 oxidation states. Ruthenium forms dichalcogenides only when reacted directly with the chalcogens, which are diamagnetic semiconductors crystallizing in the pyrite structure and thus must contain ruthenium(II).
Like iron, ruthenium does not readily form oxoanions, and prefers to achieve high coordination numbers with hydroxide ions instead. Ruthenium tetroxide is reduced by cold dilute potassium hydroxide to form black potassium perruthenate, KRuO4, with ruthenium in the +7 oxidation state. Potassium perruthenate can also be produced by oxidising potassium ruthenate, K2RuO4, with chlorine gas. The perruthenate ion is unstable and is reduced by water to form the orange ruthenate. Potassium ruthenate may be synthesized by reacting ruthenium metal with potassium hydroxide and potassium nitrate.
Some mixed oxides are also known, such as MIIRuIVO3, Na3RuVO4, Na
7, and MII
The highest known ruthenium halide is the hexafluoride, a dark brown solid that melts at 54 °C. It hydrolyzes violently upon contact with water and easily disproportionates to form a mixture of lower ruthenium fluorides, releasing fluorine gas. Ruthenium pentafluoride is a tetrameric dark green solid that is also readily hydrolyzed, melting at 86.5 °C. The yellow ruthenium tetrafluoride is probably also polymeric and can be formed by reducing the pentafluoride with iodine. Among the binary compounds of ruthenium, these high oxidation states are known only in the oxides and fluorides.
Ruthenium trichloride is a well-known compound, existing in a black α-form and a dark brown β-form: the trihydrate is red. Of the known trihalides, trifluoride is dark brown and decomposes above 650 °C, tetrabromide is dark-brown and decomposes above 400 °C, and triiodide is black. Of the dihalides, difluoride is not known, dichloride is brown, dibromide is black, and diiodide is blue. The only known oxyhalide is the pale green ruthenium(VI) oxyfluoride, RuOF4.
Ruthenium forms a variety of coordination complexes. Examples are the many pentammine derivatives [Ru(NH3)5L]n+ that often exist for both Ru(II) and Ru(III). Derivatives of bipyridine and terpyridine are numerous, best known being the luminescent tris(bipyridine)ruthenium(II) chloride.
Ruthenium forms a wide range compounds with carbon-ruthenium bonds. Grubbs' catalyst is used for alkene metathesis. Ruthenocene is analogous to ferrocene structurally, but exhibits distinctive redox properties. The colorless liquid ruthenium pentacarbonyl converts in the absence of CO pressure to the dark red solid triruthenium dodecacarbonyl. Ruthenium trichloride reacts with carbon monoxide to give many derivatives including RuHCl(CO)(PPh3)3 and Ru(CO)2(PPh3)3 (Roper's complex). Heating solutions of ruthenium trichloride in alcohols with triphenylphosphine gives tris(triphenylphosphine)ruthenium dichloride (RuCl2(PPh3)3), which converts to the hydride complex chlorohydridotris(triphenylphosphine)ruthenium(II) (RuHCl(PPh3)3).
Though naturally occurring platinum alloys containing all six platinum-group metals were used for a long time by pre-Columbian Americans and known as a material to European chemists from the mid-16th century, not until the mid-18th century was platinum identified as a pure element. That natural platinum contained palladium, rhodium, osmium and iridium was discovered in the first decade of the 19th century. Platinum in alluvial sands of Russian rivers gave access to raw material for use in plates and medals and for the minting of ruble coins, starting in 1828. Residues from platinum production for coinage were available in the Russian Empire, and therefore most of the research on them was done in Eastern Europe.
It is possible that the Polish chemist Jędrzej Śniadecki isolated element 44 (which he called "vestium" after the asteroid Vesta discovered shortly before) from South American platinum ores in 1807. He published an announcement of his discovery in 1808. His work was never confirmed, however, and he later withdrew his claim of discovery.
Jöns Berzelius and Gottfried Osann nearly discovered ruthenium in 1827. They examined residues that were left after dissolving crude platinum from the Ural Mountains in aqua regia. Berzelius did not find any unusual metals, but Osann thought he found three new metals, which he called pluranium, ruthenium, and polinium. This discrepancy led to a long-standing controversy between Berzelius and Osann about the composition of the residues. As Osann was not able to repeat his isolation of ruthenium, he eventually relinquished his claims. The name "ruthenium" was chosen by Osann because the analysed samples stemmed from the Ural Mountains in Russia. The name itself derives from Ruthenia, the Latin word for Rus', a historical area that included present-day Ukraine, Belarus, western Russia, and parts of Slovakia and Poland.
In 1844, Karl Ernst Claus, a Russian scientist of Baltic German descent, showed that the compounds prepared by Gottfried Osann contained small amounts of ruthenium, which Claus had discovered the same year. Claus isolated ruthenium from the platinum residues of rouble production while he was working in Kazan University, Kazan, the same way its heavier congener osmium had been discovered four decades earlier. Claus showed that ruthenium oxide contained a new metal and obtained 6 grams of ruthenium from the part of crude platinum that is insoluble in aqua regia. Choosing the name for the new element, Claus stated: "I named the new body, in honour of my Motherland, ruthenium. I had every right to call it by this name because Mr. Osann relinquished his ruthenium and the word does not yet exist in chemistry."
Because it hardens platinum and palladium alloys, ruthenium is used in electrical contacts, where a thin film is sufficient to achieve the desired durability. With similar properties and lower cost than rhodium, electric contacts are a major use of ruthenium. The plate is applied to the base by electroplating or sputtering.
Ruthenium is seldom alloyed with metals outside the platinum group, where small quantities improve some properties. The added corrosion resistance in titanium alloys led to the development of a special alloy with 0.1% ruthenium. Ruthenium is also used in some advanced high-temperature single-crystal superalloys, with applications that include the turbines in jet engines. Several nickel based superalloy compositions are described, such as EPM-102 (with 3% Ru), TMS-162 (with 6% Ru), TMS-138, and TMS-174, the latter two containing 6% rhenium. Fountain pen nibs are frequently tipped with ruthenium alloy. From 1944 onward, the famous Parker 51 fountain pen was fitted with the "RU" nib, a 14K gold nib tipped with 96.2% ruthenium and 3.8% iridium.
Ruthenium is a component of mixed-metal oxide (MMO) anodes used for cathodic protection of underground and submerged structures, and for electrolytic cells for such processes as generating chlorine from salt water. The fluorescence of some ruthenium complexes is quenched by oxygen, finding use in optode sensors for oxygen. Ruthenium red, [(NH3)5Ru-O-Ru(NH3)4-O-Ru(NH3)5]6+, is a biological stain used to stain polyanionic molecules such as pectin and nucleic acids for light microscopy and electron microscopy. The beta-decaying isotope 106 of ruthenium is used in radiotherapy of eye tumors, mainly malignant melanomas of the uvea. Ruthenium-centered complexes are being researched for possible anticancer properties. Compared with platinum complexes, those of ruthenium show greater resistance to hydrolysis and more selective action on tumors.
Many ruthenium-containing compounds exhibit useful catalytic properties. The catalysts are conveniently divided into those that are soluble in the reaction medium, homogeneous catalysts, and those that are not, which are called heterogeneous catalysts.
Ruthenium nanoparticles can be formed inside halloysite. This abundant mineral naturally has a structure of rolled nanosheets (nanotubes), which can support both the Ru nanocluster synthesis and its products for subsequent use in industrial catalysis.
Solutions containing ruthenium trichloride are highly active for olefin metathesis. Such catalysts are used commercially for the production of polynorbornene for example. Well defined ruthenium carbene and alkylidene complexes show comparable reactivity and provide mechanistic insights into the industrial processes. The Grubbs' catalysts for example have been employed in the preparation of drugs and advanced materials.
Ruthenium complexes are highly active catalysts for transfer hydrogenations (sometimes referred to as "borrowing hydrogen" reactions). This process is employed for the enantioselective hydrogenation of ketones, aldehydes, and imines. This reaction exploits using chiral ruthenium complexes introduced by Ryoji Noyori. For example, (cymene)Ru(S,S-TsDPEN) catalyzes the hydrogenation of benzil into (R,R)-hydrobenzoin. In this reaction, formate and water/alcohol serve as the source of H2:
In 2012, Masaaki Kitano and associates, working with an organic ruthenium catalyst, demonstrated ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store. Small-scale, intermittent production of ammonia, for local agricultural use, may be a viable substitute for electrical grid attachment as a sink for power generated by wind turbines in isolated rural installations.
Some ruthenium complexes absorb light throughout the visible spectrum and are being actively researched for solar energy technologies. For example, Ruthenium-based compounds have been used for light absorption in dye-sensitized solar cells, a promising new low-cost solar cell system.
Many ruthenium-based oxides show very unusual properties, such as a quantum critical point behavior, exotic superconductivity (in its strontium ruthenate form), and high-temperature ferromagnetism.
(Cymene)ruthenium dichloride dimer is the organometallic compound with the formula [(cymene)RuCl2]2. This red-coloured, diamagnetic solid is a reagent in organometallic chemistry and homogeneous catalysis. The complex is structurally similar to (benzene)ruthenium dichloride dimer.Dichlorotetrakis(dimethylsulfoxide)ruthenium(II)
Dichlorotetrakis(dimethyl sulfoxide) ruthenium(II) describes coordination compounds with the formula RuCl2(dmso)4, where DMSO is dimethylsulfoxide. Both cis and trans isomers are known, but the cis isomer is more common. The cis isomer (pictured) is a yellow, air-stable solid that is soluble in some organic solvents. These compounds have attracted attention as possible anti-cancer drugs.Dichlorotris(triphenylphosphine)ruthenium(II)
Dichlorotris(triphenylphosphine)ruthenium(II) is a coordination complex of ruthenium. It is a chocolate brown solid that is soluble in organic solvents such as benzene. The compound is used as a precursor to other complexes including those used in homogeneous catalysis.Group 8 element
Group 8 is a group of chemical element in the periodic table. It consists of iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs). They are all transition metals. Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior.
"Group 8" is the modern IUPAC name for this group; the old style name was group VIIIB in the CAS, US system or group VIIIA in the old IUPAC, European system.
Group 8 should not be confused with the old-style group name of VIIIA by CAS/US naming. That group is now called group 18.Isotopes of ruthenium
Naturally occurring ruthenium (44Ru) is composed of seven stable isotopes. Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are 106Ru, with a half-life of 373.59 days; 103Ru, with a half-life of 39.26 days and 97Ru, with a half-life of 2.9 days.
Twenty-four other radioisotopes have been characterized with atomic weights ranging from 86.95 u (87Ru) to 119.95 u (120Ru). Most of these have half-lives that are less than five minutes, excepting 95Ru (half-life: 1.643 hours) and 105Ru (half-life: 4.44 hours).
The primary decay mode before the most abundant isotope, 102Ru, is electron capture and the primary mode after is beta emission. The primary decay product before 102Ru is technetium and the primary product after is rhodium.Lithium ruthenate
Lithium ruthenate, Li2RuO3, is a chemical compound of lithium, ruthenium and oxygen. It has a layered honeycomb crystal structure, and can be prepared by direct calcination of Ru metal and lithium carbonate at ca. 700 °C. It is a potential lithium-ion battery electrode material, though this application is hindered by the high costs of Ru, as compared to the cheaper Li2MnO3 alternative.Natural nuclear fission reactor
A natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions have occurred. This can be examined by analysis of isotope ratios. The existence of this phenomenon was discovered in 1972 at Oklo in Gabon by French physicist Francis Perrin. The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Paul Kazuo Kuroda. The conditions found were very similar to what was predicted.
Oklo is the only known location for this in the world and consists of 16 sites at which self-sustaining nuclear fission reactions are thought to have taken place approximately 1.7 billion years ago, and ran for a few hundred thousand years, averaging probably less than 100 kW of thermal power during that time.Organoruthenium chemistry
Organoruthenium chemistry is the chemistry of organometallic compounds containing a carbon to ruthenium chemical bond. Several organoruthenium catalysts are of commercial interest and organoruthenium compounds have been considered for cancer therapy.
The chemistry has some stoichiometric similarities with organoiron chemistry, as iron is directly above ruthenium in group 8 of the periodic table. The most important reagents for the introduction of ruthenium are ruthenium(III) chloride and triruthenium dodecacarbonyl.
In its organometallic compounds, ruthenium is known to adopt oxidation states from -2 ([Ru(CO)4]2−) to +6 ([RuN(Me)4]−). Most common are those in the 2+ oxidation state, as illustrated below.Platinum group
The platinum-group metals (abbreviated as the PGMs; alternatively, the platinoids, platinides, platidises, platinum group, platinum metals, platinum family or platinum-group elements (PGEs)) are six noble, precious metallic elements clustered together in the periodic table. These elements are all transition metals in the d-block (groups 8, 9, and 10, periods 5, 6 and 7).The six platinum-group metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum. They have similar physical and chemical properties, and tend to occur together in the same mineral deposits. However they can be further subdivided into the iridium-group platinum-group elements (IPGEs: Os, Ir, Ru) and the palladium-group platinum-group elements (PPGEs: Rh, Pt, Pd) based on their behaviour in geological systems.The three elements above the platinum group in the periodic table (iron, nickel and cobalt) are all ferromagnetic, these being the only known transition metals with this property.Precious metal
A precious metal is a rare, naturally occurring metallic chemical element of high economic value.
Chemically, the precious metals tend to be less reactive than most elements (see noble metal). They are usually ductile and have a high lustre. Historically, precious metals were important as currency but are now regarded mainly as investment and industrial commodities. Gold, silver, platinum, and palladium each have an ISO 4217 currency code.
The best known precious metals are the coinage metals, which are gold and silver. Although both have industrial uses, they are better known for their uses in art, jewelry, and coinage. Other precious metals include the platinum group metals: ruthenium, rhodium, palladium, osmium, iridium, and platinum, of which platinum is the most widely traded.
The demand for precious metals is driven not only by their practical use but also by their role as investments and a store of value. Historically, precious metals have commanded much higher prices than common industrial metals.Ruthenium(III) chloride
Ruthenium(III) chloride is the chemical compound with the formula RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3·xH2O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a varying proportion of water of crystallization, often approximating to a trihydrate, is a commonly used starting material in ruthenium chemistry. The compound is also widely regarded as a prime candidate to realize Kitaev quantum spin liquid state with Majorana Fermion excitations.Ruthenium(IV) oxide
Ruthenium(IV) oxide is the inorganic compound with the formula RuO2. This black solid is the most common oxide of ruthenium. It is widely used as an electrocatalyst for producing chlorine, chlorine oxides, and O2 catalyst is ruthenium(IV) oxide. Like many dioxides, RuO2 adopts the rutile structure.Ruthenium boride
Ruthenium borides are compounds of ruthenium and boron. Their most remarkable property is potentially high hardness. Vickers hardness HV = 50 GPa was reported for thin films composed of RuB2 and Ru2B3 phases. This value is significantly higher than those of bulk RuB2 or Ru2B3, but it has to be confirmed independently, as measurements on superhard materials are intrinsically difficult. For example, note that the initial report on extreme hardness of related material rhenium diboride was probably too optimistic.Ruthenium hexafluoride
Ruthenium hexafluoride, also ruthenium(VI) fluoride (RuF6), is a compound of ruthenium and fluorine and one of the seventeen known binary hexafluorides.Ruthenium red
The inorganic dye ammoniated ruthenium oxychloride, also known as ruthenium red, is used in histology to stain aldehyde fixed mucopolysaccharides.
Ruthenium red (RR) has also been used as a pharmacological tool to study specific cellular mechanisms. Selectivity is a significant issue in such studies as RR is known to interact with a large number of proteins. These include mammalian ion channels (CatSper1, TASK, RyR1, RyR2, RyR3, TRPM6, TRPM8, TRPV1, TRPV2, TRPV3, TRPV4, TRPV5, TRPV6, TRPA1, mCa1, mCa2, CALHM1) TRPP3, a plant ion channel, Ca2+-ATPase, mitochondrial Ca2+ uniporter, tubulin, myosin light-chain phosphatase, and Ca2+ binding proteins such as calmodulin. Ruthenium red displays nanomolar potency against several of its binding partners (e.g. TRPV4, ryanodine receptors,...). For example, it is a potent inhibitor of intracellular calcium release by ryanodine receptors (Kd ~20 nM). As a TRPA1 blocker, it assists in reducing the airway inflammation caused by pepper spray.
RR has been used on plant material since 1890 for staining pectins, mucilages, and gums. RR is a stereoselective stain for pectic acid, insofar as the staining site occurs between each monomer unit and the next adjacent neighbor.Ruthenium tetroxide
Ruthenium tetroxide (Ruthenium(VIII) oxide) is the inorganic compound with the formula RuO4. It is a colourless, diamagnetic liquid, but samples are typically black due to impurities. It is volatile. The analogous OsO4 is more widely used and better known. One of the few solvents in which it forms stable solutions is CCl4.Ruthenocene
Ruthenocene is an organoruthenium compound with the formula (C5H5)2Ru. This pale yellow, volatile solid is classified as a sandwich compound and more specifically, as a metallocene.Tetrasodium tris(bathophenanthroline disulfonate)ruthenium(II)
Tetrasodium tris(bathophenanthroline disulfonate)ruthenium(II) (Na4Ru(bps)3) is a coordination compound containing a ruthenium center. In this form, it is the salt of a sulfonic acid. This compound is an extension of the well known phenanthroline series of coordination compounds. Ruthenium(II) tris(bathophenanthroline disulfonate), referring to the anionic fragment, is used as a protein dye in biochemistry for differentiating and detecting different proteins in laboratory settings.
In recent years, 2-D electrophoresis has been widely accepted as a standard procedure to separate complex protein mixtures in proteome studies (Proteomics). Protein visualisation by Ruthenium(II) tris(bathophenthroline disulfonate) has become a firmly established and widely used method in proteomic analysis and a crucial step in gene expression profiling.
For protein detection, it is advantageous to use fluorescent labels containing chromophores which have longer excitation wavelength and emission wavelength than the aromatic amino acids. The dyes used for this important step should combine attributes like good signal to background ratio (contrast), broad linear dynamic range, broad application range, photochemical stability and compatibility to protein identification techniques, e.g. mass spectrometry (MS) or Western blotting.
Originally, the ruthenium transition metal complex, ruthenium(II) tris(4,7-diphenyl-1,10-phenanthroline disulfonate) also termed as ruthenium(II) tris(bathophentroline disulfonate) (RuBPS) was synthesized by Bannwarth as a precursor molecule for a dye that was used as a non-radioactive label for oligo nucleotides. Later, Rabilloud et al. used RuBPS as a fluorescent label for protein detection in polyacrylamide gels. The fact that RuBPS is not only easy to synthesize but also easy to handle, induced further developments in this field.
Lamanda et al. improved the RuBPS staining protocol by selectively destaining the polyacrylamide matrix while the protein content remained tinctured. This new technique entailed a variety of advantages like strong signals, ameliorated signal to background ratio, better linearity and advanced baseline resolution.Tris(bipyridine)ruthenium(II) chloride
Tris(bipyridine)ruthenium(II) chloride is the chloride salt coordination complex with the formula [Ru(bpy)3]2+. This red crystalline salt is obtained as the hexahydrate, although all of the properties of interest are in the cation [Ru(bpy)3]2+, which has received much attention because of its distinctive optical properties. The chlorides can be replaced with other anions, such as PF6−.