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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. Structure and bonding Ruthenocene consists of a ruthenium ion sandwiched in between two cyclopentadienyl rings. It features ruthenium centre bound symmetrically to the planes of two cyclopentadienyl rings. It is closely related to the isoelectronic ferrocene. In contrast to ferrocene, wherein the cyclopentadienyl rings are in a staggered conformation, those of ruthenocene crystallise with an eclipsed conformation. This difference is due to the larger ionic radius of ruthenium, which increases the distance between the cyclopentadienyl rings, decreasing steric interactions and allowing an eclipsed conformation to prevail. In solution, these rings rotate with a very low barrier. Preparation Ruthenocene was first synthesized in 1952 by Geoffrey Wilkinson, a Nobel laureate who had collaborated in assi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmocene
Osmocene is an organoosmium compound found as a white solid. It is a metallocene with the formula Os(C5H5)2. Synthesis Osmocene is commercially available. It may be prepared by the reaction of osmium tetroxide with hydrobromic acid followed by zinc and cyclopentadiene. It was first synthesized by Ernst Otto Fischer and Heinrich Grumbert via the reaction of osmium(IV) chloride with excess sodium cyclopentadienide in dimethoxyethane, where osmium(II) chloride is presumed to be an intermediate formed ''in situ''. Alternatively, cyclopentadienyl magnesium bromide could be reacted with osmium(IV) chloride, though this has worse yields. Properties Osmocene is a white solid. The molecular structure features an osmium ion sandwiched between two cyclopentadienyl rings. It is isomorphous to the lighter homologue ruthenocene, both crystallizing in an eclipsed conformation. This is in contrast to ferrocene, which crystallizes with its rings staggered. Compared to ferrocene and ruthen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrocene
Ferrocene is an organometallic compound with the formula . The molecule is a complex consisting of two cyclopentadienyl rings bound to a central iron atom. It is an orange solid with a camphor-like odor, that sublimes above room temperature, and is soluble in most organic solvents. It is remarkable for its stability: it is unaffected by air, water, strong bases, and can be heated to 400 °C without decomposition. In oxidizing conditions it can reversibly react with strong acids to form the ferrocenium cation . The rapid growth of organometallic chemistry is often attributed to the excitement arising from the discovery of ferrocene and its many analogues, such as metallocenes. History Discovery Ferrocene was discovered by accident thrice. The first known synthesis may have been made in the late 1940s by unknown researchers at Union Carbide, who tried to pass hot cyclopentadiene vapor through an iron pipe. The vapor reacted with the pipe wall, creating a "yellow slu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoruthenium Compounds
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 ( u(CO)4sup>2−) to +6 ( uN(Me)4sup>−). Most common are those in the 2+ oxidation state, as illustrated below. File:Grubbs Catalyst 1st Generation.svg, 1st generation Grubbs catalyst File:ShvoCat.png, Shvo catalyst File:RuCymCl2.png, (cymene)ruthenium dichloride dimer File:Trirutheniumdodecacarbonyl.svg, triruthenium dodecacarbonyl. File:Chloro(cyclopentadienyl)bis(triphenylp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallocenes
A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metal center (M) in the oxidation state II, with the resulting general formula Closely related to the metallocenes are the metallocene derivatives, e.g. titanocene dichloride, vanadocene dichloride. Certain metallocenes and their derivatives exhibit catalytic properties, although metallocenes are rarely used industrially. Cationic group 4 metallocene derivatives related to p2ZrCH3sup>+ catalyze olefin polymerization. Some metallocenes consist of metal plus two cyclooctatetraenide anions (, abbreviated cot2−), namely the lanthanocenes and the actinocenes (uranocene and others). Metallocenes are a subset of a broader class of compounds called sandwich compounds. In the structure shown at right, the two pentagons are the cyclopentadienyl anions with circles inside them indicating they are aromatically stabilized. Here they are shown in a staggered conformation. His ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoruthenium Compound
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 ( u(CO)4sup>2−) to +6 ( uN(Me)4sup>−). Most common are those in the 2+ oxidation state, as illustrated below. File:Grubbs Catalyst 1st Generation.svg, 1st generation Grubbs catalyst File:ShvoCat.png, Shvo catalyst File:RuCymCl2.png, (cymene)ruthenium dichloride dimer File:Trirutheniumdodecacarbonyl.svg, triruthenium dodecacarbonyl. File:Chloro(cyclopentadienyl)bis(tripheny ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallocene
A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metal center (M) in the oxidation state II, with the resulting general formula Closely related to the metallocenes are the metallocene derivatives, e.g. titanocene dichloride, vanadocene dichloride. Certain metallocenes and their derivatives exhibit catalytic properties, although metallocenes are rarely used industrially. Cationic group 4 metallocene derivatives related to p2ZrCH3sup>+ catalyze olefin polymerization. Some metallocenes consist of metal plus two cyclooctatetraenide anions (, abbreviated cot2−), namely the lanthanocenes and the actinocenes ( uranocene and others). Metallocenes are a subset of a broader class of compounds called sandwich compounds. In the structure shown at right, the two pentagons are the cyclopentadienyl anions with circles inside them indicating they are aromatically stabilized. Here they are shown in a staggered conformation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruthenium Trisacetylacetonate
Ruthenium(III) acetylacetonate is a coordination complex with the formula Ru(O2C5H7)3. O2C5H7− is the ligand called acetylacetonate. This compound exists as a dark violet solid that is soluble in most organic solvents. It is used as a precursor to other compounds of ruthenium. Preparation In 1914 tris(acetylacetonato)ruthenium (III) was first prepared by the reaction of ruthenium(III) chloride and acetylacetone in the presence of potassium bicarbonate. Since then, alternative synthetic routes have been examined, but the original procedure remains useful with minor variations: :RuCl3•3H2O + MeCOCH2COMe → Ru(acac)3 + 3 HCl + 3 H2O Structure and properties This compound has idealized D3 symmetry. Six oxygen atoms surround the central ruthenium atom in an octahedral arrangement. The average Ru-O bond length in Ru(acac)3 is 2.00 Å. Because Ru(acac)3 is low spin, there is one unpaired ''d'' electron, causing this compound to be paramagnetic. Ru(acac)3 has a magnetic susceptibili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weakly Coordinating Anion
Anions that interact weakly with cations are termed non-coordinating anions, although a more accurate term is weakly coordinating anion. Non-coordinating anions are useful in studying the reactivity of electrophilic cations. They are commonly found as counterions for cationic metal complexes with an unsaturated coordination sphere. These special anions are essential components of homogeneous alkene polymerisation catalysts, where the active catalyst is a coordinatively unsaturated, cationic transition metal complex. For example, they are employed as counterions for the 14 valence electron cations C5H5)2ZrRsup>+ (R = methyl or a growing polyethylene chain). Complexes derived from non-coordinating anions have been used to catalyze hydrogenation, hydrosilylation, oligomerization, and the living polymerization of alkenes. The popularization of non-coordinating anions has contributed to increased understanding of agostic complexes wherein hydrocarbons and hydrogen serve as ligands. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruthenium Trichloride
Ruthenium(III) chloride is the chemical compound with the formula RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3·''x''H2O. 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. Preparation and properties Anhydrous ruthenium(III) chloride is usually prepared by heating powdered ruthenium metal with chlorine. In the original synthesis, the chlorination was conducted in the presence of carbon monoxide, the product being carried by the gas stream and crystallising upon cooling. Two allotropes of RuCl3 are known. The black α-form adopts the CrCl3-type structure with long Ru-Ru contacts of 346 pm. This allotrope has honeycomb layers of Ru3+ which are surrounded with an octahedral cage of Cl− anions. The ruthenium cations are magnetic residing in a low-spin J~1/2 ground st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Cyclopentadienide
Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are pink owing to traces of oxidized impurities. Preparation Sodium cyclopentadienide is commercially available as a solution in THF. It is prepared by treating cyclopentadiene with sodium: : The conversion can be conducted by heating a suspension of molten sodium in dicyclopentadiene.Tarun K. Panda, Michael T. Gamer, Peter W. Roesky "An Improved Synthesis of Sodium and Potassium Cyclopentadienide" Organometallics, 2003, 22, 877–878. In former times, the sodium was provided in the form of "sodium wire" or "sodium sand", a fine dispersion of sodium prepared by melting sodium in refluxing xylene and rapidly stirring. Sodium hydride is a convenient base: : In early work, Grignard reagents were used as bases. With a p''K''a of 15, cyclop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobaltocene
Cobaltocene, known also as bis(cyclopentadienyl)cobalt(II) or even "bis Cp cobalt", is an organocobalt compound with the formula Co(C5H5)2. It is a dark purple solid that sublimes readily slightly above room temperature. Cobaltocene was discovered shortly after ferrocene, the first metallocene. Due to the ease with which it reacts with oxygen, the compound must be handled and stored using air-free techniques. Synthesis Cobaltocene is prepared by the reaction of sodium cyclopentadienide (NaC5H5) with anhydrous cobalt(II) chloride in THF solution. Sodium chloride is cogenerated, and the organometallic product is usually purified by vacuum sublimation. Structure and bonding In Co(C5H5)2 the Co centre is "sandwiched" between two cyclopentadienyl (Cp) rings. The Co–C bond lengths are about 2.1 Å, slightly longer than the Fe–C bond in ferrocene. Co(C5H5)2 belongs to a group of organometallic compounds called metallocenes or sandwich compounds. Cobaltocene has 19 valence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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