Cobaltocenium

picture info	Cobaltocenium 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 Cyclopentadiene, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Rhodocene Rhodocene is a chemical compound with the formula . Each molecule contains an atom of rhodium bound between two planar aromaticity, aromatic systems of five carbon atoms known as cyclopentadienyl rings in a sandwich compound, sandwich arrangement. It is an Organometallic chemistry, organometallic compound as it has (hapticity, haptic) covalent bond, covalent rhodium–carbon bonds. The radical (chemistry), radical is found above or when trapped by cooling to liquid nitrogen temperatures (). At room temperature, pairs of these radicals join via their cyclopentadienyl rings to form a Dimer (chemistry), dimer, a yellow solid. The history of organometallic chemistry includes the 19th-century discoveries of Zeise's salt and nickel tetracarbonyl. These compounds posed a challenge to chemists as the compounds did not fit with existing chemical bonding models. A further challenge arose with the discovery of ferrocene, the iron analogue of rhodocene and the first of the class of compound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Chem Chem may refer to: Chemistry Chemical * ''Chem'' (journal), a scientific journal published by Cell Press Post apocalyptic slang for "drugs", medicinal or otherwise in the Fallout video game series. In Ancient Egyptian usage: ''Khem'' (also spelt ''Chem''), the Egyptian word for "black" Min (god), in the past erroneously named ''Khem'' CHEM may refer to : A metabolic panel: for instance, CHEM-7, which is the basic metabolic panel * CHEM-DT, a Canadian television channel See also * Chemo (other) * Kem (other) Kemi Kemi (; ; ; ) is a cities of Finland, town and municipalities of Finland, municipality of Finland. It is located approximately from the city of Tornio and the Finland–Sweden border, Swedish border. The distance to Oulu is to the south and t ... , a place in Finland {{disambig ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
	IARC Group 2B Carcinogens IARC group 2B substances, mixtures and exposure circumstances are those that have been classified as "possibly carcinogenic to humans" by the International Agency for Research on Cancer (IARC) as This category is used when there is level of evidence, limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is insufficient evidence of carcinogenicity in humans but sufficient evidence in experimental animals. In some cases, an agent, mixture, or exposure circumstance with inadequate evidence of carcinogenicity in humans but limited evidence in experimental animals, combined with supporting evidence from other relevant data, may be included in this group. This list focuses on the hazard linked to the agents. This means that the carcinogenic agents are capable of causing cancer, but this does not take their risk into account, which is the probability of causing a cancer given the level o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Metallocenes A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metallic element, 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 or vanadocene dichloride. Certain metallocenes and their derivatives exhibit catalysis, catalytic properties, although metallocenes are rarely used industrially. Cationic group 4 metallocene derivatives related to [Cp2ZrCH3]+ catalyze Ziegler–Natta catalyst, 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 aromaticity, aromatically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Organocobalt Compounds Organocobalt chemistry is the chemistry of organometallic compounds containing a carbon to cobalt chemical bond. Organocobalt compounds are involved in several organic reactions and the important biomolecule vitamin B12, vitamin B12 has a cobalt-carbon bond. Many organocobalt compounds exhibit useful catalytic properties, the preeminent example being dicobalt octacarbonyl. Alkyl complexes Most fundamental are the cobalt complexes with only alkyl ligands. Examples include Co(4-norbornyl)4 and its cation. Alkylcobalt is represented by vitamin B12, vitamin B12 and related enzymes. In methylcobalamin the ligand is a methyl group, which is electrophilic. in vitamin B12, the alkyl ligand is an adenosyl group. Related to vitamin B12 are cobalt porphyrins, dimethylglyoxime, dimethylglyoximates, and related complexes of Schiff base ligands. These synthetic compounds also form alkyl derivatives that undergo diverse reactions reminiscent of the biological processes. The weak cobalt(III) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Cyclopentadienylcobalt Dicarbonyl Cyclopentadienylcobalt dicarbonyl is an organocobalt compound with formula (C5H5)Co(CO)2, abbreviated CpCo(CO)2. It is an example of a half-sandwich complex. It is a dark red air sensitive liquid. This compound features one cyclopentadienyl ring that is bound in an η5-manner and two carbonyl ligands. The compound is soluble in common organic solvents. Preparation CpCo(CO)2 was first reported in 1954 by Piper, Cotton, and Wilkinson who produced it by the reaction of cobalt carbonyl with cyclopentadiene. It is prepared commercially by the same method: : Co2(CO)8 + 2 C5H6 → 2 C5H5Co(CO)2 + H2 + 4 CO Alternatively, it is generated by the high pressure carbonylation of bis(cyclopentadienyl)cobalt (cobaltocene) at elevated temperature and pressures: :Co(C5H5)2 + 2 CO → C5H5Co(CO)2 + "C5H5" The compound is identified by strong bands in its IR spectrum at 2030 and 1960 cm−1. Reactions CpCo(CO)2 catalyzes the cyclotrimerization of alkynes. The catalytic cycle begins wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Carbon Monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simplest oxocarbon, carbon oxide. In coordination complexes, the carbon monoxide ligand is called ''metal carbonyl, carbonyl''. It is a key ingredient in many processes in industrial chemistry. The most common source of carbon monoxide is the partial combustion of carbon-containing compounds. Numerous environmental and biological sources generate carbon monoxide. In industry, carbon monoxide is important in the production of many compounds, including drugs, fragrances, and fuels. Indoors CO is one of the most acutely toxic contaminants affecting indoor air quality. CO may be emitted from tobacco smoke and generated from malfunctioning fuel-burning stoves (wood, kerosene, natural gas, propane) and fuel-burning heating systems (wood, oil, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Half-reaction In chemistry, a half reaction (or half-cell reaction) is either the oxidation or reduction reaction component of a redox reaction. A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction. Often, the concept of half reactions is used to describe what occurs in an electrochemical cell, such as a Galvanic cell battery. Half reactions can be written to describe both the metal undergoing oxidation (known as the anode) and the metal undergoing reduction (known as the cathode). Half reactions are often used as a method of balancing redox reactions. For oxidation-reduction reactions in acidic conditions, after balancing the atoms and oxidation numbers, one will need to add ions to balance the hydrogen ions in the half reaction. For oxidation-reduction reactions in basic conditions, after balancing the atoms and oxidation numbers, first treat it as an acidic solution and then add ions to balance the ions in the hal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Ferrocenium Ferrocenium tetrafluoroborate is an organometallic compound with the formula e(C5H5)2F4. This salt is composed of the cation e(C5H5)2sup>+ and the tetrafluoroborate anion (). The related hexafluorophosphate is also a popular reagent with similar properties. The ferrocenium cation is often abbreviated Fc+ or Cp2Fe+. The salt is deep blue in color and paramagnetic. Ferrocenium salts are sometimes used as one-electron oxidizing agents, and the reduced product, ferrocene, is inert and readily separated from ionic products. The ferrocene–ferrocenium couple is often used as a reference in electrochemistry. The standard potential of ferrocene-ferrocenium is dependent on specific electrochemical conditions. Preparation Commercially available, this compound may be prepared by oxidizing ferrocene typically with ferric salts followed by addition of fluoroboric acid. A variety of other oxidants work well also, such as nitrosyl tetrafluoroborate. Many analogous ferrocenium salts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Reduction Potential Redox potential (also known as oxidation / reduction potential, ''ORP'', ''pe'', ''E_'', or E_) is a measure of the tendency of a chemical species to acquire electrons from or lose electrons to an electrode and thereby be reduced or oxidised respectively. Redox potential is expressed in volts (V). Each species has its own intrinsic redox potential; for example, the more positive the reduction potential (reduction potential is more often used due to general formalism in electrochemistry), the greater the species' affinity for electrons and tendency to be reduced. Measurement and interpretation In aqueous solutions, redox potential is a measure of the tendency of the solution to either gain or lose electrons in a reaction. A solution with a higher (more positive) reduction potential than some other molecule will have a tendency to gain electrons from this molecule (i.e. to be reduced by oxidizing this other molecule) and a solution with a lower (more negative) reduction potential w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Decamethylcobaltocene Decamethylcobaltocene is an organocobalt compound with the formula Co(C5(CH3)5)2, abbreviated CoCp{{su, p=∗, b=2. It is a dark brown solid. This compound is used as a strong reducing agent in organometallic chemistry. Synthesis Decamethylcobaltocene is prepared by treatment of LiCp* with CoCl2: :2 LiCp* + CoCl2 → 2 LiCl + CoCp2 The permethylated form is more air-sensitive than the parent cobaltocene, owing to the inductive effects of methyl groups. It is a thermally stable compound and undergoes vacuum sublimation. Bonding Co(C5Me5)2 is a metallocene, having idealized D5d symmetry. Like cobaltocene, decamethylcobaltocene has a 19 electron count in its valence shell and is paramagnetic. It is used as a one-electron reducing agent. Relative to the ferrocene/ferrocenium couple, the redox potential for the oCp2sup>+/0 couple is -1.94 V compared to the oCp2sup>+/0 couple of -1.33 V (in dichloromethane). For comparison, the difference between the redox ferrocene an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]