Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide, cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal phosphine complexes are representative members of this class. The field of organometallic chemistry combines aspects of traditional inorganic and organic chemistry.
In organic chemistry, an aldehyde is an organic compound containing a functional group with the structure R−CH=O. The functional group itself can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are a common motif in many chemicals important in technology and biology.
A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. Like all catalysts, they catalyze reverse as well as forward reactions, and in some cases this has physiological significance: for example, alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde in animals, but in yeast it catalyzes the production of ethanol from acetaldehyde.
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, often an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogenation reduces double and triple bonds in hydrocarbons.
Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms a hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are colourless crystals, but samples are often contaminated with iron(III) chloride, giving them a yellow colour.
Nickel(II) chloride (or just nickel chloride) is the chemical compound NiCl2. The anhydrous salt is yellow, but the more familiar hydrate NiCl2·6H2O is green. Nickel(II) chloride, in various forms, is the most important source of nickel for chemical synthesis. The nickel chlorides are deliquescent, absorbing moisture from the air to form a solution. Nickel salts have been shown to be carcinogenic to the lungs and nasal passages in cases of long-term inhalation exposure.
Butyraldehyde, also known as butanal, is an organic compound with the formula CH3(CH2)2CHO. This compound is the aldehyde derivative of butane. It is a colorless flammable liquid with an unpleasant smell. It is miscible with most organic solvents.
Iron(III) fluoride, also known as ferric fluoride, are inorganic compounds with the formula FeF3(H2O)x where x = 0 or 3. They are mainly of interest by researchers, unlike the related iron(III) chloride. Anhydrous iron(III) fluoride is white, whereas the hydrated forms are light pink.
The Dakin oxidation (or Dakin reaction) is an organic redox reaction in which an ortho- or para-hydroxylated phenyl aldehyde (2-hydroxybenzaldehyde or 4-hydroxybenzaldehyde) or ketone reacts with hydrogen peroxide (H2O2) in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidised, whereas the H2O2 is reduced.
In chemistry, transfer hydrogenation is a chemical reaction involving the addition of hydrogen to a compound from a source other than molecular H2. It is applied in laboratory and industrial organic synthesis to saturate organic compounds and reduce ketones to alcohols, and imines to amines. It avoids the need for high-pressure molecular H2 used in conventional hydrogenation. Transfer hydrogenation usually occurs at mild temperature and pressure conditions using organic or organometallic catalysts, many of which are chiral, allowing efficient asymmetric synthesis. It uses hydrogen donor compounds such as formic acid, isopropanol or dihydroanthracene, dehydrogenating them to CO2, acetone, or anthracene respectively. Often, the donor molecules also function as solvents for the reaction. A large scale application of transfer hydrogenation is coal liquefaction using "donor solvents" such as tetralin.
Oppenauer oxidation, named after Rupert Viktor Oppenauer, is a gentle method for selectively oxidizing secondary alcohols to ketones.
In chemistry, carbonylation refers to reactions that introduce carbon monoxide (CO) into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbonylation also refers to oxidation of protein side chains.
Asymmetric hydrogenation is a chemical reaction that adds two atoms of hydrogen to a target (substrate) molecule with three-dimensional spatial selectivity. Critically, this selectivity does not come from the target molecule itself, but from other reagents or catalysts present in the reaction. This allows spatial information to transfer from one molecule to the target, forming the product as a single enantiomer. The chiral information is most commonly contained in a catalyst and, in this case, the information in a single molecule of catalyst may be transferred to many substrate molecules, amplifying the amount of chiral information present. Similar processes occur in nature, where a chiral molecule like an enzyme can catalyse the introduction of a chiral centre to give a product as a single enantiomer, such as amino acids, that a cell needs to function. By imitating this process, chemists can generate many novel synthetic molecules that interact with biological systems in specific ways, leading to new pharmaceutical agents and agrochemicals. The importance of asymmetric hydrogenation in both academia and industry contributed to two of its pioneers — William Standish Knowles and Ryōji Noyori — being collectively awarded one half of the 2001 Nobel Prize in Chemistry.
Organoiron chemistry is the chemistry of iron compounds containing a carbon-to-iron chemical bond. Organoiron compounds are relevant in organic synthesis as reagents such as iron pentacarbonyl, diiron nonacarbonyl and disodium tetracarbonylferrate. While iron adopts oxidation states from Fe(−II) through to Fe(VII), Fe(IV) is the highest established oxidation state for organoiron species. Although iron is generally less active in many catalytic applications, it is less expensive and "greener" than other metals. Organoiron compounds feature a wide range of ligands that support the Fe-C bond; as with other organometals, these supporting ligands prominently include phosphines, carbon monoxide, and cyclopentadienyl, but hard ligands such as amines are employed as well.
Copper(II) tetrafluoroborate is any inorganic compound with the formula Cu(H2O)x(BF4)2. As usually encountered, it is assumed to be the hexahydrate (x = 6), but this salt can be partially dehydrated to the tetrahydrate. Regardless, these compounds are aquo complexes of copper in its +2 oxidation state, with two weakly coordinating tetrafluoroborate anions.
The Shvo catalyst is an organoruthenium compound that catalyzes the hydrogenation of polar functional groups including aldehydes, ketones and imines. The compound is of academic interest as an early example of a catalyst for transfer hydrogenation that operates by an "outer sphere mechanism". Related derivatives are known where p-tolyl replaces some of the phenyl groups. Shvo's catalyst represents a subset of homogeneous hydrogenation catalysts that involves both metal and ligand in its mechanism.
Hydrogen auto-transfer, also known as borrowing hydrogen, is the activation of a chemical reaction by temporary transfer of two hydrogen atoms from the reactant to a catalyst and return of those hydrogen atoms back to a reaction intermediate to form the final product. Two major classes of borrowing hydrogen reactions exist: (a) those that result in hydroxyl substitution, and (b) those that result in carbonyl addition. In the former case, alcohol dehydrogenation generates a transient carbonyl compound that is subject to condensation followed by the return of hydrogen. In the latter case, alcohol dehydrogenation is followed by reductive generation of a nucleophile, which triggers carbonyl addition. As borrowing hydrogen processes avoid manipulations otherwise required for discrete alcohol oxidation and the use of stoichiometric organometallic reagents, they typically display high levels of atom-economy and, hence, are viewed as examples of Green chemistry.
Cadmium tetrafluoroborate is an ionic, chemical compound with the formula Cd(BF4)2. It is a crystalline solid, which is colorless and odorless. Cadmium tetrafluoroborate is most frequently used in the industrial production of high-strength steels, its purpose being to prevent hydrogen absorption, a source of post-production cracking of the metal, in the treated steels. Another application of the chemistry of cadmium tetrafluoroborate is fine tuning of the size of cadmium telluride nanomaterials.
The Krische allylation involves the enantioselective iridium-catalyzed addition of an allyl group to an aldehyde or an alcohol, resulting in the formation of a secondary homoallylic alcohol. The mechanism of the Krische allylation involves primary alcohol dehydrogenation or, when using aldehyde reactants, hydrogen transfer from 2-propanol. Unlike other allylation methods, the Krische allylation avoids the use of preformed allyl metal reagents and enables the direct conversion of primary alcohols to secondary homoallylic alcohols.
Iron(II) nitrate is the nitrate salt of iron(II). It is commonly encountered as the green hexahydrate, Fe(NO3)2·6H2O, which is a metal aquo complex, however it is not commercially available unlike iron(III) nitrate due to its instability to air. The salt is soluble in water serves as a ready source of ferrous ions.
