A coordinate covalent bond, also known as a dative bond, dipolar bond, or coordinate bond is a kind of two-center, two-electron covalent bond in which the two electrons derive from the same atom. The bonding of metal ions to ligands involves this kind of interaction. This type of interaction is central to Lewis theory.
An ylide or ylid is a neutral dipolar molecule containing a formally negatively charged atom (usually a carbanion) directly attached to a heteroatom with a formal positive charge (usually nitrogen, phosphorus or sulfur), and in which both atoms have full octets of electrons. The result can be viewed as a structure in which two adjacent atoms are connected by both a covalent and an ionic bond; normally written X+–Y−. Ylides are thus 1,2-dipolar compounds, and a subclass of zwitterions. They appear in organic chemistry as reagents or reactive intermediates.
The phosphonium cation describes polyatomic cations with the chemical formula PR+
4. They are tetrahedral and generally colorless.
Vaska's complex is the trivial name for the chemical compound trans-carbonylchlorobis(triphenylphosphine)iridium(I), which has the formula IrCl(CO)[P(C6H5)3]2. This square planar diamagnetic organometallic complex consists of a central iridium atom bound to two mutually trans triphenylphosphine ligands, carbon monoxide and a chloride ion. The complex was first reported by J. W. DiLuzio and Lauri Vaska in 1961. Vaska's complex can undergo oxidative addition and is notable for its ability to bind to O2 reversibly. It is a bright yellow crystalline solid.
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to PPh3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether.
Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents.
In organometallic chemistry, a metallacycle is a derivative of a carbocyclic compound wherein a metal has replaced at least one carbon center; this is to some extent similar to heterocycles. Metallacycles appear frequently as reactive intermediates in catalysis, e.g. olefin metathesis and alkyne trimerization. In organic synthesis, directed ortho metalation is widely used for the functionalization of arene rings via C-H activation. One main effect that metallic atom substitution on a cyclic carbon compound is distorting the geometry due to the large size of typical metals.
Diphenylphosphine, also known as diphenylphosphane, is an organophosphorus compound with the formula (C6H5)2PH. This foul-smelling, colorless liquid is easily oxidized in air. It is a precursor to organophosphorus ligands for use as catalysts.
Transition metal hydrides are chemical compounds containing a transition metal bonded to hydrogen. Most transition metals form hydride complexes and some are significant in various catalytic and synthetic reactions. The term "hydride" is used loosely: some so-called hydrides are acidic (e.g., H2Fe(CO)4), whereas some others are hydridic, having H−-like character (e.g., ZnH2).
Organoiridium chemistry is the chemistry of organometallic compounds containing an iridium-carbon chemical bond. Organoiridium compounds are relevant to many important processes including olefin hydrogenation and the industrial synthesis of acetic acid. They are also of great academic interest because of the diversity of the reactions and their relevance to the synthesis of fine chemicals.
Dimethylphenylphosphine is an organophosphorus compound with a formula P(C6H5)(CH3)2. The phosphorus is connected to a phenyl group and two methyl groups, making it the simplest aromatic alkylphosphine. This colorless air sensitive liquid is commonly used as a ligand in transition metal complexes. These complexes are often soluble in organic solvents.
Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity.
Organoplatinum chemistry is the chemistry of organometallic compounds containing a carbon to platinum chemical bond, and the study of platinum as a catalyst in organic reactions. Organoplatinum compounds exist in oxidation state 0 to IV, with oxidation state II most abundant. The general order in bond strength is Pt-C (sp) > Pt-O > Pt-N > Pt-C (sp3). Organoplatinum and organopalladium chemistry are similar, but organoplatinum compounds are more stable and therefore less useful as catalysts.
Organorhodium chemistry is the chemistry of organometallic compounds containing a rhodium-carbon chemical bond, and the study of rhodium and rhodium compounds as catalysts in organic reactions.
Iron tetracarbonyl hydride is the organometallic compound with the formula H2Fe(CO)4. This compound was the first transition metal hydride discovered. The complex is stable at low temperatures but decomposes rapidly at temperatures above –20 °C.
Rhodocene is a chemical compound with the formula [Rh(C5H5)2]. Each molecule contains an atom of rhodium bound between two planar aromatic systems of five carbon atoms known as cyclopentadienyl rings in a sandwich arrangement. It is an organometallic compound as it has (haptic) covalent rhodium–carbon bonds. The [Rh(C5H5)2] radical is found above 150 °C or when trapped by cooling to liquid nitrogen temperatures (−196 °C). At room temperature, pairs of these radicals join via their cyclopentadienyl rings to form a dimer, a yellow solid.
In organometallic chemistry, a dicarbollide is an anion of the formula [C2B9H11]2-. Various isomers exist, but most common is 1,2-dicarbollide derived from ortho-carborane. These dianions function as ligands, related to the cyclopentadienyl anion. Substituted dicarbollides are also known such as [C2B9H10(pyridine)]− (pyridine bonded to B) and [C2R2B9H9]2- (R groups bonded to carbon).
In coordination chemistry phosphines are L-type ligands. Unlike most metal ammine complexes, metal phosphine complexes tend to be lipophilic, displaying good solubility in organic solvents. They also are compatible with metals in multiple oxidation states. Because of these two features, metal phosphine complexes are useful in homogeneous catalysis. Prominent examples of metal phosphine complexes include Wilkinson's catalyst (Rh(PPh3)3Cl), Grubbs' catalyst, and tetrakis(triphenylphosphine)palladium(0).
In organic chemistry, Wittig reagents are organophosphorus compounds of the formula R3P=CHR', where R is usually phenyl. They are used to convert ketones and aldehydes to alkenes:
Transition metal acyl complexes describes organometallic complexes containing one or more acyl (RCO) ligands. Such compounds occur as transient intermediates in many industrially useful reactions, especially carbonylations.
