A metallocene is a compound typically consisting of two cyclopentadienyl anions (C
5H−
5, abbreviated Cp) bound to a metal center (M) in the oxidation state II, with the resulting general formula (C5H5)2M. Closely related to the metallocenes are the metallocene derivatives, e.g. titanocene dichloride or vanadocene dichloride. Certain metallocenes and their derivatives exhibit catalytic properties, although metallocenes are rarely used industrially. Cationic group 4 metallocene derivatives related to [Cp2ZrCH3]+ catalyze olefin polymerization.
Ferrocene is an organometallic compound with the formula Fe(C5H5)2. The molecule is a complex consisting of two cyclopentadienyl rings sandwiching 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 Fe(C5H5)+2. Ferrocene and the ferrocenium cation are sometimes abbreviated as Fc and Fc+ respectively.
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.
In organometallic chemistry, a sandwich compound is a chemical compound featuring a metal bound by haptic, covalent bonds to two arene (ring) ligands. The arenes have the formula CnHn, substituted derivatives and heterocyclic derivatives. Because the metal is usually situated between the two rings, it is said to be "sandwiched". A special class of sandwich complexes are the metallocenes.
1,1′-Bis(diphenylphosphino)ferrocene, commonly abbreviated dppf, is an organophosphorus compound commonly used as a ligand in homogeneous catalysis. It contains a ferrocene moiety in its backbone, and is related to other bridged diphosphines such as 1,2-bis(diphenylphosphino)ethane (dppe).
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.
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. 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.
Ferrocenium tetrafluoroborate is an organometallic compound with the formula [Fe(C5H5)2]BF4. This salt is composed of the cation [Fe(C5H5)2]+ and the tetrafluoroborate anion (BF−
4). 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.
Ferrocenium hexafluorophosphate is an organometallic compound with the formula [Fe(C5H5)2]PF6. This salt is composed of the cation [Fe(C5H5)2]+ and the hexafluorophosphate anion (PF−
6). The related tetrafluoroborate 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.
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 (302 °F) or when trapped by cooling to liquid nitrogen temperatures (−196 °C [−321 °F]). At room temperature, pairs of these radicals join via their cyclopentadienyl rings to form a dimer, a yellow solid.
Acetylferrocene is the organoiron compound with the formula (C5H5)Fe(C5H4COCH3). It consists of ferrocene substituted by an acetyl group on one of the cyclopentadienyl rings. It is an orange, air-stable solid that is soluble in organic solvents.
Decamethylferrocene or bis(pentamethylcyclopentadienyl)iron(II) is a chemical compound with formula Fe(C5(CH3)5)2 or C20H30Fe. It is a sandwich compound, whose molecule has an iron(II) cation Fe2+ attached by coordination bonds between two pentamethylcyclopentadienyl anions (Cp*−, (CH3)5C−5). It can also be viewed as a derivative of ferrocene, with a methyl group replacing each hydrogen atom of its cyclopentadienyl rings. The name and formula are often abbreviated to DmFc, Me10Fc or FeCp*2.
Decamethylcobaltocene is an organocobalt compound with the formula Co(C5(CH3)5)2, abbreviated CoCp∗
2. It is a dark brown solid. This compound is used as a strong reducing agent in organometallic chemistry.
N,N-Dimethylaminomethylferrocene is the dimethylaminomethyl derivative of ferrocene, (C5H5)Fe(C5H4CH2N(CH3)2. It is an air-stable, dark-orange syrup that is soluble in common organic solvents. The compound is prepared by the reaction of ferrocene with formaldehyde and dimethylamine:
Organotechnetium chemistry is the science of describing the physical properties, synthesis, and reactions of organotechnetium compounds, which are organometallic compounds containing carbon-to-technetium chemical bonds. The most common organotechnetium compounds are coordination complexes used as radiopharmaceutical imaging agents.
1,1'-Dilithioferrocene is the organoiron compound with the formula Fe(C5H4Li)2. It is exclusively generated and isolated as a solvate, using either ether or tertiary amine ligands bound to the lithium centers. Regardless of the solvate, dilithioferrocene is used commonly to prepare derivatives of ferrocene.
Ferrocenecarboxylic acid is the organoiron compound with the formula (C5H5)Fe(C5H4CO2H). It is the simplest carboxylic acid derivative of ferrocene. It can be prepared in two steps from ferrocene by acylation with a 2-chlorobenzoyl chloride followed by hydrolysis.
1,1'-Ferrocenedicarboxylic acid is the organoiron compound with the formula Fe(C5H4CO2H)2. It is the simplest dicarboxylic acid derivative of ferrocene. It is a yellow solid that is soluble in aqueous base. The 1,1' part of its name refers to the location of the carboxylic acid groups on separate rings.
1,1'-Ferrocenediisocyanate (1,1'-diisocyanatoferrocene) is the organoiron compound with the formula Fe(C5H4NCO)2. It is the simplest diisocyanate derivative of ferrocene. It can be synthesized by the Curtius rearrangement of the diacyl azide, using several protocols starting from 1,1'-ferrocenedicarboxylic acid. The compound is useful as an intermediate in the synthesis of 1,1'-diaminoferrocene by hydrolysis of the isocyanates. Various poly(siloxane–urethane) crosslinked polymers can be formed by reaction with siloxane-diols. These compounds are of interest as electrochemically active polymers that might have good mechanical properties at low temperature.
A molecular electron-reservoir complex is one of a class of redox-active systems which can store and transfer electrons stoichiometrically or catalytically without decomposition. The concept of electron-reservoir complexes was introduced by the work of French chemist, Didier Astruc. From Astruc's discoveries, a whole family of thermally stable, neutral, 19-electron iron(I) organometallic complexes were isolated and characterized, and found to have applications in redox catalysis and electrocatalysis. The following page is a reflection of the prototypal electron-reservoir complexes discovered by Didier Astruc.
