Dimanganese decacarbonyl
Encyclopedia
Dimanganese decacarbonyl is the chemical compound
with the formula
Mn2(CO)10. This metal carbonyl
is an important reagent
in the organometallic chemistry
of manganese
.
under CO
. A more efficient preparation entails reduction of anhydrous MnCl2
with sodium benzophenone
ketyl under 200 atmospheres of CO. The availability of inexpensive methylcyclopentadienyl manganese tricarbonyl
("MMT") has led to a low pressure route to Mn2(CO)10.
D4d, which is an uncommon symmetry.
techniques. It finds limited use in organic synthesis
.
Characteristic reactions:
The anion is a versatile nucleophile. Protonation gives the hydride
[HMn(CO)5], and methylation gives [(CH3)Mn(CO)5].
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
Mn2(CO)10. This metal carbonyl
Metal carbonyl
Metal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. These complexes may be homoleptic, that is containing only CO ligands, such as nickel carbonyl , but more commonly metal carbonyls contain a mix of ligands, such as Re3Cl...
is an important reagent
Reagent
A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
in the organometallic chemistry
Organometallic chemistry
Organometallic chemistry is the study of chemical compounds containing bonds between carbon and a metal. Since many compounds without such bonds are chemically similar, an alternative may be compounds containing metal-element bonds of a largely covalent character...
of manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
.
Synthesis
The compound was first prepared in low yield by the reduction of manganese iodide with magnesiumMagnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
under CO
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
. A more efficient preparation entails reduction of anhydrous MnCl2
Manganese(II) chloride
Manganese chloride describes a series of compounds with the formula MnCl2x, where the value of x can be 0, 2, or 4. The tetrahydrate is the most common form of "manganese chloride". MnCl2·4H2O, but the anhydrous form and dihydrate MnCl2·2H2O are also known...
with sodium benzophenone
Benzophenone
Benzophenone is the organic compound with the formula 2CO, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.-Uses:...
ketyl under 200 atmospheres of CO. The availability of inexpensive methylcyclopentadienyl manganese tricarbonyl
Methylcyclopentadienyl manganese tricarbonyl
Methylcyclopentadienyl manganese tricarbonyl is an organomanganese compound with the formula Mn3. Marketed initially in 1958 as a supplement to the gasoline additive tetraethyl lead to increase the fuel's octane rating, MMT was later used in unleaded gasoline...
("MMT") has led to a low pressure route to Mn2(CO)10.
Structure
Mn2(CO)10 has no bridging CO ligands: it can be described (CO)5Mn-Mn(CO)5. There are two kinds of CO ligands; one CO on each Mn is coaxial with the Mn-Mn bond, and four on each manganese that are perpendicular to it (equatorial). In the stable rotamer, the two Mn(CO)5 subunits are staggered. The overall molecule thus belongs to the point groupSymmetry group
The symmetry group of an object is the group of all isometries under which it is invariant with composition as the operation...
D4d, which is an uncommon symmetry.
Reactions
Mn2(CO)10 is air stable as a crystalline solid, but solutions require SchlenkSchlenk line
225px|thumb|Vacuum gas manifold set up: 1 inert gas in, 2 inert gas out , 3 vacuum 4 reaction line, 5 Teflon tap to gas, 6 Teflon tap to vacuum 225px|thumb| Vacuum gas manifold set up: 1 inert gas in, 2 inert gas out , 3 vacuum , 4 reaction line, 5 double oblique stopcock...
techniques. It finds limited use in organic synthesis
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
.
Characteristic reactions:
- Reduction of Mn2(CO)10 gives the manganese pentacarbonyl anion, which can be isolated as a saltSaltIn chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
:
- Mn2(CO)10 + 2 Na → 2 Na[Mn(CO)5]
The anion is a versatile nucleophile. Protonation gives the hydride
Hydride
In chemistry, a hydride is the anion of hydrogen, H−, or, more commonly, a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties. In compounds that are regarded as hydrides, hydrogen is bonded to a more electropositive element or group...
[HMn(CO)5], and methylation gives [(CH3)Mn(CO)5].
- Halogenation of Mn2(CO)10 proceeds with scission of the Mn-Mn bond.
- Mn2(CO)10 + Br2BromineBromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...
→ 2[Mn(CO)5Br]