Dimethylzinc
Encyclopedia
Dimethylzinc, also known as Zinc methyl, DMZ, or DMZn is a colorless mobile liquid
Zn(CH3)2, formed by the action of methyl iodide on zinc
at elevated temperature or on zinc sodium alloy.
The sodium assists the reaction of the zinc with the methyl iodide. Zinc iodide is formed as a byproduct.
It has a disagreeable odor
, and is spontaneously flammable in air. It has been of great importance in the synthesis
of organic compounds. It is soluble in alkanes and often sold as a solution in hexanes.
It belongs to the large series of similar compounds
such as diethylzinc
.
during his work with Robert Bunsen
in 1849 at the University of Marburg. After heating a mixture of zinc and methyl iodide in an airtight vessel a flame bursted out after the seal was broken. In laboratory scale the synthesis method did not change till today, except that copper
or copper compounds are used to activate the zinc.
Its high vapor pressure has led to extensive uses in metalorganic chemical vapor deposition (MOCVD) for the preparation of wide band gap
II–VI semiconducting films (e.g. ZnO, ZnS
, ZnSe, ZnTe) and as p-dopant
precursors for III–V semiconductors (e.g. GaAs
, InP
, AlxGa1-xAs), which have many electronic
and photonic applications.
the compound exists in two modifications. The monoclinic high-temperature phase shows a two-dimensional disorder, while the low-temperature phase which is also monoclinic is ordered. The molecules are linear with Zn-C bond lengths measuring 1.927(6) pm. The structure of the gas-phase shows a very similar Zn-C distance of 193.0(2) pm.
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
Zn(CH3)2, formed by the action of methyl iodide on zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
at elevated temperature or on zinc sodium alloy.
- 2Zn + 2CH3I → Zn(CH3)2 + ZnI2
The sodium assists the reaction of the zinc with the methyl iodide. Zinc iodide is formed as a byproduct.
It has a disagreeable odor
Odor
An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...
, and is spontaneously flammable in air. It has been of great importance in the synthesis
Chemical synthesis
In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...
of organic compounds. It is soluble in alkanes and often sold as a solution in hexanes.
It belongs to the large series of similar compounds
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...
such as diethylzinc
Diethylzinc
Diethylzinc 2Zn, or DEZn, is a highly pyrophoric organozinc compound consisting of a zinc center bound to two ethyl groups. This colourless liquid is an important reagent in organic chemistry and available commercially as a solution in hexanes, heptane, or toluene.-Synthesis:Edward Frankland first...
.
History
This substance was first prepared by Edward FranklandEdward Frankland
Sir Edward Frankland, KCB, FRS was a chemist, one of the foremost of his day. He was an expert in water quality and analysis, and originated the concept of combining power, or valence, in chemistry. He was also one of the originators of organometallic chemistry.-Biography:Edward Frankland was born...
during his work with Robert Bunsen
Robert Bunsen
Robert Wilhelm Eberhard Bunsen was a German chemist. He investigated emission spectra of heated elements, and discovered caesium and rubidium with Gustav Kirchhoff. Bunsen developed several gas-analytical methods, was a pioneer in photochemistry, and did early work in the field of organoarsenic...
in 1849 at the University of Marburg. After heating a mixture of zinc and methyl iodide in an airtight vessel a flame bursted out after the seal was broken. In laboratory scale the synthesis method did not change till today, except that copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
or copper compounds are used to activate the zinc.
Uses
Dimethyl zinc was used for a long time to introduce methyl groups into organic molecules or to synthesize organometallic compounds containing methyl groups. Grignard reagents, (organo-magnesium compounds), which are easier to handle and less flammable replaced organo-zinc compounds in most laboratory syntheses. Due to differences in reactivity (as well as in reaction by-products) between organo-zinc compounds and Grignard reagents, organo-zinc compounds may be preferred in some syntheses.Its high vapor pressure has led to extensive uses in metalorganic chemical vapor deposition (MOCVD) for the preparation of wide band gap
Band gap
In solid state physics, a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference between the top of the valence band and the...
II–VI semiconducting films (e.g. ZnO, ZnS
ZNS
ZNS or ZnS may refer to:In entertainment:* ZNS , a popular entertainer in China and Chinese speaking parts of the world...
, ZnSe, ZnTe) and as p-dopant
Dopant
A dopant, also called a doping agent, is a trace impurity element that is inserted into a substance in order to alter the electrical properties or the optical properties of the substance. In the case of crystalline substances, the atoms of the dopant very commonly take the place of elements that...
precursors for III–V semiconductors (e.g. GaAs
Gaas
Gaas is a commune in the Landes department in Aquitaine in south-western France....
, InP
INP
INP may stand for:*INP , a Korean chemical company*INP , an early database system developed at the University of California, Berkeley*Integrated National Police, a forerunner of the Philippine National Police...
, AlxGa1-xAs), which have many electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
and photonic applications.
Structure
In the solid stateSolid state
Solid state may refer to:In science:* Solid-state chemistry* Solid-state physics* Solid-state laser* Solid matterIn electronics:* Solid state , circuits built of solid materials* Solid-state fan...
the compound exists in two modifications. The monoclinic high-temperature phase shows a two-dimensional disorder, while the low-temperature phase which is also monoclinic is ordered. The molecules are linear with Zn-C bond lengths measuring 1.927(6) pm. The structure of the gas-phase shows a very similar Zn-C distance of 193.0(2) pm.