Diethylzinc
Encyclopedia
Diethylzinc2Zn, or DEZn, is a highly pyrophoric organozinc compound
Organozinc compound
Organozinc compounds in organic chemistry contain carbon to zinc chemical bonds. Organozinc chemistry is the science of organozinc compounds describing their physical properties, synthesis and reactions....

 consisting of a zinc center bound to two ethyl group
Ethyl group
In chemistry, an ethyl group is an alkyl substituent derived from ethane . It has the formula -C2H5 and is very often abbreviated -Et.Ethylation is the formation of a compound by introduction of the ethyl functional group, C2H5....

s. This colourless liquid 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 organic chemistry
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...

 and available commercially as a solution in hexane
Hexane
Hexane is a hydrocarbon with the chemical formula C6H14; that is, an alkane with six carbon atoms.The term may refer to any of four other structural isomers with that formula, or to a mixture of them. In the IUPAC nomenclature, however, hexane is the unbranched isomer ; the other four structures...

s, heptane
Heptane
n-Heptane is the straight-chain alkane with the chemical formula H3C5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale...

, or toluene
Toluene
Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. It is a mono-substituted benzene derivative, i.e., one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3.It is an aromatic...

.

Synthesis

Edward Frankland
Edward 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...

 first reported the compound in 1848 from zinc and ethyl iodide
Ethyl iodide
Ethyl iodide is a colorless, flammable chemical compound. It has the chemical formula C2H5I and is prepared by heating ethanol with iodine and phosphorus. On contact with air, especially on the effect of light, it decomposes and turns yellow or reddish from dissolved iodine.Ethyl iodide is very...

, the first organozinc compound discovered. He improved the synthesis by using diethyl mercury as starting material The contemporary synthesis consists of the reaction of a 1:1 mixture of ethyl iodide and ethyl bromide with a zinc-copper couple
Zinc-copper couple
Zinc-copper couple is an alloy of zinc and copper that is employed as a reagent in organic synthesis. The “couple” was popularized after the report by Simmons and Smith in 1959 of its application as an activated source of zinc required for formation of an organozinc reagent in the Simmons-Smith...

, a source of reactive zinc.

Structure

The compound crystallizes in a tetragonal body-centered unit cell of space group
Space group
In mathematics and geometry, a space group is a symmetry group, usually for three dimensions, that divides space into discrete repeatable domains.In three dimensions, there are 219 unique types, or counted as 230 if chiral copies are considered distinct...

 symmetry I41md. In the solid-state diethylzinc shows nearly linear Zn centres. The Zn-C bonds measure 194.8(5) pm, while the C-Zn-C angle is slightly bent with 176.2(4)°. The structure of the gas-phase shows a very similar Zn-C distance (195.0(2) pm).

Uses

Despite its highly pyrophoric nature, diethylzinc is an important chemical reagent. It is used 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...

 as a source of the ethyl carbanion
Carbanion
A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons. The carbanion exists in a trigonal pyramidal geometry. Formally a carbanion is the conjugate base of a carbon acid.where B...

 in addition reaction
Addition reaction
An addition reaction, in organic chemistry, is in its simplest terms an organic reaction where two or more molecules combine to form a larger one....

s to carbonyl
Carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups....

 groups. For example, the asymmetric addition of an ethyl group
Ethyl group
In chemistry, an ethyl group is an alkyl substituent derived from ethane . It has the formula -C2H5 and is very often abbreviated -Et.Ethylation is the formation of a compound by introduction of the ethyl functional group, C2H5....

 to benzaldehyde
Benzaldehyde
Benzaldehyde is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful. This colorless liquid has a characteristic pleasant almond-like odor...

 and imine
Imine
An imine is a functional group or chemical compound containing a carbon–nitrogen double bond, with the nitrogen attached to a hydrogen atom or an organic group. If this group is not a hydrogen atom, then the compound is known as a Schiff base...

s.
Additionally, it is commonly used in combination with diiodomethane
Diiodomethane
Diiodomethane or methylene iodide, commonly abbreviated "MI", is a liquid organoiodine compound. It is insoluble in water, but soluble in ether and alcohol. It has a relatively high refractive index of 1.741, and a surface tension of 0.0508 N·m−1...

 as a Simmons-Smith reagent to convert alkenes into cyclopropyl groups.. It is less nucleophilic than related alkyllithium and Grignard reagents, so it may be used when a "softer" nucleophile is needed.
It is also used extensively in materials science chemistry
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...

 as a 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...

 source in the synthesis of nanoparticles. Particularly in the formation of the zinc sulfide
Zinc sulfide
Zinc sulfide is a inorganic compound with the formula ZnS. ZnS is the main form of zinc in nature, where it mainly occurs as the mineral sphalerite...

 shell for core/shell-type quantum dots.
While in polymer chemistry
Polymer chemistry
Polymer chemistry or macromolecular chemistry is a multidisciplinary science that deals with the chemical synthesis and chemical properties of polymers or macromolecules. According to IUPAC recommendations, macromolecules refer to the individual molecular chains and are the domain of chemistry...

, it can be used as part of the catalyst for a chain shuttling polymerization
Chain shuttling polymerization
Chain Shuttling Polymerization is a dual-catalyst method for producing block copolymers with alternating or variable tacticity. The desired effect of this method is to generate hybrid polymers that bear the properties of both polymer chains, such as a high melting point accompanied by high...

 reaction, whereby it participates in living polymerization.

Diethyl zinc is not limited to only being used in chemistry. Because of its high reactivity toward air, it was used in small quantities as a hypergolic or "self igniting" liquid rocket fuel -- it ignites on contact with oxidiser, so the rocket motor need only contain a pump, without a spark source for ignition. Diethylzinc was also investigated by the United States Library of Congress
Library of Congress
The Library of Congress is the research library of the United States Congress, de facto national library of the United States, and the oldest federal cultural institution in the United States. Located in three buildings in Washington, D.C., it is the largest library in the world by shelf space and...

 as a potential means of mass deacidification
Mass deacidification
Mass deacidification is a term used in Library and Information Science for one possible measure against the degradation of paper in old books . The goal of the process is to increase the pH of acidic paper on a large scale...

 of books printed on wood pulp paper. Vapor of diethylzinc vapour would in theory, neutralize acid residues in the paper, leaving slightly alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

ne zinc oxide
Zinc oxide
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...

 residues. Although initial results were promising, the project was abandoned. A variety of adverse results prevented the methods adoption. Most infamously, the final prototype suffered damage in a series of explosions from contact between trace amounts of diethylzinc and water vapor in the chamber. This lead the authors of the study to humorously comment:
In microelectronics, diethylzinc is used as a doping agent
Doping (semiconductor)
In semiconductor production, doping intentionally introduces impurities into an extremely pure semiconductor for the purpose of modulating its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductors are referred to as extrinsic...

.

Safety

Diethylzinc reacts violently with water and easily ignites upon contact with air. It should therefore be handled using inert atmosphere techniques.

External links

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