Diethylzinc

 ( Reagents For Organic Chemistry ) 

Diethylzinc, or DEZ, is an organozinc compound with the chemical formula . It is highly pyrophoric and reactive, consisting of a zinc center bound to two . This colourless liquid is an important reagent in organic chemistry. It is available commercially as a solution in , heptane, or toluene, or as a pure liquid.

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Synthesis Edward Frankland first reported the compound in 1848 from zinc and ethyl iodide, 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, a source of reactive zinc.

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Structure The compound crystallizes in a tetragonal body-centered unit cell of space group symmetry I4₁md. In the solid 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).

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Uses Despite its highly pyrophoric nature, diethylzinc is an important chemical reagent. It is used in organic synthesis as a source of the ethyl carbanion in addition reactions to carbonyl groups. For example, the asymmetric addition of an ethyl group to benzaldehyde and . Additionally, it is commonly used in combination with diiodomethane as a Simmons-Smith reagent to convert alkenes into cyclopropyl groups. It is less nucleophilic than related alkyllithium and , so it may be used when a "softer" nucleophile is needed. It is also used extensively in materials science chemistry as a zinc source in the synthesis of nanoparticles. Particularly in the formation of the zinc sulfide shell for core/shell-type quantum dots. While in polymer chemistry, it can be used as part of the catalyst for a chain shuttling polymerization reaction, whereby it participates in living polymerization.

Diethylzinc 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

(2025). 9780471326427, John Wiley & Sons, Inc.. . ISBN 9780471326427

—it ignites on contact with oxidizer, 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 as a potential means of mass deacidification of books printed on wood pulp paper. Diethylzinc vapour would, in theory, neutralize acid residues in the paper, leaving slightly zinc oxide residues. Although initial results were promising, the project was abandoned. A variety of adverse results prevented the method's adoption. Most infamously, the final prototype suffered damage in a series of diethylzinc explosions from trace amounts of water vapor in the chamber. This led the authors of the study to humorously comment: In microelectronics, diethylzinc is used as a doping agent.

For corrosion protection in nuclear reactors of the light water reactor design, depleted zinc oxide is produced by first passing diethylzinc through an enrichment centrifuge.

The pyrophoricity of diethylzinc can be used to test the inert atmosphere inside a glovebox. An oxygen concentration of only a few parts per million will cause a bottle of diethylzinc to fume when opened.

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Safety Diethylzinc may explode when mixed with water and can spontaneously pyrophoric. It should therefore be handled using air-free techniques.

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External links

• Demonstration of the ignition of diethylzinc in air Video - University of Nottingham

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