Diethylzinc

• Zinc diethyl
• December

Colorless liquid

Liquid

1.21 g · cm -3

-28 ° C

117 ° C (1013 hPa)

21 hPa ( 20 ° C)

Reacts very violently with water

1.4936 (20 ° C)

Risk

Template: Infobox chemical / molecular formula search available

Diethylzinc, also known as zinc diethyl or DEZ is an organometallic compound composed of two ethyl groups bonded to zinc.

History

The chemist Edward Frankland (1825-1899) presented for the first time in 1848 from diethyl zinc and ethyl iodide ago. Frankland was working as a guest in the Marburg laboratory of Robert Bunsen. At that time, carbon dioxide was used as a shielding gas, which can be generated in the Kipp's apparatus. In many publications it is described as the first synthesis of an organometallic compound. However, there was previously other syntheses of organometallic compounds, such as 1840, the synthesis of Diethyltellur by Friedrich Wöhler in 1760 or that of the cacodyl by Louis Claude Cadet de Gassicourt. Later Frankland improved the synthesis by replacing the ethyl iodide by diethylmercury.

Representation and extraction

The synthesis of diethyl achieved by a transalkylation of triethylaluminum by zinc chloride to give the desired product can be separated off by distillation from the by-product of diethylaluminum chloride.

Another route to the preparation of diethyl zinc is the classic synthesis of ethyl iodide or ethyl bromide, with a zinc - copper couple ( activated zinc ).

Properties

Diethylzinc is a colorless liquid with an unpleasant odor. It reacts violently with water and is pyrophoric in air. The handle must therefore be carried out under a protective gas, for example nitrogen or argon.

Structure

The crystal structure of diethylzinc has a body-centered tetragonal unit cell (space group I41md ). The molecules form a polar crystal packing, with arranging the two ethyl groups in the cis position. The Zn -C bonds are 194.8 (5 ) pm long, while the C -Zn - C angle of 176.2 ( 4) ° is slightly bent. In the gas phase, the zinc atoms are coordinated linear. The Zn -C bonds be here 195.0 (2) pm.

Use

Diethylzinc is used for various applications in organic synthesis, since thus possible to produce highly functionalized materials, which are important starting materials for the preparation of pharmaceuticals, natural product derivatives, polymers, and many other compounds. In contrast to many other organometallic compounds diethylzinc tolerates a wide range of functional groups. Another advantage over other organometallic compounds is that diethylzinc often stereo -and regio- selectively reacts in the presence of suitable catalysts with organic compounds.

Diethylzinc is currently used in large quantities in the solar industry for the production of TCO layers of zinc oxide for thin-film solar cells.

Diethyl zinc acts as a nucleophilic ethyl synthon in addition reactions of carbonyl groups. With diiodomethane it forms the reactive agent in the Simmons-Smith reaction.

In a project of the Library of Congress in Washington DC DEC has been used for many years as a means for mass to protect valuable books and other documents before the acid decomposition. After an accident in which DEZ residues with moisture came in a preparation chamber for reaction and led to a detonation, the project was completed.