Benzeneselenol
Encyclopedia
Benzeneselenol is the chemical compound
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 C6H5SeH, often abbreviated PhSeH. This intensely malodorous liquid is a useful reagent 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...

.

Synthesis and basic properties

PhSeH is prepared via the reaction of phenylmagnesium bromide
Phenylmagnesium bromide
Phenylmagnesium bromide, with the simplified formula , is a magnesium-containing organometallic compound. It is so commonly used that it is commercially available as a solution in diethyl ether or tetrahydrofuran . Phenylmagnesium bromide is a Grignard reagent...

 and selenium
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...

:


More so than thiophenol, benzeneselenol is easily oxidized by air to give diphenyl diselenide
Diphenyl diselenide
Diphenyl diselenide is the chemical compound with the formula 2Se2, abbreviated Ph2Se2 This orange-coloured solid is the oxidized derivative of benzeneselenol...

. An idealized equation for this reaction is:
2 PhSeH + O → PhSeSePh + H2O


The presence of the diselenide is signaled by a yellow coloration in most samples of PhSeH. The diselenide can be converted back to the selenol by reduction followed by acidification of the resulting PhSe.

PhSeH is approximately seven times more acidic than the related thiophenol
Thiophenol
Thiophenol is an organosulfur compound with the formula C6H6S, and sometimes abbreviated as PhSH. This foul-smelling colourless liquid is the simplest aromatic thiol. The chemical structures of thiophenols are analogous to phenols except the oxygen atom in the hydroxyl group bonded to the...

. Both compounds dissolve in water upon the addition of base.

PhSeH is renowned 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 the precursor to its conjugate base PhSe, a potent nucleophile
Nucleophile
A nucleophile is a species that donates an electron-pair to an electrophile to form a chemical bond in a reaction. All molecules or ions with a free pair of electrons can act as nucleophiles. Because nucleophiles donate electrons, they are by definition Lewis bases.Nucleophilic describes the...

.

History

Benzeneselenol was first prepared by the reaction of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 with SeCl4
Selenium tetrachloride
Selenium tetrachloride is the inorganic compound composed with the formula SeCl4. This compound exists as yellow to white volatile solid. It is one of two commonly available selenium chlorides, the other example being selenium monochloride, Se2Cl2...

 in the presence of AlCl3.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK