Diphenyl diselenide is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula (C₆H₅)₂Se₂, abbreviated Ph₂Se₂. This orange-coloured solid is the oxidized derivative of

benzeneselenol Benzeneselenol, also known as selenophenol, is the organoselenium compound with the formula C6H5SeH, often abbreviated PhSeH. It is the selenium analog of phenol. This colourless, malodorous compound is a reagent in organic synthesis. Synthesis ...

. It is used as a source of the PhSe unit in

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

Preparation and properties

Ph₂Se₂ is prepared by the oxidation of benzeneselenoate, the conjugate base of benzeneselenol which is generated via the

Grignard reagent A Grignard reagent or Grignard compound is a chemical compound with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide ...

: : PhMgBr + Se → PhSeMgBr :2 PhSeMgBr + Br₂ → Ph₂Se₂ + 2 MgBr₂ The molecule has idealized C₂-symmetry, like hydrogen peroxide and related molecules. The Se-Se bond length of 2.29 Å the C-Se-Se-C dihedral angle is 82° and the C-Se-Se angles are near 110°.

Antioxidant action

"Dietary supplementation with Ph₂Se₂ prevented CH₃HgCl-induced locomotor impairment. This effect appeared to be mediated by antioxidant action. Ph₂Se₂ may be a viable approach to prevention or reduction CH₃HgCl-mediated neurotoxic effects." The protective effects of diphenyl diselenide against methylmercury toxicity depends on the species considered, for instance, in mice the co-administration of diselenide and methylmercury decreased the mice Hg body burden [Leão MB, da Rosa PCC, Wagner C, Lugokenski TH, Dalla Corte CL. Methylmercury and diphenyl diselenide interactions in Drosophila melanogaster: effects on development, behavior, and Hg levels. Environ Sci Pollut Res Int. 2018 Aug;25(22):21568-21576. doi: 10.1007/s11356-018-2293-7. de Freitas AS, Funck VR, Rotta Mdos S, Bohrer D, Mörschbächer V, Puntel RL, Nogueira CW, Farina M, Aschner M, Rocha JB. Diphenyl diselenide, a simple organoselenium compound, decreases methylmercury-induced cerebral, hepatic and renal oxidative stress and mercury deposition in adult mice. Brain Res Bull. 2009 Apr 6;79(1):77-84. doi: 10.1016/j.brainresbull.2008.11.001. Dalla Corte CL, Wagner C, Sudati JH, Comparsi B, Leite GO, Busanello A, Soares FA, Aschner M, Rocha JB. Effects of diphenyl diselenide on methylmercury toxicity in rats. Biomed Res Int. 2013;2013:983821. doi: 10.1155/2013/983821. Lovato FL, Teixeira da Rocha JB, Dalla Corte CL. Diphenyl Diselenide Protects against Methylmercury-Induced Toxicity in Saccharomyces cerevisiae via the Yap1 Transcription Factor. Chem Res Toxicol. 2017 May 15;30(5):1134-1144. doi: 10.1021/acs.chemrestox.6b00449. ], but in rats it increased the deposition of Hg in muscle and brain. In rats, diphenyl diselenide further impaired the neurotoxic behavioral effects of methylmercury [de Freitas et al. 2009; Dalla Corte et al. 2013]

Reactions

A reaction characteristic of Ph₂Se₂ is its reduction: :Ph₂Se₂ + 2 Na → 2 PhSeNa PhSeNa is a useful nucleophile used to introduce the phenylselenyl group by

nucleophilic substitution In chemistry, a nucleophilic substitution is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile). The ...

alkyl halides The haloalkanes (also known as halogenoalkanes or alkyl halides) are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely us ...

, alkyl sulfonates ( mesylates or

tosyl In organic chemistry, a toluenesulfonyl group (tosyl group, abbreviated Ts or Tos) is a univalent functional group with the chemical formula –. It consists of a tolyl group, –, joined to a sulfonyl group, ––, with the open valence on s ...

ates) and

epoxide In organic chemistry, an epoxide is a cyclic ether () with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale for ...

s. The example below was taken from a synthesis of morphine. : NaSePh-Epoxide1

Another characteristic reaction is

chlorination Chlorination may refer to: * Chlorination reaction In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transform ...

: :Ph₂Se₂ + Cl₂ → 2 PhSeCl PhSeCl is a powerful electrophile, used to introduce PhSe groups by reaction with a variety of nucleophiles, including

enolates In organic chemistry, enolates are organic anions derived from the deprotonation of carbonyl () compounds. Rarely isolated, they are widely used as reagents in the synthesis of organic compounds. Bonding and structure Enolate anions are electr ...

, enol silyl ethers,

organolithium reagent In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom ...

alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...

s and

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituen ...

s. In the sequence below (early steps in the synthesis of Strychnofoline), a PhSe group is introduced by reaction of a

lactam A lactam is a cyclic amide, formally derived from an amino alkanoic acid. The term is a portmanteau of the words ''lactone'' + ''amide''. Nomenclature Greek prefixes in alphabetical order indicate ring size: * α-Lactam (3-atom rings) * β-Lacta ...

enolate with PhSeCl. This sequence is a powerful method for the conversion of

carbonyl compound 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. A compound containing a ...

s to their α,β-unsaturated analogs. : ClSePh-enone1

Diphenyl diselenide itself is also a source of a weakly electrophilic PhSe group in reactions with relatively powerful nucleophiles like Grignard reagents, lithium reagents and ester enolates (but not ketone enolates or weaker nucleophiles). PhSeCl is both more reactive, and more efficient, since with Ph₂Se₂ half of the selenium is wasted. :Ph₂Se₂ + Nu⁻ → PhSeNu + PhSe⁻ ''N''-Phenylselenophthalimide (N-PSP) can be used if PhSeCl is too strong and diphenyl diselenide is too weak or wasteful.

References

{{DEFAULTSORT:Diphenyl Diselenide Organoselenium compounds Phenyl compounds