Diphenyl disulfide 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 (C₆H₅S)₂. This colorless crystalline material is often abbreviated Ph₂S₂. It is one of the more commonly encountered organic

disulfide In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

s 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 ...

. Minor contamination by

thiophenol Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phen ...

is responsible for the disagreeable odour associated with this compound.

Preparation and structure

Diphenyl disulfide is usually prepared by the oxidation of

: : 2 PhSH + I₂ → Ph₂S₂ + 2 HI

Hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3 ...

can also be used as the oxidant. Ph₂S₂ is rarely prepared in the laboratory because it is inexpensive, and the precursor has a disagreeable odour. Like most organic disulfides, the C–S–S–C core of Ph₂S₂ is non-planar with a dihedral angle approaching 85°.

Reactions

Ph₂S₂ is mainly used in organic synthesis as a source of the PhS substituent. A typical reaction entails the formation of PhS-substituted carbonyl compounds via the enolate: :RC(O)CHLiR' + Ph₂S₂ → RC(O)CH(SPh)R' + LiSPh

Reduction

Ph₂S₂ undergoes reduction, a reaction characteristic of disulfides: :Ph₂S₂ + 2 M → 2 MSPh (M = Li, Na, K) Hydride reagents such as sodium borohydride and super hydride can also be used as reductants. The salts PhSM are sources of the potent

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ar ...

PhS⁻. Most alkyl halides, RX (X = halide) convert it to the thioethers with the general formula RSPh. Analogously, protonation of MSPh gives thiophenol: :PhSM + HCl → HSPh + MCl

Halogenation

Ph₂S₂ reacts with

chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...

to give phenylsulfenyl chloride PhSCl (

Zincke disulfide cleavage In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

). This species is usually generated and used '' in situ''. With

xenon difluoride Xenon difluoride is a powerful fluorinating agent with the chemical formula , and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with water vapor, but is otherwis ...

, Ph₂S₂ reacts to give

phenylsulfur pentafluoride Pentafluorosulfanylbenzene, or phenylsulfur pentafluoride, is an organosulfur compound with the formula C6H5SF5. It is colorless liquid with high chemical stability. Reactivity Pentafluorosulfanylbenzene possesses high chemical stability under a ...

Catalyst for photoisomerization of alkenes

Ph₂S₂ catalyzes the ''cis''-''trans'' isomerization of

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 ...

s under UV-irradiation.

Oxidation

Oxidation of Ph₂S₂ with lead(IV) acetate (Pb(OAc)₄) in

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is ...

affords the sulfinite ester PhS(O)OMe.

References

{{Reflist Organic disulfides Phenyl compounds