Diphenyl disulfide
IUPAC name	Diphenyl disulfide
Other names	Phenyl disulfide
Identifiers
CAS number	882-33-7 Y
RTECS number	SS6825000
SMILES	C1(SSC2=CC=CC=C2)=CC=CC=C1
Properties
Molecular formula	C12H10S2
Molar mass	218.36 g/mol
Appearance	Colourless crystals
Density	? g/cm3
Melting point	61–62 °C
Solubility in water	Insoluble
Solubility in other solvents	Diethyl ether, Benzene, Carbon disulfide, THF
Structure
Dipole moment	0 D
Hazards
R-phrases	36/37/38
S-phrases	26
Related compounds
Related compounds	C6H5SH, (CH3)2S2, Diphenyl diselenide
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Diphenyl disulfide is the chemical compound with the formula [C₆H₅S]₂. This colorless crystalline material is often abbreviated Ph₂S₂. It is one of the most popular organic disulfides used in organic synthesis. Minor contamination by thiophenol is responsible for the disagreeable odour associated with this compound.

Contents 1 Preparation and structure 2 Reactions 2.1 Reduction 2.2 Chlorination 2.3 Catalyst for photoisomerisation of alkenes 2.4 Oxidation 3 References

[edit] Preparation and structure

Ph₂S₂ is usually prepared by the oxidation of thiophenol:

2 PhSH + I₂ → Ph₂S₂ + 2 HI

Hydrogen peroxide can also be used as the oxidant.^[1] Ph₂S₂ is rarely prepared in the laboratory because it is inexpensive, and the precursor has a disagreeable odour.

Like most organic disulfides, the C₂S₂ core of Ph₂S₂ is non-planar with a dihedral angle approaching 85°.

[edit] Reactions

Ph₂S₂ is mainly used in organic synthesis as a source of the PhS substituent.^[2] A typical reaction entails the formation of PhS-substituted carbonyl compounds via the enolate:

RC(O)CHLiR’ + Ph₂S₂ → RC(O)CH(SPh)R’ + LiSPh

[edit] 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 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

[edit] Chlorination

Ph₂S₂ reacts with chlorine to give phenylsulfenyl chloride PhSCl (Zincke disulfide cleavage). This species is somewhat difficult to isolate, so it is usually generated in situ.

[edit] Catalyst for photoisomerisation of alkenes

Ph₂S₂catalyzes the cis-trans isomerization of alkenes under UV-irradiation.^[3]

[edit] Oxidation

Oxidation of Ph₂S₂ with lead(IV) acetate (Pb(OAc)₄) in methanol affords the sulfinite ester PhS(O)OMe.^[4]

[edit] References

1. ^ Ravikumar,K. S.; Kesavan, V.; Crousse, B.; Bonnet-Delpon, D.; Bégué, J.-P. (2003), "Mild and Selective Oxidation of Sulfur Compounds in Trifluoroethanol: Diphenyl Disulfide and Methyl Phenyl Sulfoxide", Org. Synth. 80: 184, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=v80p0184 
2. ^ Byers, J. H. "Diphenyl Disulfide" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
3. ^ Thalmann, A. Oertle, K.; Gerlach, H. (1990), "Ricinelaidic Acid Lactone", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv7p0470 ; Coll. Vol. 7: 470 
4. ^ Field, L.; Locke, J. M. (1973), "Methyl Benzenesulfinate", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv5p0723 ; Coll. Vol. 5: 723