Diphenyl disulfide
From Wikipedia, the free encyclopedia
| Diphenyl disulfide | |
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| IUPAC name | Diphenyl disulfide |
| Other names | Phenyl disulfide |
| Identifiers | |
| CAS number | [882-33-7] |
| 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 | |
| Main hazards | Flammable |
| R-phrases | 36/37/38 |
| S-phrases | 26 |
| Related compounds | |
| Related compounds | C6H5SH, (CH3)2S2, Diphenyl diselenide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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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.
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[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 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
- ^ 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.
- ^ 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.
- ^ Thalmann, A. Oertle, K.; Gerlach, H. (1990). "Ricinelaidic Acid Lactone". Org. Synth.; Coll. Vol. 7: 470.
- ^ Field, L.; Locke, J. M. (1973). "Methyl Benzenesulfinate". Org. Synth.; Coll. Vol. 5: 723.
