Trisha Shetty (Editor)

1,2 Benzenedithiol

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Formula  C6H6S2
Density  1.24 g/cm³
Molar mass  142.24 g/mol
Appearance  colourless liquid
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1,2-Benzenedithiol is the organosulfur compound with the formula C6H4(SH)2. This colourless viscous liquid consists of a benzene ring with a pair of adjacent thiol groups. The conjugate base of this diprotic compound serves as chelating agent in coordination chemistry and a building block for the synthesis of other organosulfur compounds.



The compound is prepared by ortho-lithiation of benzenethiol using butyl lithium (BuLi) followed by sulfidation:

C6H5SH + 2 BuLi → C6H4SLi-2-Li + 2 BuH C6H4SLi-2-Li + S → C6H4(SLi)2 C6H4(SLi)2 + 2 HCl → C6H4(SH)2 + 2 LiCl

The compound was first prepared from 2-aminobenzenethiol via diazotization. Alternatively, it forms from 1,2-dibromobenzene.


Oxidation mainly affords the polymeric disulfide. Reaction with metal dihalides and metal oxides gives the dithiolate complexes of the formula LnM(S2C6H4) where LnM represents a variety of metal centers, e.g. (C5H5)2Ti. Ketones and aldehydes condense to give the heterocycles called dithianes:

C6H4(SH)2 + RR’CO → C6H4(S)2CRR’ + H2O

3,4-Toluenedithiol, also called dimercaptotoluene (CAS#496-74-2), behaves similarly to 1,2-benzenedithiol but is a solid at ambient temperatures (m.p. 135-137 °C).

Alkene-1,2-dithiols are unstable, although metal complexes of alkene-1,2-dithiolates, called dithiolene complexes, are well known.


1,2-Benzenedithiol Wikipedia