Benzene-1,2-dithiol

Benzene-1,2-dithiol
Names
	Preferred IUPAC name Benzene-1,2-dithiol
	Other names 1,2-Dimercaptobenzene
Identifiers
CAS Number	17534-15-5 ;
3D model (JSmol)	Interactive image; Interactive image;
ChemSpider	13840080 ;
ECHA InfoCard	100.037.740
PubChem CID	69370;
UNII	F7M2QCZ9RB ;
CompTox Dashboard (EPA)	DTXSID20871274 ;
	InChI InChI=1S/C6H6S2/c7-5-3-1-2-4-6(5)8/h1-4,7-8H Key: JRNVQLOKVMWBFR-UHFFFAOYSA-N ; InChI=1/C6H6S2/c7-5-3-1-2-4-6(5)8/h1-4,7-8H Key: JRNVQLOKVMWBFR-UHFFFAOYAM;
	SMILES C1=CC=C(C(=C1)S)S; Sc1ccccc1S;
Properties
Chemical formula	C6H6S2
Molar mass	142.24 g/mol
Appearance	colourless liquid
Density	1.236 g/mL
Melting point	22 to 24 °C (72 to 75 °F; 295 to 297 K)
Boiling point	119 to 120 °C (246 to 248 °F; 392 to 393 K) at 17 mmHg
Solubility in water	Soluble in basic water
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	stench
Flash point	104.0 °C; 219.2 °F; 377.1 K
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Benzene-1,2-dithiol 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.^[1]

Synthesis

The compound is prepared by ortho-lithiation of benzenethiol using butyl lithium (BuLi) followed by sulfidation:^[2]

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.^[3] Alternatively, it forms from 1,2-dibromobenzene.^[4]

Reactions

Oxidation mainly affords the polymeric disulfide. Reaction with metal dihalides and metal oxides gives the dithiolate complexes of the formula L_nM(S₂C₆H₄) where L_nM 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

Related compounds

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]

References

^ ^a ^b Karlin, K. D.; Stiefel, E. I., Eds. “Progress in Inorganic Chemistry, Dithiolene Chemistry: Synthesis, Properties, and Applications” Wiley-Interscience: New York, 2003. ISBN 0-471-37829-1
^ D. M. Giolando; K. Kirschbaum (1992). "An efficient one-pot synthesis of 1,2-benzenedithiol from benzenethiol". Synthesis. 1992 (5): 451–452. doi:10.1055/s-1992-26132.
^ P. C. Guha; M. N. Chakladar (1925). "Dithiocatechol". J. Indian Chem. Soc. 2: 318.
^ Aldo Ferretti. "1,2-Dimercaptobenzene". Organic Syntheses; Collected Volumes, vol. 5, p. 419.

[Stiefel-1] Karlin, K. D.; Stiefel, E. I., Eds. “Progress in Inorganic Chemistry, Dithiolene Chemistry: Synthesis, Properties, and Applications” Wiley-Interscience: New York, 2003. ISBN 0-471-37829-1

[2] D. M. Giolando; K. Kirschbaum (1992). "An efficient one-pot synthesis of 1,2-benzenedithiol from benzenethiol". Synthesis. 1992 (5): 451–452. doi:10.1055/s-1992-26132.

[3] P. C. Guha; M. N. Chakladar (1925). "Dithiocatechol". J. Indian Chem. Soc. 2: 318.

[4] Aldo Ferretti. "1,2-Dimercaptobenzene". Organic Syntheses; Collected Volumes, vol. 5, p. 419.

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