Sodium 1,3-dithiole-2-thione-4,5-dithiolate explained

Sodium 1,3-dithiole-2-thione-4,5-dithiolate is the organosulfur compound with the formula Na₂C₃S₅, abbreviated Na₂dmit. It is the sodium salt of the conjugate base of the 4,5-bis(sulfanyl)-1,3-dithiole-2-thione. The salt is a precursor to dithiolene complexes and tetrathiafulvalenes.^[1]

Reduction of carbon disulfide with sodium affords sodium 1,3-dithiole-2-thione-4,5-dithiolate together with sodium trithiocarbonate:

4 Na + 4 CS₂ → Na₂C₃S₅ + Na₂CS₃Before the characterization of dmit^2-, reduction of CS₂ was thought to give tetrathiooxalate (Na₂C₂S₄).^[2]

The dianion C₃S₅^2- is purified as the tetraethylammonium salt of the zincate complex [Zn(C₃S₅)₂]^2-. This salt converts to the bis(thioester) upon treatment with benzoyl chloride:^{[3] [1]}

[N(C₂H₅)₄]₂[Zn(C₃S₅)₂] + 4 C₆H₅COCl → 2 C₃S₃(SC(O)C₆H₅)₂ + [N(C₂H₅)₄]₂[ZnCl₄]Cleavage of the thioester with sodium methoxide gives sodium 1,3-dithiole-2-thione-4,5-dithiolate:

C₃S₃(SC(O)C₆H₅)₂ + 2 NaOCH₃ → Na₂C₃S₅ + 2 C₆H₅CO₂MeNa₂dmit undergoes S-alkylation.^[4] Heating solutions of Na₂dmit gives the isomeric 1,2-dithioledithiolate.

References

1. Org. Synth.. 1996. 73. 270. 10.15227/orgsyn.073.0270. 4,5-Dibenzoyl-1,3-dithiole-1-thione.
2. Dietzsch, W. . Strauch, P. . Hoyer, E. . Thio-oxalates: Their Ligand Properties and Coordination Chemistry. Coord. Chem. Rev.. 1992. 121. 43–130. 10.1016/0010-8545(92)80065-Y.
3. G. S. Girolami, T. B. Rauchfuss and R. J. Angelici (1999) Synthesis and Technique in Inorganic Chemistry, University Science Books: Mill Valley, CA.
4. Niels Svenstrup . Jan Becher . The Organic Chemistry of 1,3-Dithiole-2-thione-4,5-dithiolate (DMIT). Synthesis. 1995. 1995. 3. 215–235. 10.1055/s-1995-3910. 196762382.