Dithiete

Dithiete is an unsaturated heterocyclic compound that contains two adjacent sulfur atoms and two sp²-hybridized carbon centers. Derivatives are known collectively as dithietes or 1,2-dithietes. With 6 π electrons, 1,2-dithietes are examples of aromatic organosulfur compounds. A few 1,2-dithietes have been isolated;^[1][2][3] one (low-yielding) route is oxidation of a dithiolene complex.^[4] 3,4-Bis(trifluoromethyl)-1,2-dithiete is a particularly stable example.

Dithiete

Kekulé, skeletal formula of dithiete with all explicit hydrogens added
Names
Preferred IUPAC name 1,2-Dithiete
Systematic IUPAC name 1,2-Dithiacyclobut-3-ene
Other names Dithiete Dithiacyclobutene 1,2-Dithia[4]annulene
Identifiers
CAS Number	7092-01-5
3D model (JSmol)	Interactive image Interactive image
ChemSpider	122516 Y
PubChem CID	138918
CompTox Dashboard (EPA)	DTXSID70221149
InChI InChI=1S/C2H2S2/c1-2-4-3-1/h1-2H Y Key: CTGHONDBXRRMRC-UHFFFAOYSA-N Y
SMILES c1css1 S1SC=C1
Properties
Chemical formula	C2H2S2
Molar mass	90.16 g·mol−1
Related compounds
Related thietes	Thiete
Related compounds	Thiirene 2,3-Dihydrothiophene Thiophene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Unsubstituted 1,2-dithiete has been generated in thermolytic reactions and was characterized by microwave spectroscopy, ultraviolet photoelectron spectroscopy and infrared spectroscopy in a low temperature matrix. The open ring isomer, dithioglyoxal, HC(S)C(S)H, is less stable than the 1,2-dithiete.^[5]

The dithione can be prepared (as trans-dithioglyoxal) by low temperature photolysis of 1,3-dithiol-2-one.^[6] Quantum chemical calculations reproduce the observed greater stability of 1,2-dithiete only if large basis-sets with polarization functions are used.^[7]

Structure of the dithiete S₂C₂(CO₂Me)₂. Selected distances and angles: r_C=C = 1.362, r_C-S = 1.738, r_S-S = 2.072 Å, <_S-S-C = 78.3°, <_S-C-S = 102°.^[4]

See also

• Dithietane - the corresponding saturated ring
• Thiete - an analogue with only one sulfur atom

Additional reading

• Diehl, F.; Meyer, H.; Schweig, A.; Hess, B. A.; Fabian, J. (September 1989). "1,2-Dithiete is more stable than 1,2-dithioglyoxal as evidenced by a combined experimental and theoretical IR spectroscopic approach". J. Am. Chem. Soc. 111 (19): 7651–7653. Bibcode:1989JAChS.111.7651D. doi:10.1021/ja00201a076.
• Vijay, D; Priyakumar, UD; Sastry, GN (2004). "Basis set and method dependence of the relative energies of C₂S₂H₂ isomers". Chemical Physics Letters. 383 (1–2): 192–197. Bibcode:2004CPL...383..192V. doi:10.1016/j.cplett.2003.11.021.
• Jonas, V; Frenking, G (1991). "On the crucial importance of polarization functions for the calculation of molecules with third-row elements: the conformations of chlorocarbonyl isocyanate ClC(O)NCO and the equilibrium of 1,2-dithioglyoxal with its cyclic isomer 1,2-dithiete". Chemical Physics Letters. 177 (2): 175–183. Bibcode:1991CPL...177..175J. doi:10.1016/0009-2614(91)90064-G.
• Gonzalez, L; Mo, O; Yanez, M (13 December 1996). "High-level ab initio calculations on the 1,2-dithioglyoxal/1,2-dithiete isomerism". Chemical Physics Letters. 263 (3): 407–413(7). Bibcode:1996CPL...263..407G. doi:10.1016/S0009-2614(96)01240-7.