2,2'-Dithiobispyrazine: about the disulfide bond

Area of Science:

• Crystallography
• Quantum Chemistry
• Organic Chemistry

Background:

• Pyrazine-2-thiol is a heterocyclic compound.
• Disulfide compounds exhibit diverse molecular conformations.
• Understanding molecular structure influences chemical reactivity.

Purpose of the Study:

• To investigate the aerial oxidation product of pyrazine-2-thiol.
• To determine the molecular structure and conformation of 2,2 '-dithiobispyrazine.
• To explore the reactivity and stable rotamers of the disulfide.

Main Methods:

• X-ray diffraction for structural analysis.
• Cambridge Structural Database search for conformational comparison.
• Quantum theoretical studies for rotamer analysis and reaction mechanism investigation.

Main Results:

• Pyrazine-2-thiol condenses to form 2,2 '-dithiobispyrazine under aerial conditions.
• The molecule exhibits an almost perpendicular arrangement of pyrazine rings with a C-S-S-C torsion angle of -91.45 °.
• The lowest energy rotamer, observed in the crystalline state, is stabilized by various intermolecular interactions.
• Quantum chemical computations confirm the potential for S_N2 reactions.

Conclusions:

• The study elucidates the structure and conformational preferences of 2,2 '-dithiobispyrazine.
• The findings highlight the role of intermolecular interactions in stabilizing the observed crystal structure.
• 2,2 '-dithiobispyrazine is predicted to undergo reactions via the S_N2 mechanism.