Understanding Hydrogen Sulfide Storage: Probing Conditions for Sulfide Release from Hydrodisulfides

Hydrogen sulfide (H2S)
is an important biological signaling
agent that exerts action on numerous (patho)­physiological processes.
Once generated, H2S can be oxidized to generate reductant-labile
sulfane sulfur pools, which include hydrodisulfides/persulfides. Despite
the importance of hydrodisulfides in H2S storage and signaling,
little is known about the physical properties or chemical reactivity
of these compounds. We report here the synthesis, isolation, and characterization
(NMR, IR, Raman, HRMS, X-ray) of a small-molecule hydrodisulfide and
highlight its reactivity with reductants, nucleophiles, electrophiles,
acids, and bases. Our experimental results establish that hydrodisulfides
release H2S upon reduction and that deprotonation results
in disproportionation to the parent thiol and S0, thus
providing a mechanism for transsulfuration in the sulfane sulfur pool.