Colorimetric Carbonyl Sulfide (COS)/Hydrogen Sulfide (H 2 S) Donation from γ-Ketothiocarbamate Donor Motifs.

Hydrogen sulfide (H ₂ S) is a biologically active molecule that exhibits protective effects in a variety of physiological and pathological processes. Although several H ₂ S-related biological effects have been discovered by using H ₂ S donors, knowing how much H ₂ S has been released from donors under different conditions remains challenging. Now, a series of γ-ketothiocarbamate (γ-KetoTCM) compounds that provide the first examples of colorimetric H ₂ S donors and enable direct quantification of H ₂ S release, were reported. These compounds are activated through a pH-dependent deprotonation/β-elimination sequence to release carbonyl sulfide (COS), which is quickly converted into H ₂ S by carbonic anhydrase. The p-nitroaniline released upon donor activation provides an optical readout that correlates directly to COS/H ₂ S release, thus enabling colorimetric measurement of H ₂ S donation.
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