Figure 4. Representative reductive cleavage, nucleophilic reactions and tandem processes for detection of small molecules.
a, Selective reduction of aromatic azides to anilines by hydrogen sulfide (H2S). b, A family of reaction-based dyes that all operate using the same general reaction-based switch as in part a. c, Detection of H2S by a tandem Michael addition. d, Dual nucleophilic addition strategy for H2S visualization. e, Thiol-mediated cleavage of electron-poor aryl sulfonates. f, Reversible sensing of thiols by disulfide–thiol exchange chemistry.