Figure 2.

SNO⁻ is the reaction product of HS⁻ with nitrosopersulfide. (a) Overlayed ¹⁵N NMR spectra of PNP⁺SS¹⁵NO⁻ (100 mM in acetone, black line) as well as of a mixture of PNP⁺SS¹⁵NO⁻ (30 mM) and H₂S (50 mM) in a solution of acetone : water 9 : 1, recorded 1 h after mixing (red line). While we ascribe the signal at 354 ppm to SS¹⁵NO⁻, the newly appearing signal at 314 ppm in the nitrosopersulfide/hydrogen sulfide mixture is assigned to S¹⁵NO⁻ (figure 4b). (b) Identification of HSNO as a reaction product of PNP⁺SSNO⁻ with H₂S. 250 µM PNP⁺SSNO⁻ was mixed with an equimolar amount of H₂S (solution in THF) and reaction monitored in positive mode. Simulated mass spectra for some of the species identified during the measurement are shown in black. (c) Negative ion mode ionization of a reaction mixture containing 250 µM PNP⁺SS¹⁵NO⁻ and H₂S. Recorded spectrum is shown in red, and simulated mass spectra of S¹⁵NO⁻ and are shown in blue and green, respectively.