Transformations of sulfane sulfur compounds (e. g. organic polysulfides (R−Sn−R, n>2) and elemental sulfur (S8)) play pivotal roles in the biochemical landscape of sulfur, and thus supports signaling activities of H2S. Although a number of previous reports illustrate amine mediated reactions of S8 and thiol (RSH) yielding R−Sn−R, this report illustrates that a tripodal [ZnII] complex [(Bn3Tren)ZnII−OH2](ClO4)2 (1) facilitates the reactions of sulfane sulfur and thiol (RSH), thereby offering an amine‐free biologically relevant complementary route. UV‐vis monitoring of the reactions and a set of control experiments underline the definitive role of [ZnII] coordination motif in the reactions of sulfane sulfur (e. g. S8 and R−Sn−R) with RSH. Detailed investigations (UV‐vis, NMR, ESI‐MS, intermediate trapping, and TEMPO radical interference experiments) disclose the key differences in the [ZnII] versus previously known amine mediated routes. Moreover, the persulfide (RSS−) trapping experiments using 1‐fluoro‐2,4‐dinitrobenzene (F‐DNB) reveal the intermediacy of RSS− species in the [ZnII] mediated reactions of sulfane sulfur and thiol, thereby demonstrating [ZnII] assisted persulfidation of thiol in the presence of sulfane sulfur species. Of broader impact, this study underscores the feasible influence of biologically relevant [ZnII] coordination motifs (e. g. carbonic anhydrase) on the sulfane sulfur chemistry in biology.

Transformations of nitrogen‐oxyanions (NOx−) to ammonia impart pivotal roles in sustainable biogeochemical processes. While metal‐mediated reductions of NOx− are relatively well known, this report illustrates proton‐assisted transformations of NOx− anions in the presence of electron‐rich aromatics such as 1,3,5‐trimethoxybenzene (TMB−H, 1 a) leading to the formation of diaryl oxoammonium salt [(TMB)2N+=O][NO3−] (2 a) via the intermediacy of nitrosonium cation (NO+). Detailed characterizations including UV/Vis, multinuclear NMR, FT‐IR, HRMS, X‐ray analyses on a set of closely related metastable diaryl oxoammonium [Ar2N+=O] species disclose unambiguous structural and spectroscopic signatures. Oxoammonium salt 2 a exhibits 2 e− oxidative reactivity in the presence of oxidizable substrates such as benzylamine, thiol, and ferrocene. Intriguingly, reaction of 2 a with water affords ammonia. Perhaps of broader significance, this work reveals a new metal‐free route germane to the conversion of NOx to NH3.

Transformations of nitrogen‐oxyanions (NOx−) to ammonia impart pivotal roles in sustainable biogeochemical processes. While metal‐mediated reductions of NOx− are relatively well known, this report illustrates proton‐assisted transformations of NOx− anions in the presence of electron‐rich aromatics such as 1,3,5‐trimethoxybenzene (TMB−H, 1 a) leading to the formation of diaryl oxoammonium salt [(TMB)2N+=O][NO3−] (2 a) via the intermediacy of nitrosonium cation (NO+). Detailed characterizations including UV/Vis, multinuclear NMR, FT‐IR, HRMS, X‐ray analyses on a set of closely related metastable diaryl oxoammonium [Ar2N+=O] species disclose unambiguous structural and spectroscopic signatures. Oxoammonium salt 2 a exhibits 2 e− oxidative reactivity in the presence of oxidizable substrates such as benzylamine, thiol, and ferrocene. Intriguingly, reaction of 2 a with water affords ammonia. Perhaps of broader significance, this work reveals a new metal‐free route germane to the conversion of NOx to NH3.