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Five-membered pyrroline nitroxides with high-potential is fascinating as catholyte for aqueous organic redox flow batteries (AORFBs), however, it suffers from a primary deficiency of insufficient stability due to ring-opening side reaction. Herein we report a spatial structure regulation strategy by host-guest chemistry, encapsulating 3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl (CPL) into hydrosoluble cyclodextrins (CDs) with an inclusion structure of N-O· head towards cavity bottom, to boost the solubility and cyclability of pyrroline nitroxides significantly. The armor-clad CPL (CPL⊂HP-β-CD) catholyte in 0.05-0.5 M presents a battery capacity fade rate as low as 0.002 %/cycle (0.233 %/day) compared to the sole CPL in 0.05 M (0.039 %/cycle or 5.23 %/day) over 500 cycles in assembled AORFBs. The optimized reclining spatial structure with N-O· head towards CD cavity bottom effectively inhibits the attack of Lewis base species on the hydrogen abstraction site in pyrroline ring, and thus avoids the ring-opening side reaction of pyrroline nitroxides. [ABSTRACT FROM AUTHOR]

We demonstrate that sequential disproportionation reactions can enable selective aggregation of two- or four electron–holes at a hypervalent iodine center. Disproportionation of an anodically generated iodanyl radical affords an iodosylbenzene derivative. Subsequent iodosylbenzene disproportionation can be triggered to provide access to an iodoxybenzene. These results demonstrate multielectron oxidation at the one-electron potential by selective and sequential disproportionation chemistry. [ABSTRACT FROM AUTHOR]

Oxygen minimum zones (OMZs), due to their large volumes of perennially deoxygenated waters, are critical regions for understanding how the interplay between anaerobic and aerobic nitrogen (N) cycling microbial pathways affects the marine N budget. Here we present a suite of measurements of the most significant OMZ N cycling rates, which all involve nitrite (NO2–) as a product, reactant, or intermediate, in the Eastern Tropical North Pacific (ETNP) OMZ. These measurements and comparisons to data from previously published OMZ cruises present additional evidence that NO3– reduction is the predominant OMZ N flux, followed by NO2– oxidation back to NO3–. The combined rates of both of these N recycling processes were observed to be much greater (up to nearly 200x) than the combined rates of the N loss processes of anammox and denitrification, especially in waters near the anoxic / oxic interface. We also show that NO2– oxidation can occur in functionally anoxic incubations, measurements that further strengthen the case for truly anaerobic NO2– oxidation. We also evaluate the possibility that NO2– dismutation provides the oxidative power for anaerobic NO2– oxidation. Although almost all treatments returned little evidence for dismutation (as based on product inhibition, substrate stimulation, and stoichiometric hypotheses), results from one treatment under conditions closest to in situ NO2– values may support the occurrence of NO2– dismutation. The partitioning of N loss between anammox and denitrification differed widely from stoichiometric predictions of at most 29 % anammox; in fact, N loss rates at many depths consisted entirely of anammox. Through investigating the magnitudes of NO3– reduction and NO2– oxidation, testing for anaerobic NO2– oxidation, examining the possibility of NO2– dismutation, and further documenting the balance of N loss processes, these new data shed light on many open questions in OMZ N cycling research. [ABSTRACT FROM AUTHOR]

[Display omitted] • The stannate salts are versatile precursors to explore hydrolysis chemistry and dismutation reactions. • Tetra(aqua) diorganotin dications are stabilized as multicomponent molecular crystals. • Structural chemistry reveals the role of alkanesulfonates as both coordinating and non-coordinating ligands. The reactions between diphenyl/di- n -butyltin oxide, dialkyl sulfite, and tetra- n -butylammonium iodide (120 °C, 20 h) proceed via isomerization of the sulfite to sulfonate anion and afford the stannate salts, [ n -Bu 4 N][Ph 2 Sn(OSO 2 Et) 3 ] (1) and [ n -Bu 4 N][ n -Bu 2 Sn(OSO 2 n -Pr) 3 ] (2). The solutions of 1 and 2 in acetonitrile upon exposure to atmospheric conditions resulted in the isolation of multicomponent molecular crystals, [Ph 2 Sn(H 2 O) 4 ][ n -Bu 4 N] 3 [OSO 2 Et] 5 ·3H 2 O (3), [ n -Bu 2 Sn(H 2 O) 4 ][ n -Bu 4 N] 2 [OSO 2 n -Pr] 4 ·H 2 O (4) and [ n -Bu 2 Sn(μ -OH)(H 2 O) 2 ] 2 [ n - Bu 4 N ] 2 [ OSO 2 n - Pr ] 4 (5). In the solid state, the diorganotin cations in 3 – 5 owe their stability to O H---O hydrogen bonds with non-coordinating sulfonate anions. Reactions of the previously reported stannate salt, [ n -Bu 4 N][Ph 2 Sn(OSO 2 Me) 3 ] (6) with N -donor ligands provide a manifestation of phenyl group dismutation to afford new coordination assemblies, [Ph 3 Sn(OSO 2 Me)H 2 O][4,4′-bipy] (7) and [Ph 3 Sn(OSO 2 Me)] (8). X-ray crystallographic studies reveal affinity of the alkanesulfonates to function in both primary and secondary coordination sphere that enables the formation of anionic, cationic, and neutral organotin frameworks. [ABSTRACT FROM AUTHOR]