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1. Di(indenyl)beryllium

   https://doi.org/10.1002/anie.202107980  

   Koby, Ross_F; Schley, Nathan_D; Hanusa, Timothy_P (August 2021, Angewandte Chemie International Edition)

   Abstract The bonding in beryllocene, [BeCp₂], took decades to establish, owing to its unexpected mixed hapticity structure (i.e., [Be(η⁵‐Cp)(η¹‐Cp)]). Beryllium complexes containing the indenyl ligand, which is a close relative of the cyclopentadienyl anion, but which is also known to exhibit its own bonding peculiarities (e.g., facile η⁵⇄ η³shifts), have remained unknown. Standard metathetical approaches to their synthesis (e.g., with K[Ind′] + BeX₂in an ether solvent) give rise to intractable oils from which nothing identifiable can be isolated. In contrast, mechanochemical preparation, involving the solvent‐free grinding of BeBr₂and potassium indenides, leads to the production of discrete (indenyl)beryllium complexes, including [Be(C₉H₇)₂] (1) and [Be{1,3‐(SiMe₃)₂C₉H₅}Br] (2). The former displays η⁵/η¹‐coordinated ligands in the solid state, but DFT calculations indicate that an η⁵/η⁵‐conformation is less than 5 kcal mol⁻¹higher in energy. 

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2. Ni ₂ P‐Modified Ta ₃ N ₅ and TaON for Photocatalytic Nitrate Reduction

   https://doi.org/10.1002/cnma.202000174  

   Wei, Lin; Adamson, Marquix_A_S; Vela, Javier (May 2020, ChemNanoMat)

   Abstract Self‐sustaining photocatalytic NO₃⁻reduction systems could become ideal NO₃⁻removal methods. Developing an efficient, highly active photocatalyst is the key to the photocatalytic reduction of NO₃⁻. In this work, we present the synthesis of Ni₂P‐modified Ta₃N₅(Ni₂P/Ta₃N₅), TaON (Ni₂P/TaON), and TiO₂(Ni₂P/TiO₂). Starting with a 2 mM (28 g/mL NO₃⁻−N) aqueous solution of NO₃⁻, as made Ni₂P/Ta₃N₅and Ni₂P/TaON display as high as 79% and 61% NO₃⁻conversion under 419 nm light within 12 h, which correspond to reaction rates per gram of 196 μmol g⁻¹ h⁻¹and 153 μmol g⁻¹ h⁻¹, respectively, and apparent quantum yields of 3–4%. Compared to 24% NO₃⁻conversion in Ni₂P/TiO₂, Ni₂P/Ta₃N₅and Ni₂P/TaON exhibit higher activities due to the visible light active semiconductor (SC) substrates Ta₃N₅and TaON. We also discuss two possible electron migration pathways in Ni₂P/semiconductor heterostructures. Our experimental results suggest one dominant electron migration pathway in these materials, namely: Photo‐generated electrons migrate from the semiconductor to co‐catalyst Ni₂P, and upshift its Fermi level. The higher Fermi level provides greater driving force and allows NO₃⁻reduction to occur on the Ni₂P surface. 

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3. Structural insights into supramolecular interactions in isostructural salts of 2,4,6-triaminopyrimidinium with various heterocyclic carboxylates

   https://doi.org/10.1107/S2053229624008787  

   Mohana, Marimuthu; Gomathi, Sundaramoorthy; Thomas_Muthiah, Packianathan; Butcher, Ray J (November 2024, Acta Crystallographica Section C Structural Chemistry)

   2,4,6-Triaminopyrimidine is an interesting and challenging molecule due to the presence of multiple hydrogen-bond donors and acceptors. Its noncovalent interactions with a variety of carboxylic acids provide several supramolecular aggregates with frequently occurring molecular synthons. The present work focuses on the supramolecular interactions of 2,4,6-triaminopyrimidinium 3-(indol-3-yl)propionate–3-(indol-3-yl)propionic acid (1/1), C₄H₈N₅⁺·C₁₁H₁₀NO₂⁻·C₁₁H₁₁NO₂, (I), 2,4,6-triaminopyrimidinium 2-(indol-3-yl)acetate, C₄H₈N₅⁺·C₁₀H₈NO₂⁻, (II), 2,4,6-triaminopyrimidinium 5-bromothiophene-2-carboxylate, C₄H₈N₅⁺·C₅H₂BrO₂S⁻, (III), and 2,4,6-triaminopyrimidinium 5-chlorothiophene-2-carboxylate, C₄H₈N₅⁺·C₅H₂ClO₂S⁻, (IV). All four salts exhibit robust homomeric and heteromericR₂²(8) ring motifs. Salts (I) and (II) develop sextuple [in (I)] and quadruple [in (I) and (II)] hydrogen-bonded arrays through fused-ring motifs. Salt (II) exhibits a rosette-like architecture. Salt (IV) is isostructural and isomorphous with salt (III), exhibiting an identical crystal structure with a different composition and an identical supramolecular architecture. In salts (III) and (IV), a linear hetero-tetrameric motif is formed and, in addition, both salts exhibit halogen–π interactions which enhance the crystal stability. All four salts develop a supramolecular hydrogen-bonded pattern facilitated by several N—H...O and N—H...N hydrogen bonds with multiple furcated donors and acceptors. 

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4. A highly stable and conductive cerium‐doped Li ₇ P ₃ S ₁₁ glass‐ceramic electrolyte for solid‐state lithium–sulfur batteries

   https://doi.org/10.1111/jace.19712  

   Mirtaleb, Amirhossein; Wang, Ruigang (February 2024, Journal of the American Ceramic Society)

   Abstract In this report, a facile wet chemical method using acetonitrile combined with thermal annealing was used to prepare Li₂S‐P₂S₅(LPS) based glass‐ceramic electrolytes with (1 wt%, 3 wt%, and 5 wt% Ce₂S₃) and without Ce₂S₃doping. The crystal structure, ionic conductivity, and chemical stability of Li₇P₃S₁₁glass‐ceramic electrolytes were examined at varying temperatures (250–350°C). The results indicated that the highest ionic conductivity of 3.15 × 10⁻⁴S cm⁻¹for pure Li₇P₃S₁₁was observed at a temperature of 325°C. By incorporating 1 wt% Ce₂S₃and subjecting it to a heat treatment at 250°C, the glass ceramic electrolyte attained a remarkable ionic conductivity of 7.7 × 10⁻⁴(S cm⁻¹) at 25°C. Furthermore, it exhibited a stable and extensive electrochemical potential range, reaching up to 5 volts when compared to the Li/Li⁺reference electrode. By tuning the glass transition and crystallization temperature, cerium doping seems to make Li₇P₃S₁₁more chemically stable, compared to its original 70Li₂S‐30P₂S₅counterpart. According to Raman and X‐ray photoelectron spectroscopy analyses, cerium doping inhibits the decomposition of highly conductive P₂S₇^4‐(pyro‐thiophosphate) to PS₄³⁻and P₂S₆⁴⁻. Doped LPS has a greater crystallinity and more uniform microstructure than pure LPS, according to XRD, Raman spectroscopy, and scanning electron microscopy analysis. Consequently, Li₇P_2.9Ce_0.1S₁₁electrolyte shows great potential as a solid‐state electrolyte for constructing high‐performance sulfide‐based all‐solid‐state batteries. 

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5. Nitrate Loads From Land to Stream Are Balanced by In‐Stream Nitrate Uptake Across Seasons in a Dryland Stream Network

   https://doi.org/10.1029/2024JG008117  

   Handler, Amalia_M; Helton, Ashley_M; Grimm, Nancy_B (November 2024, Journal of Geophysical Research: Biogeosciences)

   Abstract Exploring nitrogen dynamics in stream networks is critical for understanding how these systems attenuate nutrient pollution while maintaining ecological productivity. We investigated Oak Creek, a dryland watershed in central Arizona, USA, to elucidate the relationship between terrestrial nitrate (NO₃⁻) loading and stream NO₃⁻uptake, highlighting the influence of land cover and hydrologic connectivity. We conducted four seasonal synoptic sampling campaigns along the 167‐km network combined with stream NO₃⁻uptake experiments (in 370–710‐m reaches) and integrated the data in a mass‐balance model to scale in‐stream uptake and estimate NO₃⁻loading from landscape to the stream network. Stream NO₃⁻concentrations were low throughout the watershed (<5–236 μg N/L) and stream NO₃⁻vertical uptake velocity was high (5.5–18.0 mm/min). During the summer dry (June), summer wet (September), and winter dry (November) seasons, the lower mainstem exhibited higher lateral NO₃⁻loading (10–51 kg N km⁻² d⁻¹) than the headwaters and tributaries (<0.001–0.086 kg N km⁻² d⁻¹), likely owing to differences in irrigation infrastructure and near‐stream land cover. In contrast, during the winter wet season (February) lateral NO₃⁻loads were higher in the intermittent headwaters and tributaries (0.008–0.479 kg N km⁻² d⁻¹), which had flowing surface water only in this season. Despite high lateral NO₃⁻loading in some locations, in‐stream uptake removed >81% of NO₃⁻before reaching the watershed outlet. Our findings highlight that high rates of in‐stream uptake maintain low nitrogen export at the network scale, even with high fluxes from the landscape and seasonal variation in hydrologic connectivity. 

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