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1. The redox code of plants

   https://doi.org/10.1111/pce.14787  

   Mittler, Ron; Jones, Dean P. (December 2023, Plant, Cell & Environment)

   Abstract Central metabolism is organised through high‐flux, Nicotinamide Adenine Dinucleotide (NAD⁺/NADH) and NADP⁺/NADPH systems operating at near equilibrium. As oxygen is indispensable for aerobic organisms, these systems are also linked to the levels of reactive oxygen species, such as H₂O₂, and through H₂O₂to the regulation of macromolecular structures and activities, via kinetically controlled sulphur switches in the redox proteome. Dynamic changes in H₂O₂production, scavenging and transport, associated with development, growth and responses to the environment are, therefore, linked to the redox state of the cell and regulate cellular function. These basic principles form the ‘redox code’ of cells and were first defined by D. P. Jones and H. Sies in 2015. Here, we apply these principles to plants in which recent studies have shown that they can also explain cell‐to‐cell and even plant‐to‐plant signalling processes. The redox code is, therefore, an integral part of biological systems and can be used to explain multiple processes in plants at the subcellular, cellular, tissue, whole organism and perhaps even community and ecosystem levels. As the environmental conditions on our planet are worsening due to global warming, climate change and increased pollution levels, new studies are needed applying the redox code of plants to these changes. 

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2. Effect of iron redox ratio on the structures of boroaluminosilicate glasses

   https://doi.org/10.1111/jace.18685  

   Tuheen, Manzila I.; Sun, Wei; Du, Jincheng (August 2022, Journal of the American Ceramic Society)

   Abstract Iron oxide is commonly found in natural or industrial glass compositions and can exist as ferrous (Fe²⁺) or ferric (Fe³⁺) species, with their ratios depending on glass composition, temperature, pressure and the redox reactions during the glass forming process. The iron redox ratio plays an important role on silicate glass structures and consequently various properties. This work aims to study the effect of iron oxide, and particularly the iron redox ratio, on the structures of borosilicate and boroaluminosilicate glasses using molecular dynamics simulations with newly developed iron potential parameters that are compatible with the borosilicate potentials. The results provide detailed cation coordination states of both iron species and the effect of redox ratio on boron coordination and other structural features. Particularly, competition for charge compensating modifier cations (such as Na⁺) among the fourfold‐coordinated cations such as B³⁺, Al³⁺, and Fe³⁺is investigated by calculating the cation–cation pair distribution functions and coordination preferential ratios. The results show that the trivalent ferric ions, with a shorter Fe–O bond distance and better defined first coordiation shell with mainly four‐fold coordination, act as a glass former whereas the divalent ferrous ions mainly play the role of glass modifier. The ferrous/ferric ratio (Fe²⁺/Fe³⁺) was found to affect the glass chemistry and hence glass properties by regulating the amount of four‐coordinated boron, the fraction of non‐briding oxygen and other features. The results are compared with available experimental data to gain insights of the complex structures and charge compensation schemes of the glass system. 

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3. Redox‐Neutral TEMPO Catalysis: Direct Radical (Hetero)Aryl C−H Di‐ and Trifluoromethoxylation

   https://doi.org/10.1002/anie.202009490  

   Lee, Johnny W.; Lim, Sanghyun; Maienshein, Daniel N.; Liu, Peng; Ngai, Ming‐Yu (September 2020, Angewandte Chemie International Edition)

   Abstract Applications of TEMPO^.catalysis for the development of redox‐neutral transformations are rare. Reported here is the first TEMPO^.‐catalyzed, redox‐neutral C−H di‐ and trifluoromethoxylation of (hetero)arenes. The reaction exhibits a broad substrate scope, has high functional‐group tolerance, and can be employed for the late‐stage functionalization of complex druglike molecules. Kinetic measurements, isolation and resubjection of catalytic intermediates, UV/Vis studies, and DFT calculations support the proposed oxidative TEMPO^./TEMPO⁺redox catalytic cycle. Mechanistic studies also suggest that Li₂CO₃plays an important role in preventing catalyst deactivation. These findings will provide new insights into the design and development of novel reactions through redox‐neutral TEMPO^.catalysis. 

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4. Uranium Redox and Deposition Transitions Embedded in Deep‐Time Geochemical Models and Mineral Chemistry Networks

   https://doi.org/10.1029/2023GC011267  

   Moore, E_K; Li, J.; Zhang, A.; Hao, J.; Morrison, S_M; Hummer, D_R; Yee, N. (February 2024, Geochemistry, Geophysics, Geosystems)

   Abstract Uranium (U) is an important global energy resource and a redox sensitive trace element that reflects changing environmental conditions and geochemical cycling. The redox evolution of U mineral chemistry can be interrogated to understand the formation and distribution of U deposits and the redox processes involved in U geochemistry throughout Earth history. In this study, geochemical modeling using thermodynamic data, and mineral chemistry network analysis are used to investigate U geochemistry and deposition through time. The number of U⁶⁺mineral localities surpasses the number of U⁴⁺mineral localities in the Paleoproterozoic. Moreover, the number of sedimentary U⁶⁺mineral localities increases earlier in the Phanerozoic than the number of U⁴⁺sedimentary mineral localities, likely due to the necessity of sufficient sedimentary organic matter to reduce U⁶⁺–U⁴⁺. Indeed, modeling calculations indicate that increased oxidative weathering due to surface oxygenation limited U⁴⁺uraninite (UO₂) formation from weathered granite and basalt. Louvain network community detection shows that U⁶⁺forms minerals with many more shared elements and redox states than U⁴⁺. The range of weighted Mineral Element Electronegativity Coefficient of Variation (wMEE_CV) values of U⁶⁺minerals increases through time, particularly during the Phanerozoic. Conversely, the range of wMEE_CVvalues of U⁴⁺minerals is consistent through time due to the relative abundance of uraninite, coffinite, and brannerite. The late oxidation and formation of U⁶⁺minerals compared to S⁶⁺minerals illustrates the importance of the development of land plants, organic matter deposition, and redox‐controlled U deposition from ground water in continental sediments during this time‐period. 

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5. Homoleptic complexes of isocyano- and diisocyanobiazulenes with a 12-electron, ligand-based redox capacity

   https://doi.org/10.1039/D3DT01958F  

   Connelly, Patrick T.; Applegate, Jason C.; Maldonado, David A.; Okeowo, Monisola K.; Henke, Wade C.; Oliver, Allen G.; Berrie, Cindy L.; Barybin, Mikhail V. (July 2023, Dalton Transactions)

   The redox non-innocent 2-isocyano-6,6′-biazulenic ligand platform exhibits reduction potential inversion and offers construction of molecular organometallic electron reservoirs with 2e⁻-per-ligand reversible redox capacity. 

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