Redox-inactive ions control the redox-activity of molecular vanadium oxides

Polyoxometalates are key materials for energy conversion and storage due to their unique chemical tunability and electrochemical reactivity. Herein, we report that functionalization of molecular vanadium oxides, polyoxovanadates, with redox-inert Ca$^{2+}$ cations leads to a significant increase in their electron storage capabilities. The electrochemical performance of the Ca$^{2+}$-functionalized dodecavanadate [Ca$_{2}$V$_{12}$O$_{32}$Cl(DMF) $_{3}$]$^{2-}$ (={Ca$_{2}$V$_{12}$}) was thus compared with that of the precursor compound (H$_{2}$NMe$_{2}$)$_{2}$ [V$_{12}$O$_{32}$Cl] $^{3-}$ (={V$_{12}$}). {Ca$_{2}$V$_{12}$} can store up to five electrons per cluster, while {V12} only shows one reversible redox transition. In initial studies, we demonstrated that {Ca$_{2}$V$_{12}$} can be used as an active material in lithium-ion cathodes. Our results show how redox-inert cations can be used as structural and electrostatic stabilizers, leading to major changes in the redox-chemistry of polyoxovanadates

Selective Persulfide Detection Reveals Evolutionarily Conserved Antiaging Effects of S-Sulfhydration

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordData and Code Availability The raw data corresponding to the antibody microarray Detection of persulfidation of EGFR Pathway kinases represent entirely new application of the dimedone switch method and are therefore available in more detail from the corresponding author on request. Proteomic data used for Figure S2C are stored in Data S1 and S2 and for Figures S3H and S3I in Data S3 and S4. All in-gel persulfidation, as well as Western blot sufenylation and sulfynilation data are reported in main and supporting Figures. Other raw data are available at https://data.mendeley.com/datasets/pw2wz39tsk/2Life on Earth emerged in a hydrogen sulfide (H2S)-rich environment eons ago and with it protein persulfidation mediated by H2S evolved as a signaling mechanism. Protein persulfidation (S-sulfhydration) is a post-translational modification of reactive cysteine residues, which modulate protein structure and/or function. Persulfides are difficult to label and study due to their reactivity and similarity with cysteine. Here, we report a facile strategy for chemoselective persulfide bioconjugation using dimedone-based probes, to achieve highly selective, rapid, and robust persulfide labeling in biological samples with broad utility. Using this method, we show persulfidation is an evolutionarily conserved modification and waves of persulfidation are employed by cells to resolve sulfenylation and prevent irreversible cysteine overoxidation preserving protein function. We report an age-associated decline in persulfidation that is conserved across evolutionary boundaries. Accordingly, dietary or pharmacological interventions to increase persulfidation associate with increased longevity and improved capacity to cope with stress stimuli.IDEX BordeauxFRMMedical Research Council (MRC)Brian Ridge ScholarshipNorthcott Devon Medical Research FoundationMinistry of Education, Science and Technology Development of the Republic of SerbiaNIHDFG, GermanyAmerican Heart Association-Allen Initiative in Brain Health and Cognitive Impairmen

Dramatically Accelerated Selective Oxygen-Atom Transfer by a Nonheme Iron(IV)-Oxo Complex: Tuning of the First and Second Coordination Spheres

The new ligand N3Py(amide)SR and its Fe(II) complex [Fe(II)(N3Py(amide)SR)](BF4)2 (1) are described. Reaction of 1 with PhIO at -40 °C gives metastable [Fe(IV)(O)(N3Py(amide)SR)](2+) (2), containing a sulfide ligand and a single amide H-bond donor in proximity to the terminal oxo group. Direct evidence for H-bonding is seen in a structural analogue, [Fe(II)(Cl)(N3Py(amide)SR)](BF4)2 (3). Complex 2 exhibits rapid O-atom transfer (OAT) toward external sulfide substrates, but no intramolecular OAT. However, direct S-oxygenation does occur in the reaction of 1 with mCPBA, yielding sulfoxide-ligated [Fe(II)(N3Py(amide)S(O)R)](BF4)2 (4). Catalytic OAT with 1 was also observed