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Extracellular histones in neutrophil extracellular traps (NETs) or in chromatin from injured tissues are highly pathological, particularly when liberated by DNases. We report the development of small polyanions (SPAs) (~0.9–1.4 kDa) that interact electrostatically with histones, neutralizing their pathological effects. In vitro, SPAs inhibited the cytotoxic, platelet-activating and erythrocyte-damaging effects of histones, mechanistic studies revealing that SPAs block disruption of lipid-bilayers by histones. In vivo, SPAs significantly inhibited sepsis, deep-vein thrombosis, and cardiac and tissue-flap models of ischemia-reperfusion injury (IRI), but appeared to differ in their capacity to neutralize NET-bound versus free histones. Analysis of sera from sepsis and cardiac IRI patients supported these differential findings. Further investigations revealed this effect was likely due to the ability of certain SPAs to displace histones from NETs, thus destabilising the structure. Finally, based on our work, a non-toxic SPA that inhibits both NET-bound and free histone mediated pathologies was identified for clinical development. Histones, proteins that bind DNA, are toxic for pathogens outside cells but can also cause multi-organ damage as seen in sepsis. Here the authors develop small negatively charged molecules that can be used as histone antidotes, and show that they improve the phenotype in mouse models with histone-related pathologies. [ABSTRACT FROM AUTHOR]

The 48‐FeIII‐containing 96‐tungsto‐16‐phosphate, [FeIII48(OH)76(H2O)16(HP2W12O48)8]36− (Fe48), has been synthesized and structurally characterized. This polyanion comprises eight equivalent {FeIII6P2W12} units that are linked in an end‐on fashion forming a macrocyclic assembly that contains more iron centers than any other polyoxometalate (POM) known to date. The novel Fe48 was synthesized by a simple one‐pot reaction of an {Fe22} coordination complex with the hexalacunary {P2W12} POM precursor in water. The title polyanion was characterized by single‐crystal XRD, FTIR, TGA, magnetic and electrochemical studies. [ABSTRACT FROM AUTHOR]

Cost, safety, and cycle life have emerged as prime concerns to build robust batteries to cater to the global energy demand. These concerns are impacted by all battery components, but the realizable energy density of lithium‐ion batteries (LIBs) is limited by the performance of cathodes. Thus, cathode materials have a significant role to play in advancing the performance and economics of secondary batteries. To realize next generation Li‐ion and post Li‐ion batteries, a variety of cathode insertion materials have been explored, but finding a cost effective and stable cathode material that can deliver high energy density has been a daunting task. Oxide cathode materials are ubiquitous in commercial applications, as they can deliver high capacity. In comparison, polyanionic insertion materials can offer tuneable (high) redox potential, operational safety, and structural as well as thermal stability. Indeed, a wide range of polyanionic materials like phosphates, borates, sulfates, and their complexes have been reported. In this article, the alkali metal fluorophosphates class of polyanionic cathodes for secondary batteries is discussed. The various reported fluorophosphate insertion materials are discussed in terms of their electrochemical and electrocatalytic properties. The historical overview, recent progress, and remaining challenges for polyanionic fluorophosphates are presented along with suggested future research directions and potential application. [ABSTRACT FROM AUTHOR]

Three inorganic-organic hybrid nanoclusters of copper and cobalt containing arsenotungstates with lone pair on heteroatom have been synthesized under mild reactions conditions. All the compounds have been characterized by single crystal X-ray diffraction, Fourier transform infrared, UV/visible spectroscopy, thermogravimetric and field emission scanning electron microscopic (FE-SEM) analysis. The compound [NaRb{Cu(phen) (H2O)2Cl}2][{Cu(phen)(H2O)}2{Cu(phen)(H2O)Cl}2{Cu2As2W19O67(H2O)] (1a) is a sandwiched type arsenotungstate with two copper atoms in square planar environment in the belt region. The polyanion-1 is decorated by four copper phenanthroline complexes through a terminal oxygen atom of the polyanion. In addition, two other cobalt containing inorganic-organic hybrid lone pair containing arsenotungstates(III) with 1,10-phenanthroline [NaRbCo(phen)3][{Co(phen)(H2O)3}CoAs2W20O67(H2O)3] (2a) and 2,2'-bipyridine[Na3RbCo(2,2-bipy)3][CoAs2W20O67(H2O)3] (3a) has also been synthesized under mild conditions. The polyanion (2) is a mono cobalt substituted sandwiched type structure that is decorated by a cobalt phenanthroline complex attached to the polyanion through a terminal oxygen atom. Meanwhile the other complex (3) is also a monocobalt substituted sandwiched type structure which contains a cobalt 2,2'-bipyridine complex in the cationic part. Polyanion-1 shows intermolecular p-p stacking interaction between the phenanthroline ligand in the cationic part and one that is attached directly to the polyanion. The compounds are also characterized by FE-SEM analysis and the compound 3a shows ultra- smooth cuboids with grain size in the range of 1 to several micrometer though some very small irregular particles with the size of a few micrometer were also observed. [ABSTRACT FROM AUTHOR]

Uranium(IV) oxide clusters, colloids, and materials are designed and studied for 1) nuclear materials applications, 2) understanding the environmental fate and transport of actinides, and 3) exploring the complex bonding behavior of open‐shell f‐elements. UIV‐oxyhydroxsulfate clusters are particularly relevant in industrial processes and in nature. Recent studies have shown that counter‐cations to these polynuclear anions differentiate rich structural topologies in the solid‐state. Herein, we present nine different structures with wheel‐shaped [U70(OH)36(O)64(SO4)60]4− (U70) linked into one‐ and two‐dimensional frameworks with sulfate, divalent transition metals (CrII, FeII, CoII, NiII) and UV. Small‐angle X‐ray scattering of these phases dissolved in butylamine reveals differing supramolecular assembly of U70 clusters, controlled primarily by sulfates. However, observed trends in transition metal linking guide future design of U70 materials with different topologies. Finally, U70 linking via UIV‐O‐UV‐O‐UIV bridges presents a rare example of mixed‐oxidation‐state uranium oxides without disorder. [ABSTRACT FROM AUTHOR]

Layered nickel‐rich transition metal oxide has been receiving much attention as high‐energy‐density cathode materials for rechargeable lithium‐ion batteries. However, the severe capacity fading caused by bulk structural degradation of Ni‐rich cathodes during lithiation/delithiation obstructs their commercialization. Herein, we modify the LiNi0.92Co0.06Al0.02O2 (NCA92) cathode materials by W6+ cation and BO33− polyanion co‐doping to improve the structural stability and upgrade the electrochemical reversibility. The co‐doped NCA92 materials show remarkably improved cycling stability at 1 C with a capacity retention of 93.4 % after 100 cycles, whereas the pristine cathodes exhibit poor capacity retention of 53.0 % and suffer severe structural deterioration. Further studies reveal that the particle fragmentation resulted from the inherent internal strain and the structural degradation upon cycling can be effectively mitigated by W6+ cation and BO33− polyanion co‐doping. Besides, W6+ and BO33− co‐doping could enlarge the interlayer spacing of NCA92, thus increasing lithium‐ion diffusion coefficient, which is conducive to enhancing the rate capability. The present work demonstrates that cationic‐anionic co‐doping is an effective strategy to maintain the structural stability of Ni‐rich cathode materials, and it promotes the development of stable cathode materials for high energy density lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries are receiving increasing attention; however, the development of high‐voltage cathodes is limited by the narrow voltage window of conventional aqueous electrolytes. Herein, it is reported that Na3V2(PO4)2O1.6F1.4 exhibits the excellent performance, optimal to date, among polyanion cathode materials in a novel neutral water‐in‐bisalts electrolyte of 25 m ZnCl2 + 5 m NH4Cl. It delivers a reversible capacity of 155 mAh g−1 at 50 mA g−1, a high average operating potential of ≈1.46 V, and stable cyclability of 7000 cycles at 2 A g−1. [ABSTRACT FROM AUTHOR]

A [Ag (bipy)2]+ modified butterfly-like hybrid network stabilized by [AlW12O40]5- polyoxoanions, formulated as [Ag(bipy)2]8[{Ag(bipy)}{AlW12O40}]2 (1) (bipy = 2,2'-bipyridine), has been synthesized hydrothermally and characterized by IR, XRD, TG, UV and single crystal X-ray diffraction. In 1, two [{Ag(bipy)}{AlW12O40}]4− polyanions form transverse units/longitudinal units through π-π stacking. The transverse units connect two adjacent longitudinal units by [Ag(bipy)2]+ to form a butterfly-like 1 D chain structure. Adjacent butterfly chains form a two-dimensional planar structure similar to the copper-like arrangement through supramolecular interactions of [AlW12O40]5− and [Ag(bipy)2]+. Further extension of the 2 D copper-like layers through supramolecular interaction gives a 3 D network. Compound 1 exhibits good charge transfer ability (Rct = 7.8Ω) and excellent electrocatalytic activity for H2O2 reduction. Compound 1 shows efficient degradation of RhB under ultraviolet light. [ABSTRACT FROM AUTHOR]

Polyelectrolyte microcapsules (PEMCs) have biocompatible microcompartments. Therefore, PEMCs are useful for applications in cosmetics, food, pharmaceutics, and other industries. The fabrication of PEMCs often involves the use of harsh chemicals or cytotoxic organic phases that make biomedical applications of the microcapsules challenging. In this report, we present an all-aqueous droplet microfluidics platform for the generation of magnetic PEMCs. In the platform, we use an aqueous-two-phase system (ATPS) of polyethylene glycol (PEG) and dextran (Dex), to generate water-in-water droplets, which are magnetically functionalized with ferrofluid. Strong polyelectrolytes (PEs) with opposite charges are used in each ATPS phase. We make emulsion templates of magnetic Dex, containing the polycations, in a continuous phase of PEG. We then apply a magnetic field to move the magnetic droplets to a second PEG phase, which contains the polyanions. By careful tuning of the fluxes of the two PEs in their respective phases, we trigger the formation of a shell at the droplet interface. Owing to the presence of the ferrofluid, the resulting microcapsules are magnetically responsive. We show that the magnetic PEMCs are capable of passive release of large pseudo-drugs as well as triggered release using external stimuli such as osmotic shock and pH change. We expect that magnetic PEMCs from this biocompatible all-aqueous platform will find utility in the fabrication of functionalized drug carriers for targeted drug delivery. [ABSTRACT FROM AUTHOR]

Polyanion‐type sodium (Na) vanadium phosphate in the form of Na3V2(PO4)3 has demonstrated reasonably high capacity, good rate capability, and excellent cyclability. Two of three Na ions per formula can be deintercalated at a potential 3.4 V versus Na+/Na with oxidation of V3+/4+. In the reversible process, two Na ions intercalate back resulting in a discharge capacity of 117.6 mAh g−1. Further intercalation is possible but at a low potential of 1.4 V versus Na+/Na accompanied by vanadium reduction V3+/2+, leading to a capacity of 60 mAh g−1. Due to its marvelous electrochemical performance, it has attracted a lot of attention since its discovery in the 1990s. To develop truly useable polyanion‐type vanadium phosphate, better understanding of its crystal configuration, sodium ions' transportation, and electronic structure is essential. Therefore, this review only focuses on the inside of crystal configuration and electronic structure of polyanion‐type vanadium phosphate, Na3V2(PO4)3, since there are a few good reviews on various processing technologies. [ABSTRACT FROM AUTHOR]

Factor H exists as a 155,000 dalton, extended protein composed of twenty small domains which is flexible enough that it folds back on itself. Factor H regulates complement activation through its interactions with C3b and polyanions. Three binding sites for C3b and multiple polyanion binding sites have been identified on Factor H. In intact Factor H these sites appear to act synergistically making their individual contributions difficult to distinguish. Recombinantly expressed fragments of human Factor H were examined using surface plasmon resonance (SPR) for interactions with C3, C3b, iC3b, C3c, and C3d. Eleven recombinant proteins of lengths from one to twenty domains were used to show that the three C3b-binding sites exhibit 100-fold different affinities for C3b. The N-terminal site [complement control protein (CCP) domains 1-6] bound C3b with a K d of 0.08 μM and this interaction was not influenced by the presence or absence of domains 7 and 8. Full length Factor H similarly exhibited a K d for C3b of 0.1 μM. Unexpectedly, the N-terminal site (CCP 1-6) bound native C3 with a K d of 0.4 μM. The C-terminal domains (CCP 19-20) exhibited a K d of 1.7 μM for C3b. We localized a weak third C3b binding site in the CCP 13-15 region with a K d estimated to be ~15 μM. The C-terminal site (CCP 19-20) bound C3b, iC3b, and C3d equally well with a K d of 1 to 2 μM. In order to identify and compare regions of Factor H that interact with polyanions a family of 18 overlapping three domain recombinant proteins spanning the entire length of Factor H were expressed and purified. Immobilized heparin was used as a model polyanion and SPR confirmed the presence of heparin binding sites in CCP 6-8 (K d 1.2 μM) and in CCP 19-20 (4.9 μM) and suggested the existence of a weak third polyanion binding site in the center of Factor H (CCP 11-13). Our results unveil the relative contributions of different regions of Factor H to its regulation of complement, and may contribute to the understanding of how defects in certain Factor H domains lead to disease. [ABSTRACT FROM AUTHOR]

Titanium‐based polyanions have been intensively investigated for sodium‐ion batteries owing to their superior structural stability and thermal safety. However, their low working potential hindered further applications. Now, a cation and anion dual doping strategy is used to boost the redox potential of Ti‐based cathodes of Na3Ti0.5V0.5(PO3)3N as a new cathode material for sodium ion batteries. Both the Ti3+/Ti4+ and V3+/V4+ redox couples are reversibly accessed, leading to two distinctive voltage platforms at ca. 3.3 V and ca. 3.8 V, respectively. The remarkably improved cycling stability (86.3 %, 3000 cycles) can be ascribed to the near‐zero volume strain in this unusual cubic symmetry, which has been demonstrated by in situ synchrotron‐based X‐ray diffraction. First‐principles calculations reveal its well‐interconnected 3D Na diffusion pathways with low energy barriers, and the two‐sodium‐extracted intermediate NaTi0.5V0.5(PO3)3N is also a stable phase according to formation energy calculations. [ABSTRACT FROM AUTHOR]

The development of high energy/power density sodium‐ion batteries (SIBs) is still challenged by the high redox potential of Na/Na+ and large radius of Na+ ions, thus requiring extensive further improvement to, in particular, enhance the capacity and voltage of cathode materials. Among the various types of cathodes, the polyanion cathodes have emerged as the most pragmatic option due to their outstanding thermostability, unique inductive effect, and flexible structures. In this Review, a critical overview of the design principles and engineering strategies of polyanion cathodes that could have a pivotal role in developing high energy/power density SIBs are presented. Specifically, the engineering of polyanion cathode materials for higher voltage and specific capacity to increase energy density is discussed. The way in which morphology control, architectural design, and electrode processing have been developed to increase power density for SIBs is also analyzed. Finally, the remaining challenges and the future research direction of this field are presented. [ABSTRACT FROM AUTHOR]

Oxygen-anion redox in lithium-rich layered oxides can boost the capacity of lithium-ion battery cathodes. However, the over-oxidation of oxygen at highly charged states aggravates irreversible structure changes and deteriorates cycle performance. Here, we investigate the mechanism of surface degradation caused by oxygen oxidation and the kinetics of surface reconstruction. Considering Li2MnO3, we show through density functional theory calculations that a high energy orbital (lO2p') at under-coordinated surface oxygen prefers over-oxidation over bulk oxygen, and that surface oxygen release is then kinetically favored during charging. We use a simple strategy of turning under-coordinated surface oxygen into polyanionic (SO4)2−, and show that these groups stabilize the surface of Li2MnO3 by depressing gas release and side reactions with the electrolyte. Experimental validation on Li1.2Ni0.2Mn0.6O2 shows that sulfur deposition enhances stability of the cathode with 99.0% capacity remaining (194 mA h g−1) after 100 cycles at 1 C. Our work reveals a promising surface treatment to address the instability of highly charged layered cathode materials. Oxygen-anion redox in lithium-rich layered oxides can boost the capacity of lithium-ion battery cathodes. Here, the authors investigate the mechanism of surface degradation caused by oxygen oxidation and the kinetics of surface reconstruction. [ABSTRACT FROM AUTHOR]

Various cathode materials have been proposed for high‐performance rechargeable batteries. Vanadyl phosphate is an important member of the polyanion cathode family. VOPO4 has seven known crystal polymorphs with tunneled or layered frameworks, which allow facile cation (de)intercalations. Two‐electron transfer per formula unit can be realized by using VV/VIV and VIV/VIII redox couples. The electrochemical performance is closely related to the structures of VOPO4 and the types of inserted cations. This Review outlines the crystal structures of VOPO4 polymorphs and their lithiated phases. The research progress of vanadyl phosphate cathode materials for different energy storage systems, including lithium‐ion batteries, sodium‐ion batteries, potassium‐ion batteries, multivalent batteries, and supercapacitors, as well as the related mechanism investigations are summarized. It is hoped that this Review will help with future directions of using vanadyl phosphate materials for energy storage. [ABSTRACT FROM AUTHOR]

Polyelectrolyte complexes formed from nucleic acids and synthetic polycations are studied because of their potential in gene delivery. Coarse‐grained molecular dynamics simulations are performed to examine the impact of chain length and polyanion stiffness on polyplex formation and aggregation. Polyplexes containing single polyanion chain fall into three structural regimes depending on polyanion stiffness: flexible polyanions form collapsed complexes, semiflexible polyanions form various morphologies including toroids and hairpins, and stiff polyanions form rod‐like structures. Polyplex size generally decreases as polycation length increases. Polyelectrolyte complexes aggregate in some simulations containing multiple polyanions and an excess of short polycations. Aggregation is observed to only occur for semiflexible and stiff polyanions and is promoted by shorter polycation lengths. Simulations of short, stiff polyanions condensed by long polycations are used as a model for siRNA gene delivery complexes. These simulations show multiple polyanions are spaced out along the polycation with polyanion–polyanion interactions, usually limited to overlapping chain ends. These structures differ from aggregates of longer polyanions in which the polyanions are packed together in parallel, forming bundles. [ABSTRACT FROM AUTHOR]

ε-[Al13O4(OH)24(H2O)12]7+, which shares similarity with the phosphotriesterase active site ZnII–OH–ZnII, was specially chosen to interact with the cluster α-PMo10V2O405− to form a new three-dimensional intercluster, which crystallized in the monoclinic space group P21/m with Z = 2, for the decontamination of chemical warfare agents. The experimental results showed that 50 mg of the compound decontaminated 96.4% (within 120 min) and 99.5% (within 40 min) of sulfur mustard (HD) (4 μL) and soman (GD) (4 μL), respectively, in ambient conditions. The decontamination processes followed first-order reaction kinetics with a rate constant and half-life of 0.01234 min−1 and 56.15 min for HD and 0.1198 min−1 and 5.78 min for GD, respectively. It was concluded that the α-PMo10V2O405− moiety was responsible for the catalytic oxidation of HD into non-toxic sulfoxide, while the ε-[Al13O4(OH)24(H2O)12]7+ moiety was responsible for the catalytic hydrolysis of HD and GD into nontoxic hydrolysates. Besides, the compound showed notable efficacy for the decontamination of HD on guinea pig skin and of GD on Kunming mouse skin, indicating high potential for use in human skin protection and treatment. [ABSTRACT FROM AUTHOR]

Many gaps in our understanding of Alzheimer's disease remain despite intense research efforts. One such prominent gap is the mechanism of Tau condensation and fibrillization. One viewpoint is that positively charged Tau is condensed by cytosolic polyanions. However, this hypothesis is likely based on an overestimation of the abundance and stability of cytosolic polyanions and an underestimation of crucial intracellular constituents – the cationic polyamines. Here, we propose an alternative mechanism grounded in cellular biology. We describe extensive molecular dynamics simulations and analysis on physiologically relevant model systems, which suggest that it is not positively charged, unmodified Tau that is condensed by cytosolic polyanions but negatively charged, hyperphosphorylated Tau that is condensed by cytosolic polycations. Our work has broad implications for anti-Alzheimer's research and drug development and the broader field of tauopathies in general, potentially paving the way to future etiologic therapies. [ABSTRACT FROM AUTHOR]

Oil/water separation has recently attracted a great deal of attention for research due to the frequent occurrence of an oil spill as well as the increase of industrial and household oily wastewater. Therefore, the purpose of this study is to demonstrate underwater superoleophobic crosslinked phosphorylated poly(vinyl alcohol) hydrogel coated stainless steel mesh (CL-PPVA@SSM), which was fabricated using a simple dip-coating method and aldol reaction on the mesh substrate. The as-prepared CL-PPVA@SSM is capable of separating oil from a variety of different oil/water mixtures with high separation efficiency up to 99.2%, excellent recyclability and fast water permeate flux of 467.7 L m–2 h–1, which makes it suitable for the separation of oil-water mixtures from oil-water emulsions. Also, in the oil-water separation process, the CL-PPVA@SSM is capable to remove organic dye from the water. The CL-PPVA@SSM exhibits stability under various harsh conditions such as mechanical abrasion. Importantly, the CL-PPVA@SSM shows a massive potential to separate kitchen waste oil/water mixtures due to the underwater superoleophobic property as required for the recycling of kitchen waste oil. Therefore, this method has been met with a promising application prospect of practical application. [ABSTRACT FROM AUTHOR]

The present work aimed to remove a toxic organic dye using a recyclable Dawson-type heteropolyanion as a green catalyst. Indeed, a novel molybdenum-substituted heteropolyanion HP2W15Mo3Co2.5O62·20H2O was synthesized and characterized by EDX, IR, 31P-NMR and cyclic voltammetry methods. Thereafter, the synthesized catalyst was used in the oxidation reaction of fuchsine acid (FA) by H2O2. As a result, the catalyst exhibited high catalytic activity in the degradation of FA at natural pH and room temperature. The catalytic oxidation efficiency as 97.97% was found after 120 min under catalyst mass of 0.001 g and H2O2 concentration of 49 µM. By combining the used process with UV radiation at 365 nm, the FA oxidation time becomes three times lower than that seen in the presence of H2O2 only. Moreover, ·OH involvement in dye degradation was confirmed and the H2O2 activation mechanism using HP2W15Mo3Co2.5O62·20H2O as catalyst was proposed. The stability of the recovered catalyst of the FA degradation has been confirmed by IR spectroscopy. Therefore, this study can provide an efficient green way of using cobalt catalyst for environmental remediation. [ABSTRACT FROM AUTHOR]

Polymers bearing quaternized 4-vinylpyridine (QVP) groups are known for their antibacterial activities and these polymers can form polyelectrolyte complexes (PEC) with polyanions through electrostatic interactions. PEC formation can be used to adjust the antibacterial activity of polymers of QVP, deliver active molecules, or design antibacterial supramolecular structures. However, the antibacterial activity of PECs of QVP polymers has not been investigated. In this study, a copolymer of QVP was mixed with polyacrylic acid in various molar ratios of components to form PECs. Hydrodynamic diameters and zeta potentials of formed PECs were determined by dynamic and electrophoretic light scattering spectroscopy techniques. The zeta potentials of PECs changed between -24 and +16 mV with variation in the ratio of components. Antibacterial assays against E. coli revealed a relation of PEC formation with antibacterial activity since MIC values changed between 125-1000 µg/mL according to the ratio of components. [ABSTRACT FROM AUTHOR]

The design of biologically active dosage forms based on chitosan is significantly limited by its insolubility at pH values above 6.0–6.5 and worsening of its gastrointestinal absorption capacity upon transition to neutral and alkaline environmental conditions. The partial acylation of short-chain chitosans with the use of betaine in the presence of a coupling reagent (betaination) allows one to synthesize noncytotoxic derivatives soluble in an alkaline medium and preserving a high antibacterial activity in weakly alkaline physiological media, which makes them promising for application in pharmaceutical compositions. This study addresses the formation of polyelectrolyte complexes of partially betainated short-chain chitosans with different chain length and degree of betaination with a weak polyacid in acidic and weakly alkaline media. As a polyanion, a regularly alternating copolymer of maleic acid and N-vinylpyrrolidone is used, one of the advantages of which is its ability to be involved in chemical modification with various ligands, including biologically active ones. It is shown that soluble polyelectrolyte complexes can be formed by the direct mixing of components in a weakly alkaline medium (pH 7.4). The range of solubility of the complexes ([polycation] : [polyanion]) in a weakly alkaline medium is wider than that in an acidic one. Nonstoichiometric soluble polyelectrolyte complexes are also prepared using partially betainated chitosans as lyophilizing polyelectrolytes. The structure of soluble polyelectrolyte complexes of various compositions is investigated by static and dynamic light scattering as well as electrophoretic light scattering. The data obtained suggest that, both in the acidic and weakly alkaline medium, the polyelectrolyte complexes occur as polymolecular particles with either negative or positive surface charge. The results of this study can be used for designing new biocompatible and biodegradable delivery systems for biologically active compounds and genetic material. [ABSTRACT FROM AUTHOR]

Structural details of thermoresponsive, cationically poly(N-iso-propylacrylamide-co-methacrylamido propyl trimethyl ammonium chloride) microgels and the influence of the anionic electrolyte polystyrene sulfonate (PSS) on the internal structure and dynamics of the cationic microgels have been studied with a combination of small angle neutron scattering (SANS) and neutron spin echo (NSE) spectroscopy. While SANS can yield information on the overall size of the particles and on the typical correlation length inside the particles, studying the segmental polymer dynamics with NSE gives access to more internal details, which only appear due to their effect on the polymer motion. The segmental dynamics of the microgels studied in this paper is to a large extent suppressed by the PSS additive. Possible scenarios of the influence of the polyanions on the microgel structure and dynamics are discussed. [ABSTRACT FROM AUTHOR]

Solid-state materials containing rotatable polyanions, such as B12 H 12 2 − , constitute a peculiar class of ionic conductors due to their unique transport behavior, where rotating polyanions promote phase transitions to disordered phases with several orders of magnitude enhancement in cation conductivities. A major drawback is the high temperature required to activate rotation and thereby low conductivities at room temperature. Here, we elucidate a mechanism to drastically reduce the temperature based on the use of pseudorotation in high-H coordination hydride complexes. We demonstrate this mechanism for an existing complex transition metal hydride Li5MoH11 containing MoH 9 3 − , and we present a strong potential of this material to unprecedentedly exhibit a high lithium ion conductivity of 7.9 × 10–2 S cm−1 at room temperature. [ABSTRACT FROM AUTHOR]

New polyoxometalate (POM) H4Li6[β-P2CoW17O62]·x:H2O (1) is synthesized for the first time. The structure of 1 consists of Wells-Dawson type [β-P2CoW17O62]6− POM connected through [Li6(H2O)6]6+ clusters giving rise to a linear chain. The chemical composition of the newly synthesized polyanion is confirmed via1H, 13C, and 31P NMR, FTIR, UV-Vis, and SEM-EDX as well as magnetic measurements. [ABSTRACT FROM AUTHOR]

The first alkali‐metal vanadium iodate fluoride, CsVO2F(IO3), with a novel 3D anionic framework, has been rationally designed and hydrothermally synthesized. The 3D [VO2F(IO3)]− framework in CsVO2F(IO3) is built from 0D Λ‐shaped cis‐[VO3F(IO3)2]4− polyanions via corner‐sharing of oxo anions and bridging of the iodate groups. CsVO2F(IO3) displays both a strong second‐harmonic generation (SHG) 1.1 times as strong as KTiOPO4 (KTP) under 2.05 μm laser radiation and high laser‐induced damage threshold (LIDT) of 107.9 MW cm−2. This work provides a new route to design SHG crystals with stable 3D anionic structures from low‐dimensional structural building units. [ABSTRACT FROM AUTHOR]

The human tau is a microtubule-associated intrinsically unstructured protein that forms intraneuronal cytotoxic deposits in neurodegenerative diseases, like tauopathies. Recent studies indicate that in Alzheimer's disease, ribosomal dysfunction might be a crucial event in the disease pathology. Our earlier studies had demonstrated that amorphous protein aggregation in the presence of ribosome can lead to sequestration of the ribosomal components. The present study aims at determining the effect of incubation of the full-length tau protein (Ht40) and its microtubule binding 4-repeat domain (K18) on the eukaryotic ribosome. Our in vitro studies show that incubation of Ht40 and the K18 tau variants with isolated non-translating yeast ribosome can induce a loss of ribosome physical integrity resulting in formation of tau-rRNA-ribosomal protein aggregates. Incubation with the tau protein variants also led to a disappearance of the peak indicating the ribosome profile of the HeLa cell lysate and suppression of translation in the human in vitro translation system. The incubation of tau protein with the ribosomal RNA leads to the formation of tau-rRNA aggregates. The effect of K18 on the yeast ribosome can be mitigated in the presence of cellular polyanions like heparin and tRNA, thereby indicating the electrostatic nature of the aggregation process. [ABSTRACT FROM AUTHOR]

Two ruthenium-containing polyoxometalate-based hybrids (Ru-POMs), KH8[Ru3O(Trz)6Cl3]2[(NaO6)W6(H2O)6(AsW9O33)4]·28H2O (1) and H3[Ru3O(Trz)6Cl3]2[(WO)2W(OH)(AsW9O33)2]·6H2O (2), (Trz = 1,2,4-triazole), were successfully isolated by a one-step hydrothermal method under different acidic conditions and further characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), IR spectroscopy, electrospray ionization and mass spectrometry (ESI-MS), thermogravimetric (TG) analyses and elemental analyses. Single-crystal X-ray diffraction analyses reveal two polyanions comprised of four/two identical trivacant Keggin-type polyanion building blocks, leading to the formation of tetrameric/dimeric assembly stabilized by additional metal–oxo cores, respectively. ESI-MS shows that the polyanion units [(NaO6)W6(H2O)6(AsW9O33)4]11− and [(WO)2W(OH)(AsW9O33)2]5− are intact in mixed solvent. Moreover, the two heterogeneous catalysts with trinuclear ruthenium cations were further investigated, and 1 was found to exhibit much higher yield (94.1%)/conversion (95.1%) and better selectivity (>99%) towards the oxidation of thioanisole to sulfoxide than 2. [ABSTRACT FROM AUTHOR]

In this work, the preparation of conducting polymer‐based composites using a biological anionic polymer based on salmon deoxyribonucleic acid (DNA) is presented. The most commonly used polymers poly(3,4‐ethylenedioxythiophene) (PEDOT), as well as polypyrrole, are polymerized in the presence of DNA. Since conjugated polymers are in the polycationic state in their electrically conducting form, the role of the counterion is now fulfilled by the low cost biomolecule DNA as an alternative material, which is also a polyanion thanks to its phosphate chain. The resulting synthesized material is a conducting polymer–DNA biocomposite. Such materials are highly attractive for the rising field of bioelectronics and biosensors, especially in organic electrochemical transistors (OECTs) and ion pumps. OECTs made of these conducting polymer biocomposites are fabricated and their electrochemical device operation is compared to the most widely used PEDOT:polystyrenesulfonate. [ABSTRACT FROM AUTHOR]

In this paper, highly efficient mixed polyanion NaFe1−x(VO)xPO4 series of glass-ceramic cathode samples have been synthesized for use in sodium-ion batteries with good specific capacity and capacity retention. Electrochemical experiments show that the best-conducting NaFe0.5(VO)0.5PO4 (x = 0.5 mol%) glass-ceramic sample delivers the highest capacity for both the 1st and 20th cycles since it exhibits two distinct voltage plateaus (3.2 V and 2.8 V, respectively) together with a discharge capacity retention (69.66%) even at 10C compared with all the other investigated samples. These desirable results related to electrochemical performance make the mixed polyanion NaFe1−x(VO)xPO4 series of glass-ceramic cathode networks suitable for large-scale economic sodium-ion battery applications. [ABSTRACT FROM AUTHOR]

EuPtSn2 was obtained by melting of the elements in a sealed tantalum ampoule followed by an annealing sequence for crystal growth. The EuPtSn2 sample was studied through its Guinier powder pattern and the structure was refined from single‐crystal X‐ray diffractometer data: CeRhSn2 type, Cmcm, a = 472.05(3), b = 1724.19(12), c = 957.36(7) pm, wR2 = 0.0388, 879 F2 values and 30 variables. The platinum and tin atoms build up a three‐dimensional [PtSn2]2– polyanionic network which consists of distorted PtSn5 square pyramids (265–278 pm Pt–Sn) and Sn2 dumbbells with 281 and 299 pm Sn–Sn distances. The structural relationship with DyRhGe2 and Ce3Pt4Ge6 is discussed. EuPtSn2 shows Curie–Weiss behavior with an experimental magnetic moment of 7.78(1) μB / Eu, indicating stable divalent europium. This is corroborated by 151Eu Mössbauer spectroscopy. Antiferromagnetic ordering is detected below 3.4 K. Specific heat measurements confirm the magnetic ordering and indicate a second phase transition through a clear λ‐type signal at 7.3 K which might be associated with a structural distortion. [ABSTRACT FROM AUTHOR]

Polyphosphate (PolyP) is one of the most compact inorganic polyanionic biopolymers that participates in various physiological processes. However, the mechanism of the interaction between polyP and proteins remains poorly understood. Herein, we report that polyP can interact with positively charged green fluorescent protein, +36GFP, resulting in liquid–liquid phase separation (LLPS) by intermolecular electrostatic interactions in cells. Upon nutrient deprivation, genetically engineered Citrobacter freundii accumulates intracellular polyP at a rate of 210 μm min−1, resulting in the compartmentation of +36GFP at the cell poles within 1 h. Medium chain‐length polyP (60‐mer) could induce the formation of +36GFP coacervates in vitro at a protein concentration as low as 200 nm, which is of the same magnitude as native proteins. In contrast, shorter polyP (14‐mer) could not induce LLPS under the same conditions. This may offer a general approach to manipulate protein–protein interactions through LLPS. [ABSTRACT FROM AUTHOR]

The expansion of metal–organic frameworks (MOFs) into new proton-conducting platforms has aroused special interest due to their defined frameworks coupled with chemically adjustable porosities. Immobilizing polyoxometalates (POMs) into MOFs can adequately intensify the superiorities of the POM guest and MOF matrix in the proton conducting field; however, vanadium-substituted POMs as guests in MOFs for conductivity have attracted limited attention compared to the parent Keggin polyanions. Herein, a series of molybdovanadophosphoric acids (denoted PMoVx) are impregnated into the MIL-101 framework to obtain PMoVx@MIL-101 composites for proton conduction. The effects of proton number and POM loading amounts on the conductive behaviour of POM@MOF composites have been documented. Additionally, the composites are incorporated into polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) blends to fabricate hybrid membranes. Preferable proton conductivities are achieved with PMoV2@MIL-101-11.2 (6.31 × 10−3 S cm−1) along with its hybrid membrane (1.96 × 10−3 S cm−1) at ∼98% RH and 353 K; these values are about two orders of magnitude higher than those of the parent MIL-101. This work contributes to driving further advances of polyoxometalate-based MOF composites in similar electrochemical apparatus. [ABSTRACT FROM AUTHOR]

A sample inorganic A-type Anderson polyoxometalate (POM) (TeMo6) compound formulated as [Co(H2O)6]3[TeMo6O24] is synthesized in aqueous solution by slow evaporation technique. Single-crystal X-ray diffraction analysis reveals that the obtained compound crystallizes in the centrosymmetric hexagonal space group (R-3c) with a formula unit made up of one [TeMo6O24]6− A-type Anderson anion and three [Co(H2O)3]2+ cations. The molecular Hirshfeld surface indicates that the crystal packing is stabilized by H-bonds interactions to generate 3D supramolecular frameworks. Furthermore, some optical properties such as bandgap energy, refractive index, dielectric constant and optical conductivity of the sample are investigated. The large value of refractive index known in the visible region of electromagnetic spectrum (n = 3.5 at 1.8 eV) reveals that this sample can become a promising candidate for visible optical communication devices. The emission fluorescent spectrum in the solid state at room temperature is measured and the decay lifetime curves are obtained by monitoring the ligand-to-metal charge transfer transition (LMCT). The studies of the colorimetric properties of the sample reveal that the color coordinates (x = 0.33667; y = 0.25564) are located in the region of National Television System Committee (NTSC) in the CIE chromaticity chart and the calculated correlated color temperature value (CCT ~ 5085 K) indicates that the optimized compound could be applied as a cool light emission diode. [ABSTRACT FROM AUTHOR]

Two Ni/Co-substituted sandwich-type germanomolybdates, {[M3(NH2-trz)6(H2O)6][M4(H2O)2(HGeMo10O36)2]}·nH2O (M = Ni2+ (1) and Co2+ (2), n = 10 (1) or 11 (2), NH2-trz = 4-amino-1,2,4-triazole), have been obtained under hydrothermal conditions. 1 and 2 represent the first trivacant Keggin germanomolybdates involving unprecedented [α-GeMo10O36]8− fragments and {M3O4} quasi-cubane building units. Both of them exhibit electrocatalytic behaviours for H2O2 reduction and photocatalytic properties for CO2 conversion. [ABSTRACT FROM AUTHOR]

Four hetero-polyoxometalate compounds were obtained in aqueous solutions, following the synthetic combination of Na9[B-α-AsIIIW9O33] with the 4f tetravalent cerium cation in the presence of the formate ligand at different pH values (ranging from 1.5 to 6). All four molecules [{Ce6(μ3-O)4(μ3-OH)4(HCOO)3,5}4(AsIIIW9O33)4]2− compound 1, [(Ce6(μ3-O)4(μ3-OH)4)(H2O)4(AsIIIW9O33)(HCOO)9]6− compound 2, [(Ce6(μ4-O)3(μ3-O)5 (μ2-H2O)3)(HCOO)3(AsVW9O34)3]22− compound 3, and [(W4O10){(Ce6(μ3-O)5(μ4-O)3(μ2-H2O))(AsVW9O34)3}2]44− compound 4 were constructed around one to four hexanuclear cerium clusters of [Ce6O8] type. For the compounds 1–3, the arsenato-polytungstate POM units and formate ligands were associated and participated in the stabilization of one cerium(IV)-bearing hexanuclear unit in a cyclic motif (1), a monomeric POM species for 2, and a trimeric POM species for 3. However, in the last molecular system (4), only inorganic entities were bonded to the hexameric cerium(IV) clusters. From the structural point of view, compound 4 appeared as the association of two compound 3 entities, in which the formate ligands were replaced by an inorganic tungsten-based sub-unit coming from the partial decomposition of the {AsIIIW9O33} precursor. The behavior and the association modes of the four molecular species were explained on the basis of the pH variation used in their syntheses. All four compounds were characterized by single-crystal X-ray diffraction, IR spectroscopy, TGA, SEM/EDX microscopy, and ICP analyses. The solution behavior was assessed on compound 3 by using small angle X-ray scattering (SAXS) measurements. [ABSTRACT FROM AUTHOR]

The Na superionic conductor of (NASICON)-type Na 4 VMn(PO 4) 3 (NVMP) with a three-dimensional framework and high operating voltage has been extensively investigated for sodium-ion batteries (SIBs). However, unexpected Jahn-Teller effect and sluggish Na+ diffusion kinetics inevitably lead to rapid capacity fade and unfavorable structural distortion. Herein, the double-pinning effect of Al/F co-doping was adopted for the NVMP system to enhance structural stability and facilitate Na+ diffusion. The as-synthesized NVMP-Al&F presents a highly reversible capacity of 110 mAh g−1 at 0.1 C, accompanied with a long-term lifespan of 1000 cycles at 5 C (capacity retention of 86.1 %). Moreover, in situ X-ray diffraction affirms the reversible structural evolution and small volume variation (∼4.43 %) during the highly reversible sodiation/desodiation processes. Benefiting from the double-pinning effect, the lowered Na+ migration barrier effectively facilitates Na+ diffusion and increases to higher reversible capacity by combining theoretical calculation and kinetic analysis. The assembled NVMP-Al&F//hard carbon (HC) full cell manifests a high energy density of 353.9 Wh kg−1 and excellent cycling durability of 91.3 % at 1 C after 100 cycles. This work sheds light on the double-pinning as a novel strategy to boost the cycling stability of high-performance NASICON-type cathodes. [Display omitted] • The double-pinning effect in Na 4 VMn(PO 4) 3 with superior structural and electrochemical stabilization was proposed. • The introduction of Al and F ions in Na 4 VMn(PO 4) 3 exhibits rapid Na+ diffusion kinetics and increased capacitance behavior. • The optimized Mn-O bond achieves excellent structural stability by collaborative regulation of electronic structure. • The Na-ion full cell shows high energy density of 353.9 Wh kg−1 with a capacity retention of 91.3 % at 1 C after 100 cycles. [ABSTRACT FROM AUTHOR]

Transient interactions between the anaphase-promoting complex/cyclosome (APC/C) and its activator subunit Cdc20 or Cdh1 generate oscillations in ubiquitylation activity necessary to maintain the order of cell cycle events. Activator binds the APC/C with high affinity and exhibits negligible dissociation kinetics in vitro, and it is not clear how the rapid turnover of APC/C-activator complexes is achieved in vivo. Here, we describe a mechanism that controls APC/C-activator interactions based on the availability of substrates. We find that APC/C-activator dissociation is stimulated by abundant cellular polyanions such as nucleic acids and polyphosphate. Polyanions also interfere with substrate ubiquitylation. However, engagement with high-affinity substrate blocks the inhibitory effects of polyanions on activator binding and APC/C activity. We propose that this mechanism amplifies the effects of substrate affinity on APC/C function, stimulating processive ubiquitylation of high-affinity substrates and suppressing ubiquitylation of low-affinity substrates. Activation of APC/C depends on transient interactions with an activator subunit. Here, the authors show that cellular polyanions trigger APC/C-activator dissociation and that high-affinity substrates block this effect, suggesting that substrate availability controls APC/C-activator binding. [ABSTRACT FROM AUTHOR]

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We studied the complex between ovalbumin and long flexible poly-(sodium 4-styrene sulfonate) as a function of pH and temperature. We used various techniques [turbidimetry, conductometry, dynamic light scattering, viscosimetry, and ultra-small-angle light scattering (USALS)] to fully characterize the coacervate complex. Different phases of complexation versus temperature were determined by turbidimetric analysis (pHc, pHϕ1, and pHϕ2). The optimal protein/polyelectrolyte interaction occurred at pHopt 4. An increase in temperature made the hydrophobic interactions more favorable in the case of the soluble complex and complex coacervation phases (pH > pHϕ2). We systematically determined the activation energy to follow the conformational changes of the complex at different temperatures. At pHopt, the size of the formed complex showed a remarkable decrease with temperature increase. USALS was used to determine simultaneously the radius of gyration (Rg) and fractal dimension Df of the coacervate. [ABSTRACT FROM AUTHOR]

The combination of hexacyanoferrate anions with protonated N,N′-dipyridyl-naphthalene diimide tectons resulted in a novel cuboid 3-D H-bonded anion-coordinated framework. Induced by anion–π interactions, such a unique framework is further catenated into an unprecedented five-fold interpenetrated D–A hybrid heterostructure with 1-D hexacyanoferrate polyanions and naphthalene diimide aggregates as electron donors and acceptors, respectively. The photophysical and photochemical properties have also been discussed. [ABSTRACT FROM AUTHOR]

An isopolyanion {W4O16} within an archetypal {P8W48} heteropolyanion assembly [(P8W48O184)(W4O16)K10Li4Mn10Na(H2O)50Cl2]15− (Mn10W4-P8W48) has been synthesized by the reaction of the cyclic superlacunary anion [H7P8W48O184]33− and Mn(ClO4)2·6H2O in 1 M LiCl solution medium at pH 8. The isolated compound has been characterized by single-crystal X-ray crystallography, powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy, elemental analysis and thermogravimetric analysis. Electrochemical studies were also performed on Mn10W4-P8W48, which confirmed the presence of Mn centres bonded to the tungstic framework. The novel polyanion [(P8W48O184)(W4O16)K10Li4Mn10Na(H2O)50Cl2]15− is the first example of a macrocyclic complex, where an isopolyanion (W4O16)8− is embedded within the inner cavity of {P8W48} and is placed in position by six MnII cations as anchors, whereas the exocyclic coordination of four further MnII cations to {P8W48} yields an extended structure by linking neighbouring polyanions through {W–O–Mn–O–W} bridges. Furthermore, the polyanion Mn10W4-P8W48 is the first derivative of {P8W48} with six MnII ions (largest) coordinated to the inner side of the crown ring as anchors. [ABSTRACT FROM AUTHOR]

VOPO4⋅x H2O has been proposed as a cathode for rechargeable aqueous zinc batteries. However, it undergoes significant voltage decay in conventional Zn(OTf)2 electrolyte. Investigations show the decomposition of VOPO4⋅x H2O into VOx in the electrolyte and voltage drops after losing the inductive effect from polyanions.PO43− was thus added to shift the decomposition equilibrium. A high concentration of cheap, highly soluble ZnCl2 salt in the electrolyte further prevents VOPO4⋅x H2O dissolution. The cathode shows stable capacity and voltage retentions in 13 m ZnCl2/0.8 m H3PO4 aqueous electrolyte, in direct contrast to that in Zn(OTf)2 where the decomposition product VOx provides most electrochemical activity over cycling. Sequential H+ and Zn2+ intercalations into the structure are revealed, delivering a high capacity (170 mAh g−1). This work shows the potential issue with polyanion cathodes in zinc batteries and proposes an effective solution using fundamental chemical principles. [ABSTRACT FROM AUTHOR]

Interpolyelectrolyte complexes possess high ion-exchange capacity, which makes it possible to obtain metal-polymer compounds on their basis and allows their use for the extraction of metal ions from dilute aqueous solutions. The deposition and reduction of metal ions is the main method of obtaining nanoparticles in polymer matrices. Tuning the interaction of functional groups of polyanions and polycations with ions/metal surfaces provides wide opportunities to control the structure and size of nanoparticles and to obtain nanocomposites. The review discusses the work of A.B. Zezin devoted to the structure and mechanisms of the formation of metal-polymer complexes in films and coatings of interpolyelectrolyte complexes, which were the starting point for the development of methods for producing nanocomposites. [ABSTRACT FROM AUTHOR]

Orthophosphoric acid solutions of sodium orthovanadate, sodium tungstate, and sodium molybdate are tested as potential corrosion inhibitors of the Al2Cu intermetallic phase. Corrosion inhibition is observed for 0.2 M solutions of Na3VO4 and Na2WO4 by increasing the pH to > 2. When the pH is < 2, the aforementioned salts increase the corrosion rate of the intermetallic phase. A 0.2 M solution of Na3VO4 causes the precipitation of vanadium phosphate on the surface of the Al2Cu phase at pH = 1. [ABSTRACT FROM AUTHOR]

The new intermetallic compound Ba6Pt22Al53 was obtained from reaction of the elements. The title compound crystallizes in the hexagonal crystal system with lattice parameters of a = 1427.5(3) and c = 1614.3(4) pm and space group P63/mcm (Z = 2) and adopts a new structure type (Pearson code hP162, Wyckoff sequence l2k3j2i2hg2ecb). In the structure, the Pt and Al atoms form a complex polyanionic [Pt22Al53]δ− network, while the Ba cations reside in cavities. The structure can be described as a packing of layers, formed by the Pt@Aln polyhedra parallel to (001). The layers are stacked in an ABCB fashion. Within the [Pt22Al53] framework, one of the shortest Pt–Al distances (239 pm) reported is found, suggesting extremely strong covalent bonding interactions. Due to slightly enhanced displacement parameters of the Al9 site, temperature dependent single-crystal X-ray diffraction (285 and 90 K) and low-temperature heat capacity experiments were conducted. However, no structural phase transition was observed down to 2 K. With the help of DFT calculations, the bonding situation was elucidated in detail, verifying the strong heteroatomic bonding and the destabilization of the structure upon in silico distortions. Mulliken charge calculations confirm the picture of the polyanionic framework and cationic Ba atoms within the cavities. [ABSTRACT FROM AUTHOR]