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A novel modified polyoxometalate, {PMo12O40[Cu(2,2′‐bpy)]}[Cu(2,2′‐bpy)(en)(H2O)]2 [2,2′‐bpy is 2,2′‐bipyridyl (C10H8N2) and en is ethylenediamine (C2H8N2)], has been synthesized hydrothermally and structurally characterized by elemental analysis, TG, IR, XPS and single‐crystal X‐ray diffraction. The structural analysis reveals that the compound contains the reduced Keggin polyanion [PMo12O40]6− as the parent unit, which is monocapped by [Cu(2,2′‐bpy)]2+ fragments via four bridging O atoms on an {Mo4O4} pit and bi‐supported by two [Cu(2,2′‐bpy)(en)(H2O)]2+ coordination cations simultaneously. There exist strong intramolecular π–π stacking between the capping and supporting units, which play a stabilizing role during the crystallization of the compound. Adjacent POM clusters are further aggregated to form a three‐dimensional supramolecular network through noncovalent forces, hydrogen bonding and π–π stacking interactions. In addition, the photocatalytic properties were investigated in detail, and the results indicated that the compound can be used as a photocatalyst towards the decomposition of the organic pollutant methylene blue (MB). [ABSTRACT FROM AUTHOR]

Newfangled frangipani-like [MV5O6(μ3-O)5(SO4)(COO)5] (M = Nb/W) polyanions served as 5-connected molecular building blocks (MBBs) that simultaneously assembled with 4-connected [V5O9Cl] MBBs and tricarboxylate ligands (H3BTC) to form two new polyoxovanadate-based metal–organic polyhedra {[MV5O6(μ3-O)5(SO4)]4[V5O9Cl]4(BTC)12} with undiscovered "near-miss Johnson solid" geometry. Moreover, the variable-temperature magnetic susceptibilities were investigated. [ABSTRACT FROM AUTHOR]

An anthracene modified Anderson–Evans polyoxometalate was polymerized via supramolecular inclusion and then covalent coupling with the support of γ-cyclodextrin (γ-CD) under UV light irradiation. The formed main chain polymers of the inorganic polyanions self-assembled into fibrous bundles and single-strand chains were visualized and characterized via TEM and other techniques. [ABSTRACT FROM AUTHOR]

The 3.5 nm-sized polyanion [H4Te IV48 W VI78 O372]80−, exhibiting an exceptionally high Te : W ratio, expands the structural role of TeIV ions from classical heterogroups within polyoxotungstate subunits to addenda ions. Investigations on the self-assembly conditions, proceeding in a simple one-pot reaction, point to the pH as one critical factor for circumventing this limitation. [ABSTRACT FROM AUTHOR]

MXenes have shown promise in myriad applications, such as energy storage, catalysis, EMI shielding, among many others. However, MXene oxidation in aqueous colloidal suspensions when stored in water at ambient conditions remains a challenge. It is now shown that by simply capping the edges of individual MXene flakes, Ti3C2Tz and V2CTz, by polyanions such as polyphosphates, polysilicates or polyborates, it is possible to quite significantly reduce their propensity for oxidation even when held in aerated water for weeks. This breakthrough resulted from the realization that the edges of MXene sheets are positively charged. It is thus an example of selectively functionalizing the edges differently from the MXene sheet surfaces. [ABSTRACT FROM AUTHOR]

Sulfones are flexible functional groups that can act as nucleophiles, electrophiles, or even radicals. Changing the reaction conditions can completely alter the reactivity of a sulfonyl group, and as a result, molecules bearing multiple sulfones are versatile building blocks. This Review highlights the unique ability of 1,1‐ and 1,2‐bis(sulfones) to masquerade as a vast array of reactive synthons including methane polyanions, vinyl cations, and all‐carbon dipoles that would be difficult or impossible to access directly. [ABSTRACT FROM AUTHOR]

Reactions of inorganic macrocyclic polytungstate cavitands K28Li5H7[P8W48O184]·92H2O or Li17(NH4)21H2[P8W48O184]·85H2O with (NH4)[NbO(C2O4)2(H2O)2]·3H2O (Nb–Ox) in aqueous solution lead to incorporation of up to five {NbO(H2O)}3+ units into the {P8W48} cavity. The most stable species contain four {NbO(H2O)}3+ units. The uptake of {NbO(H2O)}3+ was determined by corroborative methods including single crystal XRD, inductively coupled plasma atomic emission spectroscopy (ICP-AES), 31P and 13C nuclear magnetic resonance (NMR), C–H–N elemental analysis (EA) and thermal gravimetric analysis (TGA). Solution speciation of the Nb-encapsulating macrocycles was studied by HPLC-ICP-AES and small angle X-ray scattering (SAXS). [ABSTRACT FROM AUTHOR]

Although classical homogeneous Fenton reaction systems (FeII + H2O2) are widely used for organic pollutant degradation, this technology has important shortcomings such as waste generation and difficult Fe2+ recycling. These shortcomings originate secondary pollution issues and make it difficult to control the reactions. Polyoxometalates (POMs) are characterized by bearing large electron‐donating conjugate systems able to stabilize Fe2+. To explore a new kind of heterogeneous Fenton reagent, we prepared a new‐type of stable heterogeneous Fenton reagent, (H3O)3.5(H3DETA)3.5{FeII[H4MoV6O15(PO4)4]2} (DETA = diethylenetriamine) (1) by inserting FeII into the POMs. The sandwich‐type 1 was excited by ultraviolet (UV) light, showed high efficiency as a solid‐phase Fenton catalyst, and can be potentially recycled to control the reactions. The coordinating reaction mechanisms for the catalytic degradation of methyl orange (MO) over the 1 + H2O2 reaction system was studied, including photocatalysis and Fenton oxidation effects. As a contrast, another new phosphomolybdate, (H3DETA)4{ZnII[H5MoV6O15(PO4)4]2}·7.5H2O (2), which has the same sandwich‐type polyanion but ZnII acting as the sandwich‐atom, has also been synthesized, characterized. The comparative study of photocatalytically degrading MO has also been carried out. In addition, by studying the thermal decomposition behavior of 1, we revealed, for the first time, the presence of Mo4P3 as a decomposition residue of 1. [ABSTRACT FROM AUTHOR]

Polyelectrolytes (PEs) bearing easily derivatizable functions for possible post-modification under mild conditions can find a broad range of applications in various fields. The present paper describes the successful controlled side-chain allylation of two types of PEs: polyamine-based polycations, i.e. poly(allylamine hydrochloride) (PAH) and branched polyethyleneimine (PEI), and strong polyanions, i.e. poly(sodium vinyl sulfonate) (PVS) and poly(sodium 4-styrene sulfonate) (PSS). PSS has been largely investigated in the literature, while PVS is much less commonly explored. The allylation of each type presents its own drawback, i.e. heterogeneous reaction in the case of strong polyanions and instability of partially protonated allylated polyamine products. Nevertheless, all encountered difficulties could be solved and thoroughly elucidated by different experimental tests. This partial allyl-functionalization does not affect the electrolytic properties of the newly allylated PEs, as evidenced by the effective construction of two series of polyelectrolyte multilayer (PEM) films, namely PEI-ene (PSS-ene/PAH-ene)4 and PEI-ene (PVS-ene/PAH-ene)4, the latter being one of the rare examples developed in the literature. The presence of allyl groups on the PE side-chains allows for the stabilization of the resulting PEM films via thiol-ene photo-crosslinking in the presence of a water-soluble dithiol crosslinker. In order to fix permanently the resulting crosslinked PEM films on substrates, the covalent crosslinking occurs not only between different C=C bonds on PE layers but also with those present on substrates preliminarily functionalized with allyl groups via sulfur–gold chemistry. The robustness of both resulting crosslinked PEM films under strongly basic solution (pH 14) is validated by Quartz Crystal Microbalance (QCM) measurements. The versatility and effectiveness of the present approach is expected to find potential applications in different scientific and technological fields. [ABSTRACT FROM AUTHOR]

Novel conducting polymers doped with siloxane-based polyanion have been synthesized and their mechanical and thermoelectric properties were investigated. Free-standing properties and flexibility of these polymer films were compared with conducting polymers doped with conventional polyanion composed of carbon-carbon backbone. Thermoelectric properties were found to not be affected by the chemical structures of dopant polyanions. [ABSTRACT FROM AUTHOR]

Gaucher and Fabry diseases are the most prevalent sphingolipidoses. Chronic inflammation is activated in those disorders, which could play a role in pathogenesis. Significant degrees of amelioration occur in patients upon introduction of specific therapies; however, restoration to complete health status is not always achieved. The idea of an adjunctive therapy that targets inflammation may be a suitable option for patients. PPS is a mixture of semisynthetic sulfated polyanions that have been shown to have anti-inflammatory effects in mucopolysaccharidosis type I and II patients and animal models of type I, IIIA and VI. We hypothesized PPS could be a useful adjunctive therapy to inflammation for Gaucher and Fabry diseases. The objective of this work is to analyze the in vitro effect of PPS on inflammatory cytokines in cellular models of Gaucher and Fabry diseases, and to study its effect in Gaucher disease associated in vitro bone alterations. Cultures of peripheral blood mononuclear cells from Fabry and Gaucher patients were exposed to PPS. The secretion of proinflammatory cytokines was significantly reduced. Peripheral blood cells exposed to PPS from Gaucher patients revealed a reduced tendency to differentiate to osteoclasts. Osteoblasts and osteocytes cell lines were incubated with an inhibitor of glucocerebrosidase, and conditioned media was harvested in order to analyze if those cells secrete factors that induce osteoclastogenesis. Conditioned media from this cell cultures exposed to PPS produced lower numbers of osteoclasts. We could demonstrate PPS is an effective molecule to reduce the production of proinflammatory cytokines in in vitro models of Fabry and Gaucher diseases. Moreover, it was effective at ameliorating bone alterations of in vitro models of Gaucher disease. These results serve as preclinical supportive data to start clinical trials in human patients to analyze the effect of PPS as a potential adjunctive therapy for Fabry and Gaucher diseases. [ABSTRACT FROM AUTHOR]

A unique coupled redox biomimetic catalytic system using the Anderson-type polyoxometallate (POM) (NH4)3Co(OH)6Mo6O18 and p-toluenesulfonic acid (p-TsOH)-based deep eutectic solvents (DESs) as cocatalysts, which served as electron donors and electron-transfer mediators (ETMs), can selectively oxidize the sulfides in diesel into their corresponding sulfones. The use of coupled redox systems with ETMs facilitates the reaction process by transporting electrons from Co-POM to the oxidant along a low-energy pathway, making DBT prone to oxidize to DBTO2. The biomimetic system demonstrates outstanding desulfurization performance with oxygen as an oxidant in the absence of sacrificial agents and under mild conditions. [ABSTRACT FROM AUTHOR]

Sodium 9,10‐anthraquinone‐2,6‐disulfonate (Na2AQ26DS), with polyanionic character and two O−Na ionic bonds, is found to be a highly stable organic cathode in Na‐ion batteries, delivering capacities of approximately 120 mAh g−1 for 300 cycles (50 mA g−1) and around 99 mAh g−1 for 1000 cycles (1 A g−1). These results are the best performance reported to date for small‐molecule, anthraquinone‐based organic cathodes in Li‐, Na‐, or K‐ion batteries. [ABSTRACT FROM AUTHOR]

A series of new Ln14-substituted polyoxometalates, H27Na16[(Ln14(H2O)W4(OH)O14)(WO4)4(GeW10O38)6]·nH2O (n≈ 86) (1-Ln, Ln = Eu, Gd, Tb, Dy, Ho, Er), which contain 14 Ln3+ and 6 {α(1,5)-[GeW10O38]12−} units, has been synthesized in one-pot reactions. As the first 14-Ln-containing polyoxometalates, the octahedron-shaped three-shell structure of the [(Ln14(H2O)W4(OH)O14)(WO4)4(GeW10O38)6]43− polyanion is made up of a W4 tetrahedron, a Ln14W4 tetrahedron and a Ge6W60 octahedron. Compound 1-Dy exhibits frequency dependent magnetic properties. Compounds 1-Eu, 1-Tb and 1-Dy exhibit the characteristic emission bands of the Ln3+ ion. [ABSTRACT FROM AUTHOR]

Abstract: Bacterial cellulose nanocrystals (BCNCs) have hydrophilic surfaces due to hydroxyl groups but are water-insoluble. The carboxymethylation improves the solubility of cellulose in polar media through the insertion of carboxymethyl groups. This study aims to evaluate the use of two different alcoholic solvents in the carboxymethylation reaction of BCNCs: ethanol and isopropanol. BCNCs were obtained under two hydrolysis conditions: sulfuric acid (BCNC-S) and combination of sulfuric and hydrochloric acids (BCNC-S/Cl). Two techniques (NMR and titration) were used to determine the degree of substitution (DS) values. Carboxymethylation of BCNC-S/Cl led to high DS compared to BCNC-S and the use of isopropanol promoted an even greater DS. The thermal properties were not affected after the chemical modification. However, functionalization provided an increase in the negative charge density at the surface of nanostructures and a change in the crystal structure (cellulose type Iα for amorphous), making this material a potential polyanion for the synthesis of polyelectrolyte complexes (PECs). The micrographs showed that the nanocrystals became soluble after carboxymethylation. Carboxymethylated bacterial cellulose nanocrystals hydrolyzed through the mixture of inorganic acids and modified using isopropanol (CBCNC-S/Cl-IPA) was a suitable polyanion to produce PECs with chitosan. The PECs produced had particle size ranging from 276 to 588 nm and zeta potential ranging from − 24.3 to + 39.0 mV.Graphical abstract: [ABSTRACT FROM AUTHOR]

A series of Keggin heteropolytungstate salts (M1.5PW12O40, M=Cu, Co, Zn and Fe) were prepared and characterized utilizing inductively coupled plasma spectrometry (ICP), Fourier transform infrared (FTIR) spectra, and ultraviolet-visible (UV-Vis) light spectroscopy. The as-prepared catalysts were tested for the oxidation of ethylbenzene by using carbon dioxide/hydrogen peroxide (CO2/H2O2) as the oxidizing agent system under solvent-free conditions. The results indicated that the heteropolytungstates catalyzed the side chain oxidation of ethylbenzene leading to acetophenone as a major product. The effect of various reaction parameters on ethylbenzene oxidation over the best catalyst of the series, namely Co1.5PW12O40 loaded on activated carbon (AC), was investigated. It was found that the selectivity depends strongly on the reaction temperature. Higher reaction temperatures reduce the conversion due to the decomposition of H2O2. Oxidation by a large amount of H2O2 decreases the conversion owing to a decrease of the solubility of ethylbenzene in an aqueous medium, and favors the oxidation of the reaction products, which are more soluble in an aqueous medium. The increase of the CO2 pressure improves both the conversion and the selectivity of acetophenone due to the involvement of the percarbonate species (HCO4−) responsible for oxidation by oxygen transfer. [ABSTRACT FROM AUTHOR]

We report on the synthesis and structural characterization of four bismuth(III)‐containing sandwich‐type heteropolytungstates with Bi in 8‐coordination. The three isostructural Keggin‐type ions [Bi(α‐XW11O39)2]n– {X = Si (1), Ge (2), n = 13; X = P (3), n = 11} and the Wells–Dawson‐type ion [Bi(α2‐P2W17O61)2]17– (4) were prepared via simple one‐pot synthetic procedures in aqueous medium. The novel polyanions comprise a Bi3+ ion linking two monolacunary {XW11} or {X2W17} units in a sandwich‐type fashion. The Bi3+ ion is coordinated by four oxygens of each monolacunary POM unit, resulting in 8‐coordination with square‐antiprismatic geometry. Such a coordination mode is rare for Bi3+. We demonstrate that bismuth(III) can link two monolacunary Keggin‐ and Dawson‐type heteropolytungstates resulting in sandwich‐type structures with 8‐coordinated bismuth(III) in square‐antiprismatic coordination geometry. The four novel polyanions were characterized in the solid state and in solution. [ABSTRACT FROM AUTHOR]

Keggin phosphotungstate heteropolyanions (HPA), PW12O403–, are known to interact via short‐range attraction and long‐range repulsion (SALR) at moderate and high solution concentrations and low‐pH (pH = 1). These interactions were identified through the observation of structure factor peaks in small‐angle X‐ray scattering (SAXS) data reported previously (J. Phys. Chem. C2016, 120, 1317). Here we describe the interactions between the same heteropolyanions with extremely low concentrations at low (pH = 0) and high pH (pH = 4.7) conditions. The solution chemistry of Keggin heteropolyanions at these two pH values provides a unique way to change the charge of the cluster anions without changing the structure (from the perspective of SAXS) and, at the same time, changing the hydrogen bonding interactions. The structure factors obtained from concentration dependent SAXS data reveal that the change in pH changes the nature of SALR interactions, consistent with the presence of the plenary PW12O403− anion at pH = 0 and the monovacant lacunary PW11O397– anion at pH = 4.7. At the low pH condition, the attractive interactions dominate to provide a peak near Q = 0 Å−1 momentum transfer in the structure factors, whereas at pH = 4.7 the repulsive interactions dominate, thereby eliminating the peak near Q = 0 Å−1. The experimental results presented here are in agreement with the recent liquid state theory and computer simulation predictions on SALR interactions. At low concentrations, heteropolyanions exhibit pH‐dependent interactions that can go from hydrogen bonding mediated short‐range attractions at low‐pH to coulombic long‐range repulsions at high‐pH conditions. [ABSTRACT FROM AUTHOR]

The nonclassical heteropolyoxotungstate [P3W6(O2)6(OH)2O22]7– has been successfully synthesized and characterized well by various techniques such as FT‐IR, UV/Vis, TGA, as well as elemental analysis. The single‐crystal X‐ray analysis reveals that the two {PW3(O2)3(OH)O9} subunits are linked together through a {PO4} group, forming a nonclassical type of phosphotungstate polyanionic framework. Furthermore, the solution behaviour of the title compound has been investigated by UV/Vis spectroscopy, electrospray ionization mass spectrometry and 31P nuclear magnetic resonance spectroscopy. The structure of compound 1 consists of two similar {P2W3(O2)3(OH)O13} subunits connected through a {PO4} group, forming a hourglass‐shaped architecture head‐to‐head. In addition, the solution behavior of 1 has also been investigated by UV/Vis, ESI‐MS and 31P NMR spectroscopy. [ABSTRACT FROM AUTHOR]

We report the adsorption characteristics and mechanisms of a strong polyanion, poly(styrenesulfonate), PSS, onto α-Al2O3 with large size (L-Al2O3) and small size (S-Al2O3) in this paper. Some effective conditions to the adsorption of PSS onto L-Al2O3 and S-Al2O3 such as adsorption time, pH, mass ratio of PSS to α-Al2O3, and ionic strength were systematically studied. Maximum adsorption capacities of PSS onto both L-Al2O3 and S-Al2O3 were achieved with adsorption time 120 min, mass ratio of PSS to α-Al2O3 20 mg/g, and ionic strength 50 mM NaCl. The PSS adsorption onto S-Al2O3 significantly decreased with increasing pH from 4 to 9 while PSS adsorption onto L-Al2O3 decreased insignificantly in the pH range 4-9. Adsorption of PSS onto both L-Al2O3 and S-Al2O3 increased with increasing salt from 0 to 50 mM NaCl, indicating that electrostatic and none-lectrostatic interactions controlled adsorption at low ionic strength. However, adsorption of PSS was independent on the ionic strength at salt concentration higher than 50 mM. The changes in surface charge after PSS adsorption onto L-Al2O3 and S-Al2O3 were determined by zeta potential while the differences of surface functional groups before and after PSS adsorption were characterized by Fourier-transform infrared spectroscopy (FT-IR). The zeta potential as a function of the mass ratio of PSS to L-Al2O3 and S-Al2O3 agreed well with the adsorption capacity against the mass ratio. Adsorption mechanisms of PSS onto L-Al2O3 and S-Al2O3 were also discussed based on the changes in zeta potential, the differences of surface functional groups, and adsorbed amount as a function of the mass ratio of PSS to α-Al2O3.ᅟ [ABSTRACT FROM AUTHOR]

Organic pollutants contaminate water resources and the environment when discharged into water streams. Also, the presence of these materials in incompletely treated or untreated wastewater leads to serious environmental hazards. The hydroxyl radicals and holes are regarded as the most oxidant species in the degradation of organic pollutants using the studied composites. The results of this review show that heteropoly acids on supporting materials could be considered as appropriate photocatalysts in the removal of organic pollutant from aqueous solutions.

K6Mn4O7 was synthesized via the azide/nitrate route from a stoichiometric mixture of the precursors KN3, KNO3, and MnO, and alternatively from the binary constituents K2O and MnO, in an all‐solid state reaction. Its crystal structure [P1, Z = 1, a = 603.46(3), b = 647.69(4), c = 891.36(5) pm, α = 90.477(2)°, β = 108.417(2)°, γ = 115.358(2)°] consists of cluster‐like Mn4O10 units, each composed of four edge sharing MnO4 tetrahedra. The Mn4O10 building blocks, on their part, are linked by six vertices, forming a 2D arrangement, 2∞[Mn4O4/1O6/2]n6–, with the potassium cations occupying the space in between. The temperature dependence of the magnetic susceptibility is dominated by antiferromagnetic coupling along a low‐dimensional magnetic exchange path. The heat capacity reveals no clear sign of long‐range magnetic ordering, supporting an interpretation of K6Mn4O7 as a new low‐dimensional magnetic system. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Amidst the ever-rising threat of antibiotics resistance, colistin, a decade-old antibiotic with lingering toxicity concern, is increasingly prescribed to treat many drug-resistant, gram-negative bacteria. With the aim of improving the safety profile while preserving the antimicrobial activity of colistin, a nanoformulation is herein developed through coacervate complexation with polyanionic peptides. Upon controlled mixing of cationic colistin with polyglutamic acids, formation of liquid coacervates was demonstrated. Subsequent stabilization by DSPE-PEG and homogenization through micro-fluidization of the liquid coacervates yielded nanoparticles 8 nm in diameter. In vitro assessment showed that the colistin antimicrobial activity against multiple drug-resistant bacterial strains was retained and, in some cases, enhanced following the nanoparticle assembly. In vivo administration in mice demonstrated improved safety of the colistin nanoparticle, which has a maximal tolerated dose of 12.5 mg/kg compared to 10 mg/kg of free colistin. Upon administration over a 7-day period, colistin nanoparticles also exhibited reduced hepatotoxicity as compared to free colistin. In mouse models of Klebsiella pneumoniae bacteremia and Acinetobacter baumannii pneumonia, treatment with colistin nanoparticles showed equivalent efficacy to free colistin. These results demonstrate coacervation-induced nanoparticle assembly as a promising approach towards improving colistin treatments against bacterial infections. Statement of Significance Improving the safety of colistin while retaining its antimicrobial activity has been a highly sought-after objective toward enhancing antibacterial treatments. Herein, we demonstrate formation of stabilized colistin nanocomplexes in the presence of anionic polypeptides and DSPE-PEG stabilizer. The nanocomplexes retain colistin's antimicrobial activity while demonstrating improved safety upon in vivo administration. The supramolecular nanoparticle assembly of colistin presents a unique approach towards designing antimicrobial nanoparticles. [ABSTRACT FROM AUTHOR]

The self‐assembly reaction towards the archetypal antimonato polyoxovanadate {V15Sb6} in the presence of two organic amines, 1‐(2‐aminoethyl)piperazine (aep) and diethylenetriamine (dien), and a simple NiII salt yields the compound {Ni(dien)2}2[(aepH)2V15Sb6O42(H2O)]·7.5H2O in which secondary [Ni(dien)2]2+ coordination complexes and covalent Sb–Naep bonds coexist. The latter augment the spherical [V15Sb6O42(H2O)]6– cluster core by two protonated aep groups that effectively reduce the polyanion's charge. The terminal NH3 groups of the two crystallographically independent aep units interlink two adjacent cluster anions through strong N–H···O interactions. In the solid state, this results in a tight 3D network of Sb–N and hydrogen bonds, which only starts to release its crystal water above 150 °C. As anticipated from its structure, the magnetic properties of the title compounds can be modeled using an additive approach. [ABSTRACT FROM AUTHOR]

A library of 16 digitally encoded polyanions was used in a layer‐by‐layer (LbL) polyelectrolyte assembly to nanofabricate thin films containing digitally coded strata. The polyanions were digital polyphosphodiesters (d‐PPDE) prepared via an automated phosphoramidite process. Each component of the library contained 10 bytes of ASCII‐encoded text (i.e. 80 coded monomers); thus the entire library allows the writing of a full sentence, which can be stored in a multilayer film as a sequence of sequences. To prepare fully segregated digital domains, non‐coded layers composed of poly(allylamine hydrochloride) (PAH)/poly(sodium 4‐styrenesulfonate) (PSS) were included between the d‐PPDE coded layers as an intermediate barrier. Detailed analysis of the film homogeneity indicated formation of 70 nm‐thick films in which digital layers are kept apart from another by non‐coded interlayers. As a result, the sequence‐coded polymer library could be piled‐up in a defined sequence of layers. Thin films containing segregated layers of digitally encoded polymers were prepared and characterized. An ASCII‐encoded sentence of 160 bytes was stored in these films using a library of 16 different digital polyanions. The results show that abiotic coded matter can be organized in precise nanoscale morphologies. [ABSTRACT FROM AUTHOR]

The stannides REIr2Sn4 (RE=La, Ce, Pr, Nd, Sm) were synthesized from the elements by arc melting or by induction melting in sealed niobium containers. They crystallize with the NdRh2Sn4 type structure, space group Pnma. The samples were characterized by powder X-ray diffraction (Guinier technique). Three structures were refined from single-crystal X-ray data: a=1844.5(2), b=450.33(4), c=716.90(6) pm, wR2=0.0323, 1172 F2 values, 44 variables for LaIr2Sn4, a=1840.08(2), b=448.24(4), c=719.6(1) pm, wR2=0.0215, 1265 F2 values, 45 variables for Ce1.13Ir2Sn3.87, and a=1880.7(1), b=446.2(1), c=733.0(1) pm, wR2=0.0845, 836 F2 values, 45 variables for Ce1.68Ir2Sn3.32. The structures consist of three-dimensional [Ir2Sn4] polyanionic networks in which the rare earth atoms fill pentagonal prismatic channels. The striking structural motif concerns the formation of solid solutions RE1+xIr2Sn4−x on the Sn4 sites, which have similar coordination as the RE sites. Temperature dependent magnetic susceptibility measurements revealed diamagnetic behavior for LaIr2Sn4. CeIr2Sn4, PrIr2Sn4 and NdIr2Sn4 show Curie-Weiss paramagnetism while SmIr2Sn4 exhibits typical van Vleck paramagnetism. Antiferromagnetic ground states were observed for CeIr2Sn4 (TN=3.3 K) and SmIr2Sn4 (TN=3.8 K). 119Sn Mössbauer spectra show a close superposition of four sub-spectra which can be distinguished through their isomer shift and the quadrupole splitting parameter. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrids consisting of organic cations and polyanions are promising functional materials due to their various compositions and structures. An important aspect of these materials is the interactions between the organic and inorganic components, which not only produce the final structures, but also influence the properties. Here, we investigated the interactions between organic cations and polyanions using protonated 2-aminopyridinium (Hap) as the cation, and successfully obtained two polyoxometalate-based hybrids, namely (C5H7N2)4[Mo8O26 ], (I), and (C5H7N2)2[NiMo6O16(OH)2{CH3C(CH2O)3 }2]·-4H2O, (II). In the crystal structure of (I), every Hap cation links with two polyanions by donating one or two N-H…O hydrogen bonds, and every polyanion is surrounded by eight Hap cations via terminal or bridging O atoms. Conversely, in compound (II), every Hap cation only links with one polyanion decorated by a triol ligand; this organic-inorganic component further assembles via uncoordinated water molecules. In the extended structures, Hap plays a key role, not only providing a counter charge, but also acting as 'glue' linking polyanions in the role of hydrogen-bond donors. In both compounds, as the nodes of the supramolecular network, the polyanions exhibit an ordered twodimensional arrangement due to strong hydrogen bonds and electrostatic interactions between the organic and inorganic parts. The electrochemistry of compound (I) shows that redox sourcing from polyanions is a surface-controlled process. Conversely, the magnetic behaviour of compound (II) indicates dominant antiferromagnetic properties. [ABSTRACT FROM AUTHOR]

As an extension of our continued interest in the preparation of inorganic-organic hybrids, we report the successful hydrothermal synthesis of sodium tris[triaqua(μ-1,10-phenanthroline-2,9-dicarboxylato)dysprosium(III)] silicododecatungstate dodecahydrate, {[DyNa(C14H6N2O4)3(H2O)9(SiW12O40)]·12H2O}n or Na[Dy(PDA)(H2O)3]3[SiW12O40]·12H2O (1), and sodium aqua tris[tetraaqua( μ-4-hydroxypyridine-2,6-dicarboxylato)praseodymium(III)] silicododecatungstate dodecahydrate, {[NaPr(C7H3NO5)3(H2O)13(SiW12O40)]·12H2O}n or Na(H2O)[Pr(pydc-OH)(H2O)4]3[SiW12O40]·12H2O (2) (in which H2PDA is 1,10-phenanthroline-2,9-dicarboxylic acid and H2pydc-OH is 4-hydroxypyridine-2,6-dicarboxylic acid or chelidamic acid). Both compounds have been characterized using elemental analysis, IR spectroscopy and X-ray diffraction methods. Structural characterization by single-crystal X-ray diffraction reveals that these compounds consist of [SiW12O40]4- Keggin-type polyoxometalates (POMs), where a single {W3O13} triad is decorated with a trinuclear Ln complex. Moreover, the decorated polyanions are involved in a series of intermolecular interactions, such as hydrogen bonds and anion-л interactions, resulting in three-dimensional supramolecular architectures. Density functional theory (DFT) studies were conducted to support these intermolecular interactions in both 1 and 2, and have been rationalized using molecular electrostatic potential (MEP) surface calculations. [ABSTRACT FROM AUTHOR]

A new and stable Keggin-type phosphomolybdate based hybrid compound, [Ag4(FKZ)2][HPMo12O40] (HFKZ = [1-(2,4-difluorophenyl)-1,1-bis [(1H-1,2,4-triazol-1-yl)-methyl]methanol], was synthesized and structurally characterized. The flexible coordination mode of HFKZ molecules and Ag ions generate high-connected PMo12 polyanions, as well as synergistically contribute to the formation of quadruple meso-helical structure. The new compound exhibits excellent stability in aqueous solution and different organic solvents and even high pressure, which is expected as an ideal electrocatalytic material due to the multi-electron redox ability of PMo12 polyanions and synergistic effect of all components. The result of the electrochemical behavior indicates that the new compound as active substance exhibits good electrocatalytic activity toward the reduction of nitrite. [ABSTRACT FROM AUTHOR]

Rationale: Polyoxometalates (POMs) are remarkable oxo‐clusters forming compact highly charged anions. We measured their collision cross sections (CCS) in N2 with drift tube ion mobility spectrometry (DTIMS). These values were then used to calibrate a traveling wave ion mobility spectrometry (TWIMS) device and the accuracy of the calibration was tested. Methods: Six POM standards were analyzed by DTIM‐MS (Tofwerk, Thun, Switzerland) at different voltages to determine absolute DTCCS (N2) values. Five POM compounds (Lindqvist TBA2Mo6O19; decatungstate TBA4W10O32; Keggin TBA3PMo12O40; TBA3PW12O40 and Dawson TBA6P2W18O62) were used for the calibration of the TWIM‐MS instrument (Synapt G2 HDMS, Waters, Manchester, UK) and a sixth Dawson POM, TBA9P2Nb3W15O62, was used to compare the accuracy of the calibrations with POM or with polyalanine and dextran reference ions. Results: We determined 45 DTCCS (N2) values at 30°C or 60°C. Fourteen DTCCS (N2) values at 30°C were used to perform calibration of the TWIMS instrument. Better correlations were observed than when DTCCS values in helium from the literature were used. The accuracy tests on six ions of Dawson POM TBA9P2Nb3W15O62 led to relative errors below 3.1% while relative errors of 3.6% to 10.1% were observed when calibration was performed with polyalanine and dextran reference ions. Conclusions: Our novel calibration strategy for determination of CCS values of multiply negatively charged ions on TWIM‐MS devices based on DTCCS (N2) of standard POM structures covered a wider range of CCS and improved the accuracy to 2.1% relative error on average compared with 6.9% using polyalanine and dextran calibration. [ABSTRACT FROM AUTHOR]

The magnetic behavior of the polyanion [Fe3(μ-L)6(H2O)6]6– (L2– = (1,2,4-triazol-4-yl)ethanedisulfonate) as the corresponding dimethylammonium salt shows memory effect above room temperature, with a dynamic thermal hysteresis cycle over 90 K and temperature-induced excited spin state trapping (TIESST) phenomena at the highest temperatures reported. Taking advantage of the polyanionic nature of this trimetallic complex, we were able to substitute the dimethylammonium cations by the monovalent heavy alkali metal cesium. This methathesis yielded the salt Cs6[Fe3(μ-L)6(H2O)6], with different molecular packing that increases the number and strength of cation–anion interactions, including a more robust H-bonded network. In this phase, the spin transition still occurs above room temperature, but it is more abrupt and narrow (≈50 K wide hysteresis). Despite these differences, TIESST is observed with almost identical characteristic temperature (TTIESST = 240 K) than in the parent compound, which is an additional experimental evidence supporting the molecular origin of the TIESST behavior in these materials. [ABSTRACT FROM AUTHOR]

Abstract: The exploration of high‐energy‐density cathode materials is vital to the practical use of K‐ion batteries. Layered K‐metal oxides have too high a voltage slope due to their large K+–K+ interaction, resulting in low specific capacity and average voltage. In contrast, the 3D arrangement of K+, with polyanions separating them, reduces the strength of the effective K+‐K+ repulsion, which in turn increases specific capacity and voltage. Here, stoichiometric KVPO4F for use as a high‐energy‐density K‐ion cathode is developed. The KVPO4F cathode delivers a reversible capacity of ≈105 mAh g−1 with an average voltage of ≈4.3 V (vs K/K+), resulting in a gravimetric energy density of ≈450 Wh kg−1. During electrochemical cycling, the KxVPO4F cathode goes through various intermediate phases at x = 0.75, 0.625, and 0.5 upon K extraction and reinsertion, as determined by ex situ X‐ray diffraction characterization and ab initio calculations. This work further explains the role of oxygen substitution in KVPO4+xF1−x: the oxygenation of KVPO4F leads to an anion‐disordered structure which prevents the formation of K+/vacancy orderings without electrochemical plateaus and hence to a smoother voltage profile. [ABSTRACT FROM AUTHOR]

A plug and socket approach for tightening polyelectrolyte multilayers is introduced based on the use pendant β-cyclodextrin groups. Prototypical multilayers derived from poly(sodium 4-styrene sulfonate) and β-cyclodextrin-containing poly(4-vinylbenzyltrimethylammonium chloride) are described. Evidence for tightened multilayers has been obtained from gas permeation, swelling and quartz crystal microbalance with dissipation (QCM-D) measurements. [ABSTRACT FROM AUTHOR]

Abstract Studies of the synthesis of solid state nitrides using a Na flux are reviewed. The role and effect of Na is to solubilize polyatomic species containing nitrogen, and to lower the crystal growth temperature below the decomposition temperature of the obtained product(s). Many new ternary and quaternary nitrides have been synthesized in single crystal forms with sizes at least large enough (or larger) than is needed for structure analysis by X-ray diffraction. Isolated and extended anionic groups typically containing N and Si, Ge, Ga, and/or some transition metal elements are typical. These are usually surrounded by alkaline-earth atoms and are the most common of such nitrides. Compounds composed of nitridometallate anions and Zintl polyanions are also obtained. The structural features of each of these compounds are described. [ABSTRACT FROM AUTHOR]

Organic pollutants contaminate water resources and the environment when discharged into water streams. Also, the presence of these materials in incompletely treated or untreated wastewater leads to serious environmental hazards. The hydroxyl radicals and holes are regarded as the most oxidant species in the degradation of organic pollutants using the studied composites. The results of this review show that heteropoly acids on supporting materials could be considered as appropriate photocatalysts in the removal of organic pollutant from aqueous solutions. [ABSTRACT FROM AUTHOR]

We studied the conditions for separating rhenium and polyanions (molybdenum and tungsten) by selective extraction of rhenium from the phase of saturated gel-type strongly basic anion exchanger by tertiary amine solution. Rhenium passes quantitatively into the organic phase under both dynamic and static conditions. The optimal parameters of this method of extractive desorption of rhenium are designed, which ensure complete removal of polyanions and other accompanying impurities. In order to make rhenium further pass into the aqueous phase, the extractant is treated with ammonia solution. Ammonia-salt mixtures are recommended to be used for desorption of molybdenum or tungsten polyanions from the strongly basic anion exchangers. [ABSTRACT FROM AUTHOR]

Abstract: In order to explore if and how salts comprising polycations and salts comprising polyanions might interact, the [AlBr4]− salt of the [Pt@Bi10]4+ cluster cation was added to the reaction mixture for the synthesis of the supersphere cluster anion [Ge24Sn36Se132]24− from Cs4[Ge4Se10]⋅H2O and SnCl4⋅5 H2O under ionothermal conditions at 120 °C. Indeed, the reaction yields two new compounds, depending on the cation of the used ionic liquid. Apparently, the polycation is not retained under the given conditions, but it acts as a reductant affording SnII. In a (C4C1C1im)+‐based ionic liquid mixture, a unique supertetrahedral anion is obtained that embeds a Cs+ cation, 0D‐{[Cs@SnII4(GeIV4Se10)4]7−}, while (C4C1im)+ cations stabilize an unprecedented ternary layered anion, 2D‐{[SnII(GeIV4Se10)]2−}. Test reactions with common sources of SnII did not afford the new compounds, indicating the necessity of an in situ reduction, for which the polycation seems appropriate. [ABSTRACT FROM AUTHOR]

It is essential to develop efficient electrode materials for sodium in batteries, which are currently being considered as a promising alternative to lithium-ion batteries. In this work, we are presenting NaMnBO3 nanoparticles with conductive carbon matrix (C-NMB) synthesized by urea-assisted hydrothermalmethod used as a potential cathode material in sodium ion batteries. The C-NMB electrode delivered discharge capacities of 116 mAh g-1, 97 mAh g-1, and 52 mAh g-1 at 0.2 C, 0.5 C, and 2 C rates, respectively and exhibited excellent cyclic behavior at all current densities. Further, the C-NMB electrode demonstrated the best electrochemical stability among other polyanion cathodes, with a capacity fade of 0.06% per cycle at 2 C after 250 cycles with more than 99% coulombic efficiency. X-ray photoelectron spectroscopy revealed that the reduction in oxygen containing surface functionalities (carboxyl groups) further increased the electrical conductivity of the NMB materials. The ex-situ XRD studies after first initial charge and discharge steps reveals that the hexagonal C-NMB electrode displays a topotactic sodium storage mechanism. These outcomes will contribute to the progress of developing low cost, eco-friendly electrode materials for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Here we report a facile method to construct reversible visible-light-responsive switching from antibacterial to bioadhesion by host-guest self-assembly of β-cyclodextrin (β-CD) and azobenzene functionalized polycation/polyanion. The visible-light-responsible azobenzene functionalized polycation, poly{6-[(2,6-dimethoxyphenyl)azo-4-(2′,6′-dimethoxy)phenoxy]propyl dimethylaminoethyl methacrylate-random-poly(2-( N,N -dimethylaminoethyl) methacrylate) (Azo-PDMAEMA), was synthesized via quaternization reaction between 2,6,2′,6′-tetramethoxy-4-(3-bromopropoxy)azobenzene (AzoOMeBr) and poly(2-( N,N -dimethylaminoethyl) methacrylate) (PDMAEMA), and the polyanion, poly{6-[(2,6-dimethoxyphenyl)azo-4-(2′,6′-dimethoxy) phenoxy]hexyl acrylate-random-acrylic acid} (Azo-PAA), was synthesized via esterification reaction between 2,6,2′,6′-tetramethoxy-4-(6-hydroxyhexyloxy) azobenzene (AzoOMeOH) and poly(acryloyl chloride) (PAC) and subsequent hydrolysis reactions. The switch surface could be achieved via the alternate host-guest assembly of Azo-PDMAEMA and Azo-PAA onto a β-CD-terminated substratum (Sub-CD) through visible light irradiation. The positively charged Azo-PDMAEMA with quaternary ammonium groups exhibited antimicrobial properties and few bacteria were adhered on the surface, while the negatively charged Azo-PAA with carboxyl acid groups exhibited excellent bioadhesive properties and a large number of bacteria were adhered. Interestingly, the switch between antibacterial and bioadhesive could be realized upon visible light irradiation via alternate assembly of Azo-PDMAEMA and Azo-PAA. The proposed approach to manufacturing visible-light-responsive surface with reversible and alterable biofunctionality switching between antibacterial and bioadhesive is simple and efficient, which is promising for preparation of multifunctional polymeric surfaces to encounter multifarious demands for the biomedical and biotechnological applications. Statement of Significance Light has attracted great attention in building biointerfaces for its precise spatiotemporal control and convenient operation. However, UV light may damage to biological samples and living tissues, which will limit its applications. This study demonstrates a novel visible-light-responsive surface fabricated through reversible assembly of azobenzene functionalized polycations/polyanions on cyclodextrin (CD)-terminated substrate by host-guest interactions between the visible-light-responsive azobenzene mAzo and CD, which has not been examined previously. It is noted that the azobenzene functionalized polycations show strong antibacterial activities, while the polyanions show excellent bioadhesive properties, as can be switched through the alternate assembly upon visible-light irradiation. This facile and versatile approach to visible-light-responsive surfaces holds great potential for switching of bioadhesion. [ABSTRACT FROM AUTHOR]

Summary: We previously reported that Indian paediatric patients with atypical haemolytic–uraemic syndrome (aHUS) showed high frequencies of anti‐complement factor H (FH) autoantibodies that are correlated with homozygous deletion of the genes for FH‐related proteins 1 and 3 (FHR1 and FHR3) (FHR1/3–/–). We now report that Indian paediatric aHUS patients without anti‐FH autoantibodies also showed modestly higher frequencies of the FHR1/3–/– genotype. Further, when we characterized epitope specificities and binding avidities of anti‐FH autoantibodies in aHUS patients, most anti‐FH autoantibodies were directed towards the FH cell‐surface anchoring polyanionic binding site‐containing C‐terminal short conservative regions (SCRs) 17–20 with higher binding avidities than for native FH. FH SCR17–20‐binding anti‐FH autoantibodies also bound the other cell‐surface anchoring polyanionic binding site‐containing region FH SCR5–8, at lower binding avidities. Anti‐FH autoantibody avidities correlated with antibody titres. These anti‐FH autoantibody characteristics did not differ between aHUS patients with or without the FHR1/3–/– genotype. Our data suggest a complex matrix of interactions between FHR1‐FHR3 deletion, immunomodulation and anti‐FH autoantibodies in the aetiopathogenesis of aHUS. [ABSTRACT FROM AUTHOR]

The Preyssler‐Pope‐Jeannin polyanion [NaP5W30O110]14– (1) was prepared by microwave‐assisted synthesis in only 2 h with a yield comparable to the reported hydrothermal procedure. The purity of 1 was confirmed by FT‐IR and multinuclear NMR (31P, 183W) analysis. The silver(I)‐containing analogue [AgP5W30O110]14– (2) was also prepared by hydrothermal (6 d) as well as microwave‐based (2 h) procedures. Polyanion 2 was characterized in the solid state by FT‐IR, single‐crystal XRD, TGA, and elemental analysis and in solution by 31P and 183W NMR, and ESI‐MS. The antiproliferative activities against human cells as well as the antimicrobial properties towards Gram‐positive and Gram‐negative bacteria were comparatively evaluated for 1 and 2. [ABSTRACT FROM AUTHOR]

Abstract: An acetate‐bridged Ru‐substituted arsenotungstate [H2N(CH3)2]14[As4W40O140{Ru2(CH3COO)}2]⋅22 H2O (1) has been synthesized and structurally characterized. Four Ru atoms occupy the respective lacunary S2 sites of the crown‐shaped polyanion [As4W40O140]28−, and each Ru atom is coordinated by one As atom and five μ2‐O atoms, comprising four from the S2 site and one from the acetate ligand. To the best of our knowledge, this coordination of the Ru atom, with an Ru−As bond length of 2.377(3)–2.387(3) Å, is unprecedented in polyoxometalate (POM) chemistry. Notably, 1 exhibits high efficiency, excellent selectivity, and good recyclability for the oxidation of sulfides with hydrogen peroxide (H2O2). Catalytic oxidation of various sulfides in the presence of 1 gives superior conversion and selectivity for sulfones in acetonitrile, whereas sulfoxides are obtained in methanol. [ABSTRACT FROM AUTHOR]

Abstract: A family of four self‐assembling lipopeptides containing Ala‐Lys peptides attached to a C16 aliphatic chain were synthesised. These compounds form two enantiomeric pairs that bear a diastereomeric relationship to one another (C16‐ l‐Ala‐ l‐Lys/C16‐ d‐Ala‐ d‐Lys) and (C16‐ d‐Ala‐ l‐Lys/C16‐ l‐Ala‐ d‐Lys). These diastereomeric pairs have very different critical micelle concentrations (CMCs). The self‐assembled multivalent (SAMul) systems bind biological polyanions as a result of the cationic lysine groups on their surfaces. For heparin binding, there was no significant enantioselectivity, but there was a binding preference for the diastereomeric assemblies with lower CMCs. Conversely, for DNA binding, there was significant enantioselectivity for systems displaying d‐lysine ligands, with a further slight preference for attachment to l‐alanine, with the CMC being irrelevant. [ABSTRACT FROM AUTHOR]

This article reviews the chemistry of homoatomic polyanions of the early p-block elements (groups 13–15). The focus is on species that have been structurally authenticated in solid-state compounds and/or isolated from solution. The structures, bonding, electronic properties, and formation pathways of these homoatomic species are described in detail. [ABSTRACT FROM AUTHOR]

Herein, two mixed-valence Mn16-containing polyanions, (Mn16) [MnIII10MnII6O6(OH)6(PO4)4(A-a-SiW9O34)4]28− (Mn16-Cs) and [MnIII4MnII12(OH)12(PO4)4(A-a-SiW9O34)4]28− (Mn16-Rb), were successfully fabricated on an indium tin oxide (ITO)-coated glass electrode and a glass carbon electrode (GCE) by a layer-by-layer assembly method. Moreover, four composite films, i.e. [PDDA/Mn16-Cs]n, [PDDA/Mn16-Rb]n, [Mn16-Cs/Rubpy]n, and [Mn16-Rb/Rubpy]n (PDDA: poly(diallyldimethylammonium chloride); Rubpy: tris(2,2′-bipyridyl)ruthenium(ii) chloride; n = 1–10), were constructed for comparison and characterized by UV-visible spectroscopy, cyclic voltammetry (CV), and X-ray photoelectron spectroscopy (XPS). Their electrocatalytic activities towards water oxidation were studied under the same experimental conditions. The results of the controlled experiments indicate that (1) all the four films exhibit expected electrocatalytic activities towards water oxidation; (2) the electrocatalytic activity of Mn16-Cs is better than that of Mn16-Rb in solution and composite films; and (3) the electrocatalytic activities of the composite film [Mn16/Rubpy]n are better than those of the composite film [PDDA/Mn16]n. [ABSTRACT FROM AUTHOR]