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There is an urgent need to develop green catalytic transesterification technology to reduce liquid waste and instrument corrosion. Ionic liquids with controlled activity, easy recovery, and corrosion resistance have great potential as catalysts for transesterification reactions. In this paper, a series of ionic liquids were prepared using imidazole and ammonium compounds as cations, and sulphuric acid, p‐toluenesulfonate, and bistrifluoromethanesulfonate anions as anions. In comparison, the ionic liquid made from imidazole with H2SO4 (IMIHS) was found to be the best catalyst for the esterification reaction with high speed, high activity, low corrosion, and high stability, and its catalytic performance was superior to that of sulphuric acid. The optimum reaction conditions were as follows: the molar ratio of ethanol to acetic acid was 1:1, the catalyst amount was 5 wt.%, the reaction temperature was 80°C, and the reaction time was 120 min. The maximum yield of ethyl acetate was 66.2% under the optimum reaction conditions. The catalytic activity was not declined obviously by reusing six times. The activation energy of the reaction is 48.748 kJ/mol. [ABSTRACT FROM AUTHOR]

A response to the comment by Gernot Frenking, outlining common ground, as well as differences, with regard to a recent paper on charge-shift bonding in quaternary ammonium cations. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis of new selenoloquinoxaline derivatives starting from 2‐chloroquinoxaline‐3‐carbonitrile 1. The compound 1 was subjected to a reaction with selenium metal in the presence of NaBH4 as a reducing agent in ethanol, under a nitrogen atmosphere. This reaction resulted in the formation of the sodium salt of 3‐cyanoquinoxaline‐2‐selenolate, which was subsequently reacted with α‐halogenated carbonyl compounds in situ. This reaction produced a series of newly synthesized 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐substituents. Ethyl 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐carboxylate 3a was hydrolyzed by sodium hydroxide to give the corresponding sodium salt 9. This salt was then refluxed with acetic anhydride to produce oxazinone compound 10. The reaction of compound 10 with ammonium acetate afforded pyrimidoselenolo[2,3‐b]quinoxaline derivative 11. Compound 11 was then chlorinated using phosphorous oxychloride to give the corresponding chlorocompound. [ABSTRACT FROM AUTHOR]

The paper by Gershoni-Poranne and Chen (R. Gershoni-Poranne, P. Chen, Chem. Eur. J. 2017, 23, 4659) gives an incorrect definition of covalent bonding. Furthermore, the assignment of so-called charge shift bonds in ammonium compounds has no physical foundation and is conceptually redundant. [ABSTRACT FROM AUTHOR]

This paper describes a new analytical method, using a combination of ammonium pyrrolidine dithiocarbamate/methyl isobutyl ketone (APDC-MIBK) microextraction and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), for the determination of the concentrations of Cd and Pb in aqueous samples. Only 200 μL of organic solvent was used throughout the entire analysis process, with enhancement factors as high as 25. Recoveries from replicate analyses of natural water [NIST 1640(a)] containing mean concentrations of 3.1 μg Cd L−1 and 9.3 μg Pb L−1 were 95 ± 3 and 104 ± 4%, respectively. The corresponding detection limits were 0.6 μg L −1 for Cd and 0.9 μg L −1 for Pb. The main advantage of this approach is its simplicity in terms of sample preparation, as demonstrated by quantifying the levels of Cd and Pd in real samples, including tap water, groundwater, and seawater, using a standard addition method. [ABSTRACT FROM AUTHOR]

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The Indian Environmental Protection Act (EPA) came into force in 1986 after Bhopal Gas Tragedy. It stipulates that no person or industry or processor shall discharge or emit environmental pollutants in excess of prescribed standards. Dihydroxyl ammonium 5,5′-bistetrazole-1,1′-diolate, abbreviated as TKX-50, was synthesized in this laboratory. During synthesis of TKX-50 a large volume of effluent was generated, which was acidic and hazardous in nature and therefore can damage the environment if discharged without proper treatment. Literature survey reveals that TKX-50 effluent analysis and its treatment have not been reported so far. In order to meet EPA norms and protect the environment TKX effluent samples of different steps of synthesis were collected and analyzed for environmental parameters such as pH, chemical oxygen demand (COD), bio-chemical oxygen demand (BOD), total dissolved solids (TDS) and bioassay test (toxicity to zebra fish survival) followed by the treatment of composite effluent. This paper presents analysis results of TKX-50 effluent samples before and after treatment. The results of finally treated TKX-50 effluent indicate that the same can be safely discharged on land for irrigation without adverse effect on environment. This study may be suitable for environmentalists and community of high energy materials. [ABSTRACT FROM AUTHOR]

A novel and efficient approach to sulfonamides has been developed. Using TBHP as the oxidant and NH4I (20 mol%) as the catalyst, arylsulfonyl hydrazides reacted with amines to provide sulfonamides in moderate to good yields. Possible reaction pathway for the formation of the products was also discussed in this paper. [ABSTRACT FROM AUTHOR]

Spray water quality parameters such as hardness, pH, alkalinity, turbidity, and total dissolved solids (TDS) can influence the performance of herbicides. Polyvalent cations found in hard water can reduce the efficacy of post‐emergence herbicides that are weak acids. Various approaches have been proposed to mitigate the negative effects of spray water properties on herbicide performance. Water conditioning adjuvants are designed for overcoming the adverse effects of hard water. One group of adjuvants are nitrogen containing compounds such as ammonium sulfate (AMS). The ability of AMS to overcome hard water antagonism is well‐documented but the positive effect of other ammonium compounds are variable and depend on herbicides and weed species. Other adjuvant groups that can overcome effects of poor spray quality are ethoxylated amine surfactants, organic acids and ethylenediaminetetraacetic acid (EDTA). Water quality is poor in many parts of the world, and accordingly, the study of water property effects on herbicide performance is needed to optimize use, and prevent overuse, of herbicides. [ABSTRACT FROM AUTHOR]

Herein, the authors developed a new and potential semi‐interpenetrating polymer network (semi‐IPN) hydrogels of poly vinyl alcohol (PVA), acryl amide and diallyldimethyl ammonium chloride employing chemical cross‐linker N, N'‐methylene bisacrylamide (NNMBA) and ammonium persulphate as an initiator by radical polymerisation. To analyse the copolymer formation between two monomers and IPN cross‐linking reaction, the resulting hydrogel was characterised by Fourier transform infrared spectroscopy and the surface morphology was analysed using scanning electron microscopy. Differential scanning calorimetry and X‐ray diffraction studies were also carried out for investigating drug loading and distribution and swelling experiments were carried out for the uptake of water. In vitro release of ciprofloxacin hydrochloride from hydrogel was performed at intestinal conditions. The amount of PVA, NNMBA and total monomer concentration was found to strongly control the drug release behaviour from the hydrogels. [ABSTRACT FROM AUTHOR]

A thorough thermodynamic analysis by isothermal titration calorimetry of allosteric and chelate cooperativity effects in divalent crown ether/ammonium complexes is combined with DFT calculations including implicit solvent on the one hand and large-scale molecular dynamics simulations with explicit solvent molecules on the other. The complexes studied exhibit binding constants up to 2×106 m−1 with large multivalent binding enhancements and thus strong chelate cooperativity effects. Slight structural changes in the spacers, that is, the exchange of two ether oxygen atoms by two isoelectronic methylene groups, cause significantly stronger binding and substantially increased chelate cooperativity. The analysis is complemented by the examination of solvent effects and allosteric cooperativity. Such a detailed understanding of the binding processes will help to efficiently design and construct larger supramolecular architectures with multiple multivalent building blocks. [ABSTRACT FROM AUTHOR]

Peritonitis is a disease caused by bacterial strains that have become increasingly resistant to many antibiotics. The development of alternative therapeutic compounds is the focus of extensive research, so novel nanoparticles (NPs) with activity against antibiotic-resistant bacteria should be developed. In this study, the antibacterial activity of quaternary ammonium polyethyleneimine (QA-PEI) NPs was evaluated against Streptococcus viridans, Stenotrophomonas maltophilia and Escherichia coli. To appraise the antibacterial activity, minimal inhibitory concentration (MIC), minimal bactericidal concentration and bactericidal assays were utilised with different concentrations (1.56-100 μg/ml) of QA-PEI NPs. Moreover, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and annexin V/propidium iodide toxicity assays were performed in cell cultures. MICs for S. maltophilia and E. coli isolates were 12.5 and 25 μg/ml, respectively, whereas the MIC for S. viridans was 100 μg/ml. Furthermore, the growth curve assays revealed that these QA-PEI NPs at a concentration of 12.5 μg/ml significantly inhibited bacterial growth for the bacterial isolates studied. On the other hand, QA-PEI NPs lacked significant toxicity for cells when used at concentrations up to 50 μg/ml for 48 h. The present findings reveal the potential therapeutic value of this QA-PEI NPs as alternative antibacterial agents for peritonitis, especially against Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

A detailed molecular understanding of the mechanisms of the dephosphorylation of phosphate triesters due to nucleophilic attack can be very useful for the design of nucleophiles that are more efficient. In this work, we report a combined experimental and theoretical study of the reaction of hydroxylamine with paraoxon. The profile of the reaction rate according to pH was determined, and it was found that protonated hydroxylamine was unreactive, while the neutral form reacted via the zwitterion tautomer, with an overall free energy barrier of 23.0 kcal mol‐1. The anionic form was the most reactive, with a free energy barrier of 18.1 kcal mol‐1. Computational calculations revealed 2 mechanisms for the nucleophilic attack of the zwitterion form: the usual backside attack and a new frontside attack mechanism. The former proceeded according to a 2‐step associative mechanism, while the latter was a concerted single‐step mechanism involving attack of the hydroxylamine oxygen on the phosphorus center and interaction of the NH3+ group with the oxygen of the P═O group. The calculations indicated that the free energy barrier for the frontside attack was more favorable than the backside attack by 3 kcal mol‐1, supporting the notion that the observed reaction occurs by frontside attack. The reaction with the anionic hydroxylamine form occurred according to a single‐step concerted ANDN mechanism. This paper presents a one‐step front side ANDN low‐barrier energy profile alternative route to the classic backside mechanism AN + DN for the dephosphorylation of paraoxon by hydroxylamine applying computational methods supported by experimental evidences. [ABSTRACT FROM AUTHOR]

Single crystals of tungsten double salt (NH4)3WO2F5 = (NH4)3[WO2F4]F have been synthesized by solid-state reaction or from fluoride solution and its crystal structures at 296 and 193 K were determined by X-ray diffraction. At room temperature, the crystal structure of the compound is dynamically disordered with the ligand atoms statistically distributed on two positions (6 e and 24 m) of the Pm3 m unit cell [ a = 6.0298 (1) Å], and the tungsten atom dynamically disordered on 12 orientations forming a spatial cuboctahedron [W12] that enables the real geometry of cis-WO2F4 octahedron to be determined with two short W-O distances. On cooling, the compound undergoes a first-order phase transition with the symmetry change Pm3 m→ Pa3 and a doubling of the unit-cell parameter [ a = 11.9635 (7) Å]. The ligand F(O) atoms statistically occupy two general 24 d sites and form W1 X6 and W2 X6 octahedra, in which the O and F atoms are not crystallographically different that means a static orientational disorder of (NH4)3WO2F5. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title salt, C12H24N+·C2H2BrO2−, contains a dicyclohexylammonium cation connected to a bromoacetate anion by means of an N-H...O hydrogen bond. In the crystal, the ion pairs assemble via N-H...O interactions, forming zigzag infinite chains parallel to the c axis with the (...H-N-H...O-C-O...) n motif that is considered to be a prerequisite for ensuring gelation properties of secondary ammonium monocarboxylate salts. The title salt was characterized by FT-IR, X-ray powder diffraction (XRPD), TG-DTA and 1H NMR spectroscopy in solution. Gelation experiments revealed that dicyclohexylammonium bromoacetate forms molecular gels with dimethylformamide and dimethyl sulfoxide. Scanning electron microscopy (SEM) was used to reveal morphological features of dried gels. [ABSTRACT FROM AUTHOR]

A practical straightforward synthesis of medicinally important NH‐δ‐lactams through the three‐component Castagnoli‐Cushman reaction of 3‐arylglutaconic anhydrides with carbonyl compound and ammonium acetate has been developed. The scope of the protocol has been thoroughly explored paying particular attention to the carbonyl component using wide array of aliphatic and aromatic aldehydes as well as rarely involved cyclic and acyclic ketones. Synthetic potential of prepared compounds was demonstrated by a series of post‐modifications, including unexpected isomerization. [ABSTRACT FROM AUTHOR]

BACKGROUND: The so‐called 'Neapolitan limmo' or 'lemoncetta Locrese' is an old and now rare Mediterranean sweet lime, similar to lemon but smaller. It is a fruit distinguished from orange, lemon, mandarin, and lime for its sweeter, watery, and non‐acidic taste, with a pH between 5.6 and 5.9. No compositional studies are currently available for this citrus fruit. Here we report, for the first time, the distribution in the limmo juice of free amino acids and their main derivatives such as betaines and related ammonium compounds. RESULTS: Seven proteinogenic amino acids (proline, asparagine, serine, aspartic acid, glutamine, alanine, and threonine) and a non‐protein amino acid (γ‐aminobutyric acid) characterize Neapolitan limmo juice. Proline betaine is the predominant betaine. The data were compared with those of other important citrus juices. CONCLUSION: The specific 'taste quality' of Neapolitan limmo juice can be attributed to its peculiar composition in amino acids. The species‐specific presence of the ammonium compound derivatives of the amino acid proline, with proline betaine as the predominant betaine, characterize the non‐acidic varieties of Mediterranean sweet lime. Our study constitutes an important step towards the repopulation of this ancient plant and its exploitation in food industry. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Novel gemini (tail‐head‐spacer‐head‐tail) bis‐quaternary ammonium compounds (bis‐QACs) with a biphenyl spacer between two pyridinium heads were synthesized and compared with commonly used antiseptics such as benzalkonium chloride (BAC) and chlorhexidine digluconate (CHG). The series of compounds showed high inhibitory activity against five bacterial strains and two fungi. The compounds, which contain C8H17‐C10H21 aliphatic tails best within the series. A counterion change does not affect MIC in general. Cytotoxicity on human embryonic kidney cells and haemolysis were also investigated. For bis‐QACs cytotoxic effect was lower than for 3,3′‐[1,4‐phenylenebis(oxy)]bis(1‐dodecylpyridinium) dibromide (3PHBO‐12), that is their closest structural analogue, and for BAC. [ABSTRACT FROM AUTHOR]

We report on the structural and luminescence properties of a series of d10 dicyanometallate compounds of formula K3(Me4N)2[M(CN)2]5 (M = Au and Ag). These double salts form isostructural 3D networks in which metallophilic bonding is observed between [M(CN)2]– subunits. Despite their similar structural features, stark differences in luminescence behavior between these crystals are observed. At room temperature Au‐containing crystals are bright emitters at 405 nm while the Ag analog is a weak emitter at 470 nm. At low temperatures the emission of both complexes becomes intense under UV light at a wavelength of 416 nm. Using lifetime measurements, X‐ray crystallography, and Density Functional Theory (DFT) calculations we have been able to assign these emission bands as a transition from a metal‐metal to ligand charge transfer. Networks of [Au(CN)2]– and [Ag(CN)2]– using the cation tetramethylammonium are structurally and photophysical characterized. Temperature‐ and time‐dependent luminescence, supported with DFT calculations, indicate a temperature dependent dual fluorescence/phosphorescence emission pathway in the case of Au. [ABSTRACT FROM AUTHOR]

Methylammonium lead trihalides and their derivatives are photovoltaic materials. CH3NH3PbI3 is the most efficient light harvester among all the known halide perovskites (PSCs). It is regarded as unsuitable for long‐term stable solar cells, thus it is necessary to develop other types of PSC materials to achieve stable PSCs (Wang et al., Nat. Energy 2016, 2, 16195). Because of this, various research efforts are on‐going to discover novel lead‐based or lead‐free single/double PSCs, which can be stable, synthesizable, transportable, abundant and efficient in solar energy conversion. Keeping these factors in mind, we report here the electronic structures, energetic stabilities and some materials properties (viz. band structures, density of states spectra and photo‐carrier masses) of the PSC chloroammonium lead triiodide (ClNH3PbI3). This emerges through compositional engineering that often focuses on B‐ and Y‐site substitutions within the domain of the BMY3 PSC stoichiometry. ClNH3PbI3 is found to be stable as orthorhombic and pseudocubic polymorphs, which are analogous with the low and high temperature polymorphs of CH3NH3PbI3. The bandgap of ClNH3PbI3 (values between 1.28 and 1.60 eV) is found to be comparable with that of CH3NH3PbI3, (1.58 eV), both obtained with periodic DFT at the PBE level of theory. Spin orbit coupling is shown to have a pronounced effect on both the magnitude and character of the bandgap. The computed results show that ClNH3PbI3 may act as a competitor for CH3NH3PbI3 for photovoltaics. © 2018 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: 3,4‐Dihydroxybenzhydrazide (DHBH) could be considered a structural analogue of dopamine, forming polymers under oxidative conditions in a polydopamine (PDA) fashion. However, the former turns out to be more reluctant to oxidize and thus, more drastic conditions must be applied to achieve polymerization. Heating of DHBH in the presence of ammonium peroxydisulfate in Tris buffer yields a mixture of oligomers (average 9–10 monomer units). Although it looks black like PDA, its structure is very different. The polymer is not built up by CC bond formation but by replacement of hydroxyl groups resulting in acylhydrazine, acylhydrazone, and 1,3,4‐oxadiazoline bridging. Since the catechol moiety of the starting material is destroyed, the polymer lacks the mussel‐like anchoring property found in PDA. [ABSTRACT FROM AUTHOR]

Abstract: Earth‐abundant first‐row transition‐metal nanoclusters (NCs) have been extensively investigated as catalysts. However, their catalytic activity is relatively low compared with noble metal NCs. Enhanced catalytic activity of cobalt NCs can be achieved by encapsulating Co NCs in soluble porous coordination cages (PCCs). Two cages, PCC‐2a and 2b, possess almost identical cavity in shape and size, while PCC‐2a has five times more net charges than PCC‐2b. Co2+ cations were accumulated in PCC‐2a and reduced to ultra‐small Co NCs in situ, while for PCC‐2b, only bulky Co particles were formed. As a result, Co NCs@PCC‐2a accomplished the highest catalytic activity in the hydrolysis of ammonium borane among all the first‐row transition‐metals NCs. Based on these results, it is envisioned that confining in the charged porous coordination cage could be a novel route for the synthesis of ultra‐small NCs with extraordinary properties. [ABSTRACT FROM AUTHOR]

Abstract: Streptococcosis is an important bacterial disease in Nile tilapia causing severe economic losses to tilapia aquaculture worldwide. The effects of water quality (low‐ [LS] and high‐level [HS] soiling, to mimic clean or dirty surface conditions and temperatures) and disinfectant application (diluted concentrations and exposure time) were characterized on the inactivation of Streptococcus agalactiae isolated from diseased tilapia. Five isolates were tested against three commercial disinfectant products with the main ingredients being povidone iodine (Anidine 100™; AD), benzalkonium chloride (Better BKC 80%™; BKC 80), and a mixture of quaternary ammonium compounds and glutaraldehyde (Chloraldehyde™; CR). CR demonstrated highest efficacy to S. agalactiae inactivation, followed by BKC 80 and AD, respectively. Higher‐level soiling, low temperature, diluted concentrations and short exposure time all decreased the disinfectant efficacy. CR and BKC 80 provided more than 5‐log inactivation at 1‐min exposure at 20°C under HS conditions, and also with ten‐fold‐diluted concentrations at 60‐min exposure time at 30°C. However, AD required 10‐min exposure to effectively remove bacteria under LS conditions at 30°C. The results could facilitate aquaculture management planning that leads to operating cost reductions and improvements in biosecurity. [ABSTRACT FROM AUTHOR]

Crosslinked hydroxyl-conductive copolymer/silica composite membranes based on addition-type polynorbornene, poly(dodoxymethylene norbornene-co-norbornene-3-(trimethylpropyl ammonium)-functionalized silica (QP(DNB/NB-SiO2), were prepared by a sol-gel method. Copolymer composite membranes with different degree of quaternary ammonium functional silica, designated as QP(DNB/NB-SiO2-X) ( X = 5, 10, 15 and 25 wt%, respectively), displayed good dimensional stabilities with low in-plane swelling rate of 1.32-3.7%, good mechanical properties with high elastic modulus of 605.4-756.8 MPa and high tensile strength of 13.2-20 Mpa. The achieved copolymer composite membranes could self-assemble into a microphase-separated morphology with randomly oriented long-range aliphatic chain/cylinder ionic channels that were imbedded in the hydrophobic PNB matrix. Among these membranes, the QP(DNB/NB-SiO2-25) showed the parameter with ionic conductivity of 9.33 × 10−3S cm−1, methanol permeability of 2.89 × 10−7cm2 s−1, and ion-exchange capacity(IEC) of 1.19 × 10−3 mol g−1. A current density of 82.3mA cm−2, the open circuit voltage of 0.65 V and a peek power density of 32 mW cm−2 were obtained. POLYM. ENG. SCI., 58:13-21, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Three ammonium-cationic zeolites (ferrierite, ZSM5, and zeolite BETA) are individually analyzed to produce branched-chain fatty acid (i.e., isostearic acid) from unsaturated linear-chain fatty acid (ulc-FA) with up to 98% conversion and 80% selectivity. The SiO2/Al2O3 molar ratio of zeolite, amount of water and choice of additive are found to be the key factors for the efficiency of zeolites in this particular reaction. Detailed characterization of zeolites supports the optimization parameters to produce the best results. Large scale production of isostearic acid achieving a 76% selectivity and 96% conversion demonstrates the potential of this system's capability at the pilot scale. Variation in isomeric composition of branched-chain fatty acid (bc-FA) product is observed for the three different catalytic methods. Dimer production due to interaction with the external acidic surface of these zeolites has been observed, but it can be suppressed. Practical Application: Lubricant, cosmetic and surfactant fields are examples where these biodegradable isostearic acid and other bc-FA materials are applied. Three ammonium cationic zeolites (i.e., ferrierite, BETA, ZSM-5) are used to produce the iso-oleic acid (precursor of isostearic acid) with high selectivity. The iso-oleic acid products are found to have different isomeric compositions which could potentially expand the application of the isostearic acid. [ABSTRACT FROM AUTHOR]

ABSTRACT To increase the encapsulation efficiency of microcapsules composed of water-soluble salt cores and hydrophobic material shells, we herein reported a facile and versatile strategy to improve the hydrophobicity of water-soluble salts [i.e., ammonium persulfate (APS)] by surface modification of APS using oleic acid or silane coupling agent, respectively. The results confirmed that the hydrophobicity of the two modified APS had been successfully improved compared with that of non-modified APS. Moreover, the two modified APS could be effectively encapsulated into hydrophobic polystyrene and the encapsulation efficiency of the resulting microcapsules goes up significantly. This study was expected to drive progress in the preparation technology of microcapsules which comprise water-soluble salts as cores and hydrophobic polymer materials as shells in many industrial application fields. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45294. [ABSTRACT FROM AUTHOR]

A study of the phase transitions occurring in tetramethylammonium hexachlorometalate compounds with M = UIV, NpIV, ZrIV, SnIV, HfIV, and PtIV were performed using singlecrystal X-ray diffraction across the temperature range 120-400 K. When the crystals are cooled, movement of the octahedral [MCl6]2- anions induces a phase transition from Fm3m to Fd3c with a doubling of the unit cell. For the actinide compounds, no correlation between the f-electron configuration and the transition temperature was observed; instead, a correlation between the transition temperatures and both the [MCl6]2- anion and the TMA cation size is highlighted. Two phase transitions were observed and characterized. The first phase transition occurs with the ordering of the TMA cation and the second from a rotation of the [MCl6]2- octahedra. A third phase transition was observed at lower temperatures and was ascribed to a tetragonal distortion of the [MCl6]2- anions. Synthesis and study of the deuterated compounds did not show a significant isotope effect. Raman spectra of the protonated and deuterated compounds indicate only weak hydrogen bonding interactions between the TMA cations and the [MCl6]2- octahedra. [ABSTRACT FROM AUTHOR]

The plant-availability of phosphorus (P) in fertilizers and soil can strongly influence the yield of agricultural crops. However, there are no methods to efficiently and satisfactorily analyze the plant-availability of P in sewage sludge-based P fertilizers except by undertaking time-consuming and complex pot or field experiments. We employed the diffusive gradients in thin films (DGT) technique to quantify the plant P availability of various types of P fertilizers with a novel focus on sewage sludge-based P fertilizers. Mixtures of fertilizer and soil were incubated for 3 weeks at 60% water holding capacity. DGT devices were deployed at the beginning of the incubation and again after 1, 2, and 3 weeks. Two weeks of incubation were sufficient for the formation of plant-available P in the fertilizer/soil mixtures. In a pot experiment, the DGT technique predicted maize ( Zea mays L.) biomass yield and P uptake significantly more accurately than standard chemical extraction tests for P fertilizers ( e.g., water, citric acid, and neutral ammonium citrate). Therefore, the DGT technique can be recommended as a reliable and robust method to screen the performance of different types of sewage sludge-based P fertilizers for maize cultivation minimizing the need for time-consuming and costly pot or field experiments. [ABSTRACT FROM AUTHOR]

Despite the rapid reaction rates and high efficiency of the radical-mediated thiol-ene reactions in high concentrations, complications arise when implementing this reaction under dilute conditions, such as those often requisite for polymer-polymer conjugation. Here, we briefly review some of the challenges inherent in polymer modification via thiol-ene reactions and demonstrate several successful polymer couplings (including star polymer assembly) under a variety of conditions with coupling efficiencies exceeding 91% achieved with appropriate initiator and terminal functional group selection. Generally, the results indicate thermal initiation with an 'azobis' initiator was unsuccessful in polymer-polymer conjugation of a thiol-terminated poly(ethylene glycol) (PEG) to an alkene terminated PEG. Reduction-oxidation initiators, both ammonium persulfate and Fe(II) and Fenton's reagent were effective in conjugating thiol terminated PEG to norbornene terminated PEG, but not to an allyl ether terminated PEG. Type I photoinitiators, in particular a water soluble acyl phosphinate, were more effective than either the examined thermal or redox initiators for thiol-ene polymer-polymer conjugations generally. [ABSTRACT FROM AUTHOR]

Ammonium polyphosphate (APP) and inorganic fillers were applied for improving flame retardancy and mechanical performance of recycled poly(ethylene terephthalate) (RPET). RPET was compounded with 5-10 wt% of talc and glass bead using twin screw extruder then were injection molded with 2 wt% of APP. The effects of fillers contents and APP on properties and flame retardancy of RPET composites were investigated. The incorporation of talc and glass bead as well as the adding of APP significantly improved tensile and flexural modulus of RPET composites. Scanning electron microscope micrographs indicated good distribution of talc, while glass bead was agglomerated on the RPET matrix. Flame-retardant property of neat RPET and the RPET composites revealed V-2 of UL-94 flammability rating. It can be noted that the composites were less dripping because of the synergistic effect of adding talc and glass bead with APP. From thermogravimetric analysis results, larger of residual char contents and lower values of the activation energy were considered for enhancing flame retardancy in the RPET composites. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ethanol is shown to act as a hydrogenating agent for ynamides under palladium catalysis. This behavior is different from the normally expected reaction of ethanol addition to alkynes. The reaction shows stereoselectivity for E enamides, which is in contrast to reports using other hydrogenating sources. The method was also extended to ynamines. Alternatively, the use of ethanol and ammonium formate as the hydrogenating source gives Z enamides. The role of ethanol in hydrogenation was demonstrated by means deuterium labeling experiment. [ABSTRACT FROM AUTHOR]

The effects of different n-alkanol co-surfactants on the size, shape, composition and dynamics of reverse micelles (RMs) in cetyltrimethylammonium bromide (CTAB)/n-alkanol/n-hexane/water and CTAB/n-alkanol/n-pentane/water microemulsions were investigated using T2 relaxation and pulsed gradient stimulated echo nuclear magnetic resonance (NMR) measurements and molecular modelling. NMR T2 relaxation times and diffusion coefficients were determined for the surfactant and co-surfactant in these CTAB quaternary reverse microemulsions, for a range of medium chain length alcohol co-surfactants, from 1-butanol to 1-heptanol. These data revealed a slight RM size dependency on co-surfactant chain length, with RM sizes tending to decrease with increasing alcohol chain length. Molecular modelling of CTAB/n-alkanol/n-hexane/water RMs suggested a variation in RM shape with co-surfactant chain length, where those formed with pentanol were found to be least spherical and those formed with heptanol the most spherical. The NMR data also revealed differences in the behaviour of the micellar structures in the CTAB/n-pentanol/n-hexane/water reverse microemulsion, compared with the other reverse microemulsions in this study, where CTAB was found to be distributed between two environments, which then combined to form larger micelles. The origins of these differences remain unclear. [ABSTRACT FROM AUTHOR]

A comprehensive investigation, utilizing valence-bond- and molecular-orbital-based techniques, reveals that C−N bonds in protonated and methylated ammonium compounds are charge shift bonds. Moreover, the ammonium compounds are predominantly covalent at equilibrium distance, yet have two competing dissociation channels, which determine whether or not a state function crossing occurs during dissociation. The location of the crossing point can be predicted with relative ionization potentials, and may be tuned by altering the stabilization of the respective fragments. By closely examining the nature of the C−N bond as it is stretched, a correlation is observed between the extent of the charge shift nature and bond length. Identification of charge shift bonds in these ubiquitous organic species specifically affects understanding of their role in organocatalysis, in which the C−N bond is stretched. [ABSTRACT FROM AUTHOR]

The N-H...O hydrogen bond is the characteristic interaction in the crystal structures of N-benzyl- P-phenyl- N′-( p-tolyl)phosphonic diamide, C20H21N2OP or (C6H5)P(O)(NHCH2C6H5)(NHC6H4- p-CH3), (I), diphenylphosphinic 1-methylpropylamide, C16H20NOP or (C6H5)2P(O)[NHCH(CH3)(C2H5)], (II), ( S)-1-phenylethylammonium N-[( S)-1-phenylethyl]phenylphosphonamidate, C8H12N+·C14H15NO2P− or [ S-(C6H5)CH(CH3)NH3][(C6H5)P(O){ S-NHCH(CH3)(C6H5)}(O)], (III), and (4-methylbenzyl)ammonium diphenylphosphinate, C8H12N+·C12H10O2P− or [4-CH3-C6H4CH2NH3][(C6H5)2P(O)(O)], (IV). This article focuses on the N-H...O hydrogen bonds by considering the structures of (I), (II), (III) and (IV), and reviewing their analogous compounds, including 43 (C)P(O)(N)2, 102 (C)2P(O)(N), 31 (C)P(O)(N)(O) and 96 (C)2P(O)(O) structures, deposited in the Cambridge Structural Database (CSD). For the structures with a (C)P(O)(N)2 segment, only neutral hydrogen bonds were found in the CSD. The other three classes of compounds included both neutral and `charge-assisted' hydrogen bonds, and the (C)2P(O)(O) structures were particularly noticeable for a high number of cation-anion compounds. The overall tendencies of N...O distances in neutral and cation-anion compounds were compared. The N-H...O hydrogen-bond angles were also analyzed for the four classes of phosphorus compounds. [ABSTRACT FROM AUTHOR]

The organic–inorganic hybrid compound 1,4-butyldiammonium hexaaquadicadmium(II) trisulfate (C4H14N2)[Cd2(H2O)6(SO4)3] (1) was synthesized by the reaction of 3CdSO4·8H2O with 1,4-butanediamine in sulfuric acid aqueous solution. Differential scanning calorimetry measurements indicate that 1 undergoes a reversible phase transition at 243.4 K with a thermal hysteresis of 3.3 K. Single-crystal X-ray diffraction data disclose that the phase transition is from the room-temperature phase with the space group C2/c to the low-temperature phase with the space group P1 with the Aizu notation of 2/mF1. The structural phase transition of 1 is ascribed to the coupling of disorder–order transformations of the flexible 1,4-butyldiammonium cation and a sulfate anion and reorientation of the cation. The temperature dependence of the dielectric permittivity demonstrates a step-like change in the range 200–260 K, which makes (C4H14N2)[Cd2(H2O)6(SO4)3] a promising switchable dielectric material. The results could offer an avenue to design switchable dielectric materials through the synergistic effect of disorder–order transitions and reorientation motion. [ABSTRACT FROM AUTHOR]

Eight types of cationic glycidyl triazole polymers (GTPs) are prepared from combinations of four quaternary ammonium cationic units (pyrrolidinium, piperidinium, morpholinium, and N, N-diethyl-substituted ammonium) and two N-alkyl substituents (methyl and ethyl groups). These poly(ionic liquid)s are prepared using Cu(I)-catalyzed azide-alkyne cycloaddition reaction between the alkyne derivatives of ionic liquids and glycidyl azide polymer. The ionic conductivity is characterized by impedance measurement. The ionic conductivity depends on the type of the cationic unit, but the type of the N-alkyl substituent shows little influence on the ionic conductivity. The order of the cationic units that afford high ionic conductivity is as follows: pyrrolidinium > N,N-diethyl-substituted ammonium > piperidinium > morpholinium. The highest anhydrous ionic conductivity obtained in this study is 9.8 × 10−6 S cm−1 at 30 °C for the GTPs with the 1-methylpyrrolidinium unit. Based on electrode polarization analysis, the conducting ion (carrier) concentration and mobility are calculated. [ABSTRACT FROM AUTHOR]

Self-supporting membranes built entirely of carbon nanotubes have been prepared by wet methods and characterized by Raman spectroscopy. The membranes are used as supports for the electrodeposition of Pt nanoparticles without the use of additional additives and/or stabilizers. The Pt precursor is an ad hoc synthesized ammonium-ethylimidazolium chloroplatinate(IV) salt, [NH3(CH2)2MIM)][PtCl6]. The Pt complex was characterized using NMR spectroscopy, XRD, ESI-MS, and FTIR spectroscopy. The interaction between the Pt-carbon nanotubes nanocomposites and hydrogen is analyzed using electrochemical and quartz microbalance measurements under near-ambient conditions. The contribution of the Pt phase to the hydrogen adsorption on nanotube is found and explained by a kinetic model that takes into account a spillover event. Such a phenomenon may be exploited conveniently for catalysis and electrocatalysis applications in which the hybrid systems could act as a hydrogen transfer agent in specific hydrogenation reactions. [ABSTRACT FROM AUTHOR]

The characteristics, performance and application of ion-selective electrodes for bromate ion based on rhodamine B and tetrahexyl ammonium bromide as electrode-active substances are described for the first time. These electrodes respond with sensitivities of (58.0±1.0) and (61.0±2.0) mV decade−1 over the range 1.0×10−8-1.0×10−2 mol l−1 at pH 4-9 and 4-8 and a detection limit of 6.0×10−8 and 4.0×10−8 mol l−1 for rhodamine B and tetrahexyl ammonium bromide sensors, respectively. The electrodes are easily constructed at a relatively low cost, have a fast response time and can be used for a period of 3 months without any considerable divergence in potential. The proposed sensors displayed good selectivity for bromate ion in the presence of several substances and inorganic anions. Sensors were used for the direct assay of bromate ion in drinking water samples. [ABSTRACT FROM AUTHOR]

ABSTRACT Synthesis and properties of anion conductive aromatic block copolymers, QPE-bl-3, QPE-bl-3 M2, and M4, containing fluorenylidene biphenylene groups as scaffold for ammonium groups are described. These copolymers share the same main chain structure, but the position and the number of ammonium groups on a fluorenyl group differ. High molecular weight quaternized block copolymers were obtained via typical chloromethylation reaction or using preaminated monomers, and were well-characterized by 1H NMR spectra. Self-standing bendable membranes were obtained by solution casting. QPE-bl-3 M4 membranes containing four ammonium groups per hydrophilic repeat unit (highest ammonium density) in the hydrophilic block exhibited well developed phase-separated morphology, while QPE-bl-3 membranes containing two ammonium groups per hydrophilic repeat unit exhibited high anion conductivity. The highest anion conductivity (104 mS/cm) was obtained with QPE-bl-3 membrane (IEC = 2.1 meq/g) at 80 °C in water. An H2/O2 alkaline fuel cell was operable with the membrane to achieve 62 mW/cm2 of the maximum power density at 161 mA/cm2 of the current density. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 935-944 [ABSTRACT FROM AUTHOR]

The effect of gemini (16- s-16, s = 4, 5, 6) surfactants on the reaction rate of ninhydrin with [Cu(II)-Gly-Tyr] complex was determined using a spectrophotometric technique. The ninhydrin concentration was kept in excess in order to maintain pseudo-first-order conditions. The reaction followed irreversible first- and fractional-order kinetics with respect to [Cu(II)-Gly-Tyr] and [ninhydrin], respectively. It is found that gemini surfactants effectively catalyze the reaction. The rate constants ( k) first increase and then become relatively constant with increasing gemini surfactant concentration similar to conventional cetyltrimethylammonium bromide. At higher gemini surfactant concentration a third region of increasing k is observed. The unusual third region is ascribed to changes in micellar morphology. The kinetic data has been analyzed using a micellar pseudo-phase model. [ABSTRACT FROM AUTHOR]

Anaerobic ammonium oxidation (anammox) widely occurs in marine ecosystems, and it plays an important role in the global nitrogen cycle. But in freshwater ecosystems its occurrence, distribution and contribution, especially in extreme environments, are still not well known. In this study, anammox process was investigated in some extreme environments of freshwater ecosystems, such as those with high (above 75°C) and low (below -35°C) temperature, high (pH > 8) and low (pH < 4) pH and eutrophy (the concentration of NH4+-N > 300 mg kg-1). The polymerase chain reaction (PCR) screening results showed that anammox bacteria were widespread in the examined sediments from freshwater extreme environments. Quantitative PCR showed that the abundance of anammox bacteria ranged from 6.94 × 104 to 8.05 × 106 hydrazine synthase (hzsB) gene copies g-1 dry soil. 15N-labelled incubation experiments indicated the occurrence of anammox in all examined sediments and the potential anammox rates ranged from 0.02 to 6.24 nmol N g-1 h-1, with a contribution of 3.45-58.74% of the total N2 production. In summary, these results demonstrate the occurrence of anammox in these extreme environments, inferring that anammox may harbour a wide ecological niche in the freshwater ecosystems. [ABSTRACT FROM AUTHOR]

A novel and regioselective ammonium iodide mediated C−S bond formation protocol involving flavones and sulfonyl chlorides to generate different ArS-substituted flavone derivatives in high yields was developed. Different from existing metal-free C−S bond formation protocols with the use of PPh3 or I2 as the catalyst, this method provides an alternative way of constructing C−S bonds through the use of NH4I as a catalyst, which makes it highly valuable for the efficient synthesis of thioether compounds. [ABSTRACT FROM AUTHOR]

By exploiting salt formation, a new series of primary ammonium monocarboxylate salts of a nonsteroidal anti-inflammatory drug, namely, diflunisal, was synthesized. The majority of the salts thus synthesized turned out to be good gelators of various solvents, including the solvents (e.g., methyl salicylate and pure water) typically used for topical gel formulation. Single-crystal X-ray diffraction studies of a few gelator and nongelator salts in the series revealed details of the hydrogen-bonding networks present in the salts. Furthermore, one such gelator salt, namely, the diflunisal salt of serinol, was found to be biocompatible (MTT assay), and its anti-inflammatory (PGE2 assay) response turned out to be as good as that of the parent drug, which is indicative of its potential in biomedical applications. [ABSTRACT FROM AUTHOR]

The rheological properties of aqueous systems composed of each of the four homologous cationic surfactants (3-alkoxy-2-hydroxypropyl trimethyl ammonium bromides, CHTAB, n = 12, 14, 16 and 18) in the presence of an anionic surfactant, sodium octanoate (SO), have been studied by using steady state and frequency sweep rheological measurements. The effects of surfactant concentration, hydrophobic chain length and temperature were investigated. In CHTAB solution, the viscosity shows shear thinning in the concentration range of C >320 mmol/kg. Addition of SO promotes the micellar growth and results in the generation of wormlike micelles. Zero-shear viscosity ( η) of the binary surfactant system exhibits a maximum point in the investigated concentration range, suggesting the interaction between CHTAB and SO molecules is strongest at the optimal ratio of CHTAB with SO. The decrease in viscosity was attributed to be the transition from entangled wormlike micelles to branching micelles after the maximum point, cryo-TEM images revealed the changes in the structure of the wormlike micelles. [ABSTRACT FROM AUTHOR]

Ordered hexagonal mesoporous aluminosilicate matrix (Al-MCM-41) with incorporated ammonium molybdophosphate (AMP) was successfully synthesized by a one-pot synthesis method with natural clay from low-grade potash ores of Qinghai salt lake as the silica and aluminum source. We introduced a modified 'liquid-phase transport' step, which allowed the use of impure natural clay as a starting material to directly produce pure product without sedimentation pretreatment. The resultant product was characterized by X-ray fluorescence (XRF) spectroscopy, FTIR spectroscopy, XRD, TEM, 27Al and 31P magic-angle spinning (MAS) NMR spectroscopy, and N2 adsorption/desorption, which indicated that the AMP was immobilized in the mesoporous structure of Al-MCM-41. The adsorption capacity of the final product for the removal of cesium ions in solution was also investigated. The results suggested that salt lake clay is a promising low-cost precursor for the production of mesoporous aluminosilicate supports through one-pot syntheses, and the final composite material is effective for the adsorption of cesium ions from solutions containing other alkali metal ions. [ABSTRACT FROM AUTHOR]

Two inclusion compounds of dithiobiurea and tetrapropylammonium and tetrabutylammonium are characterized and reported, namely tetrapropylammonium carbamothioyl(carbamothioylamino)azanide, C12H28N+·C2H5N4S2−, (1), and tetrabutylammonium carbamothioyl(carbamothioylamino)azanide, C16H36N+·C2H5N4S2−, (2). The results show that in (1), the dithiobiurea anion forms a dimer via N-H...N hydrogen bonds and the dimers are connected into wide hydrogen-bonded ribbons. The guest tetrapropylammonium cation changes its character to become the host molecule, generating pseudo-channels containing the aforementioned ribbons by C-H...S contacts, yielding the three-dimensional network structure. In comparison, in (2), the dithiobiurea anions are linked via N-H...S interactions, producing one-dimensional chains which pack to generate two-dimensional hydrogen-bonded layers. These layers accommodate the guest tetrabutylammonium cations, resulting in a sandwich-like layer structure with host-guest C-H...S contacts. [ABSTRACT FROM AUTHOR]

Chiral hold promise in many asymmetric applications. This study explores the impact of ionic solutes on the chiral discrimination of five amino acid methyl ester-based , including L- and D-alanine methyl ester, L-proline methyl ester, L-leucine methyl ester, and L-valine methyl ester cations combined with bis(trifluoromethanesulfonimide) anion. Circularly polarized luminescence spectroscopy was used to study the chiral discrimination by measuring the equilibrium of a dissymmetric europium complex, Eu(dpa)33− (where dpa = 2,6-pyridinedicarboxylate). The chiral discrimination measured was dependent on the concentration of Eu(dpa)33− and this concentration-dependence was different in each of the . with L-leucine methyl ester and L-valine methyl ester even switched enantiomeric preference based on the solute concentration. Changing the cation of the Eu(dpa)33− salt from tetrabutylammonium to tetramethylammonium ion also affected the chiral discrimination demonstrated by the . Chirality 27:320-325, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

N-Nitramino/N-oxyl functionalization strategies were employed to investigate structure-property relationships of energetic materials. Based on single-crystal diffraction data, π-π stacking of pyrazole backbones can be tailored effectively by energetic functionalities, thereby resulting in diversified energetic compounds. Among them, hydroxylammonium 4-amino-3,5-dinitro-1H-pyrazol-1-olate and dipotassium N,N′-(3,5-dinitro-1H-pyrazol-1,4-diyl)dinitramidate, with unique face-to-face π-π stacking, can be potentially used as a high-performance explosive and an energetic oxidizer, respectively. [ABSTRACT FROM AUTHOR]

The structures of two hydrated salts of 4-aminophenylarsonic acid ( p-arsanilic acid), namely ammonium 4-aminophenylarsonate monohydrate, NH4+·C6H7AsNO3−·H2O, (I), and the one-dimensional coordination polymer catena-poly[[(4-aminophenylarsonato-κ O)diaquasodium]-μ-aqua], [Na(C6H7AsNO3)(H2O)3] n, (II), have been determined. In the structure of the ammonium salt, (I), the ammonium cations, arsonate anions and water molecules interact through inter-species N-H...O and arsonate and water O-H...O hydrogen bonds, giving the common two-dimensional layers lying parallel to (010). These layers are extended into three dimensions through bridging hydrogen-bonding interactions involving the para-amine group acting both as a donor and an acceptor. In the structure of the sodium salt, (II), the Na+ cation is coordinated by five O-atom donors, one from a single monodentate arsonate ligand, two from monodentate water molecules and two from bridging water molecules, giving a very distorted square-pyramidal coordination environment. The water bridges generate one-dimensional chains extending along c and extensive interchain O-H...O and N-H...O hydrogen-bonding interactions link these chains, giving an overall three-dimensional structure. The two structures reported here are the first reported examples of salts of p-arsanilic acid. [ABSTRACT FROM AUTHOR]

A sulfonyl-containing ammonium-based Brønsted acid ionic liquid was prepared and used as a liquid heterogeneous catalyst for organic reactions. The unique macroscopic phase heterogeneity of the IL in the reaction system not only ensures an excellent catalytic activity of the IL catalyst but also avoids the use of organic reaction solvents. The catalyst system is applicable for a wide range of reactions. [ABSTRACT FROM AUTHOR]