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We describe a method for the differentiation of carboxylate anions on disposable paper supports (common printer paper, filter paper, chromatography paper), based on differential patterns of interactions between carboxylates and a fluorescent sensing system. The sensor was built from commercially available components, namely a polycationic fifth generation amine-terminated poly(amidoamine) dendrimer (PAMAM G5) and a small organic fluorophore (calcein) through non-covalent interactions. The assay’s physical dimensions were chosen to conform to the microwell plate standard so detection could be carried out on widely available plate reader instrumentation. The sensing complex was first deposited in spots on a paper support to prepare the sensor strip; a carboxylate solution was then loaded on each spot. Nuanced changes in fluorescence were associated with carboxylate binding to the PAMAM dendrimer, characteristic of the structure and affinity of each carboxylate. Such signal changes, interpreted through Linear Discriminant Analysis (LDA), contained enough information to recognize and successfully discriminate most anions in the panel. Among the substrates we tested, chromatography paper was the most promising. The relationship between the structure of the carboxylates and the patterns giving rise to their differentiation was also discussed. Finally, the long-term stability (“shelf life”) of the pre-assembled [calcein·dendrimer] sensing system was found to be excellent when deposited on paper support. [ABSTRACT FROM AUTHOR]

This paper describes a new option for integrated recovery and esterification of carboxylates produced by anaerobic digestion at a pH above the pK a . The carboxylates (acetate, propionate, butyrate, valerate and lactate) are recovered using a strong anion exchange resin in the bicarbonate form, and the resin is regenerated using a CO 2 -expanded alcohol technique, which allows for low chemicals consumption and direct esterification. Paper mill wastewater was used to study the effect of pH and the presence of other inorganic anions and cations on the adsorption and desorption with CO 2 -expanded methanol. Calcium, which is present in paper mill wastewater, can cause precipitation problems, especially at high pH. Esters yields ranged from 1.08 ± 0.04 mol methyl acetate/mol of acetate in to 0.57 ± 0.02 mol methyl valerate/mol of valerate in . [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a range of papers on various topics, such as photon upconversion, catalytic activity, structural diversity, and crystal stability. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document provides a list of papers and their authors, allowing library patrons to quickly identify articles of interest for their research. [Extracted from the article]

Papers and textiles that are treated with per- and polyfluoroalkyl substances (PFASs) are sources of human and environmental exposure. Data for individual PFASs, such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA), are not placed into the context of total fluorine for papers and textiles. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to quantify volatile and ionic PFASs, respectively, and the total oxidizable precursor (TOP) assay was used to quantify precursors that form perfluoroalkyl carboxylates. Molar sums of PFASs obtained by GC-MS, LC-MS/MS, and precursors were compared to total fluorine (nmol F/cm²) determined by particle-induced gamma ray emission (PIGE) spectroscopy, measured before and after extraction. Volatile and ionic PFASs and unknown precursors accounted for 0-2.2%, 0-0.41%, and 0.021-14%, respectively, of the total nmol F/ cm² determined by PIGE. After extraction, papers and textiles retained 64 ± 28% to 110 ± 30% of the original nmol F/cm² as determined by PIGE, indicating that the majority of fluorine remains associated with the papers and textiles. The sum of PFASs in the volatile, ionic, and precursor fraction, and total fluorine after extraction indicate that mass balance was achieved (within analytical error) of the initial total fluorine measured by PIGE. [ABSTRACT FROM AUTHOR]

Although functionalized carbon-based materials have been widely used as the supercapacitor electrodes, the optimum contents of the functional groups, the charge storage mechanisms, and the effects of electrolytes and operating temperature have not yet been clearly investigated. In this work, carboxylate-modified hollow carbon nanospheres (c-HCN) with different functional group contents synthesized by an oxidation process of carbon nanospheres with nitric acid were coated on flexible carbon fibre paper and used as the supercapacitor electrodes. An as-fabricated supercapacitor of the c-HCN with a finely tuned 6.2 atomic % of oxygen of the oxygen-containing groups in an ionic liquid electrolyte exhibits a specific capacitance of 390 F g −1 , a specific energy of 115 Wh kg −1 , and a maximum specific power of 13548 W kg −1 at 70 °C. The charge storage mechanism investigated is based on the chemical adsorption of the ionic liquid electrolyte on the c-HCN electrode. This process is highly reversible leading to high capacity retention. The supercapacitor in this work may be practically used in many high energy and power applications. [ABSTRACT FROM AUTHOR]

A novel 3D luminescent metal–organic framework (MOF) denoted as [Eu(BTA)0.5(H2BTA)0.5(H2O)]n (Cj-2) has been constructed from a π-conjugated ligand with a tetracarboxylate group, 1,2,4,5-benzenetetracarboxylic acid (BTA), via solvothermal synthesis. Structural analysis reveals that the Cj-2 framework is composed of tetranuclear secondary building units (SBUs) containing uncoordinated carbonyl groups which provide feasible recognition sites to interact with analytes. Cj-2 shows a trinodal (4,6,10)-connected 3D topological network consisting of tetranuclear SBUs. Cj-2 displays outstanding potential as a luminescent sensor for detecting o-NP and Cd2+ in DMF suspension, with remarkable sensitivity and selectivity through the luminescence quenching effect. Cj-2 displays excellent luminescence quenching behaviour in the presence of other competing interfering analytes and can be recycled at least four times for sensing o-NP and Cd2+. For Cd2+ ions, it is the host–guest interactions and for the nitroaromatic compounds, it is the competitive absorption of excitation energy and the electron transfer mechanism that are the probable mechanisms for such sensing processes. Moreover, visual fluorescent test papers based on Cj-2 were assembled and employed to selectively detect nitroaromatic compounds and metal ions. Based on the aforementioned results, Cj-2 can be considered as a potential luminescence sensor for detecting Cd2+ and o-NP. [ABSTRACT FROM AUTHOR]

Butler's Bader Award recognizes her research group's many significant contributions elucidating the bioinorganic chemistry of the marine environment, including the chemistry of siderophores and vanadium haloperoxidases. While vanadium is the second-most abundant transition metal ion in seawater, iron levels are extremely low over much of the world's ocean. The original version of this article was revised: In the original publication author name was incorrectly published as "Alison Butler" and this has been corrected as "Lawrence Que, Jr". [Extracted from the article]

The paper of van der Ent et al. (Plant Soil 485:247–257, 2023), published in the previous issue, reports the hyperaccumulation of rare earth elements (REE) in plant species from the Proteaceae for the first time. Indeed, the high REE accumulation in Proteaceae is not completely unexpected, given that the plants release large amounts of carboxylates to acquire phosphorus and micronutrients. However, it is somewhat questionable that the efficiency of element mobilization alone sufficiently explains the large variability in REE accumulation among different taxa of Proteaceae or other P-efficient species that typically show low concentrations of REE. Given that REE3+ share chemical similarities to Ca2+ but form stable complexes with ligands similar to Al3+, it is reasonable that uptake and accumulation of REE depend not solely on element mobility but also on the dynamics of element speciation governed by the formation, stability, and fate of carboxylate-REE-complexes in the rhizosheaths. The rationale behind this contention is that for elements with low mobility in soil, changes in chemical speciation may increase the availability only if the complex stabilities that depend on rhizosphere pH allow a breakdown during uptake. In this commentary, we explore the idea that REE accumulation depends on rhizosphere processes related to nutrient acquisition and element exclusion that overlap in time, space, and function depending on the composition of metal-chelating ligands released by plant roots in concert with rhizosphere pH. Based on data from greenhouse and field experiments, we propose a model where plants with a P-mining strategy (hyper)accumulate REE when rhizosphere pH is below a critical value shifting the REE speciation to available forms. [ABSTRACT FROM AUTHOR]

This paper presents a preliminary scientific investigation of pigments used by Martiros Sarian, a prominent Armenian artist known for his vibrant and evocative paintings. The study focuses on five of Sarian's paintings from different periods of his career, namely, Morning in Stavrino, Arabian Dancer, Caravan, Yerevan Zangu River, and Kirovakan, dated between 1909 and 1948. Non-destructive techniques, including micro-attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging and X-ray fluorescence (XRF), were employed to characterize the pigments in the samples extracted from these paintings. The results reveal the presence of various pigments, including ultramarine blue, cobalt blue, cobalt cerulean blue, viridian, emerald green, cobalt green, celadonite green, cadmium yellow, chrome yellow, Venetian red, yellow ochre, red ochre, lead white, zinc white, and calcium carbonate. Additionally, metal carboxylates and oxalates, degradation products associated with the paint layers, were observed and discussed. The findings contribute to a better understanding of Sarian's artistic technique and provide valuable insights for the conservation and restoration of his artworks. [ABSTRACT FROM AUTHOR]

• The state of art of research in protective coatings for metallic cultural heritage has been reviewed. • A wide selection of representative papers testing protective coatings has been summarized. • Data on substrate, application, weathering and examination procedures is presented. • This review is intended as a starting point for future studies and developments in metal protection. The study and development of protective coatings for metallic heritage is a topic of continuous research, with the main objective of ensuring the protection of the object for as long as possible. The limitations imposed by conservation and restoration criteria, together with the diversity of factors involved, make metal protection an unresolved subject. In addition to the nature of the protective coating, different factors can influence its effectiveness, which may mean that one type of protection performs well in a certain environment or on one type of metal and not on another. Therefore, the main objective of this work is to provide a comprehensive review of the coatings used in the conservation of metallic heritage from the last decades to the present day. Studies carried out on coatings of the different families according to their nature/composition (waxes, acrylic resins, nitrocellulose lacquers, fluoropolymers, carboxylates, organosilanes compounds and other coatings) have been reviewed, considering the substrate, application, weathering and examination. [ABSTRACT FROM AUTHOR]

The tetranuclear Cu2+/Ca2+/Ca2+/Cu2+ complex based on Malten ligand has been investigated as a platform for anion binding. Simple organic carboxylates and non‐steroidal anti‐inflammatory drugs (NSAIDs) have been tested, revealing the ability of the platform to bind them. The receiving platform hosts at least two guests in solution although a third anion can be bound, as suggested by X‐ray diffraction analysis. The addition of the anions is accompanied by a color change of the solution, making the system a colorimetric sensor for carboxylates (LOD values comprised between 3.6 and 20.7 ppm). A fluorescent system consisting of the 2‐(3‐oxido‐6‐oxoxanthen‐9‐yl)benzoate (fluorescein anion) linked to the tetranuclear platform has been also prepared and used in a chemosensing ensemble approach to signal the presence of the selected anions (Log K between 2.6 and 5.6 for the addition of two guests). The latter also works in a paper strip test, offering the chemosensor a possible practical application. [ABSTRACT FROM AUTHOR]

The ancient lacquer films excavated from Dongshan Han tomb M6 of the Western Han Dynasty in Taiyuan City, Shanxi, China, were found sensitive to pH variation. This paper aims to demonstrate the pH-dependent warping behaviors of the ancient lacquer film and discuss their mechanism. The samples were analyzed by surface analytical techniques including attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray photoelectron spectrometry. The results suggest that the outer layer of the lacquer film is more oxidized than the inner layer and contains more carboxylates, with calcium ions and possibly ammonium cations as counter ions. The carboxylates are speculated to be formed by oxidative cleavages in the urushiol side chains and hydrolysis of glycerides of drying oils. The shrinkage and swelling of the lacquer film can be regulated by the type of cations (H+, Ca2+, Na+) of carboxylates through hydrogen bonds, coordination bonds and static forces. Due to the higher content of carboxylates in the outer part, it shrinks more at low pH causing warping outward and swells more at high pH causing warping inward. This paper may provide an important reference for pH control and help resolve the warping problem during conservation or restoration of ancient lacquerware. [ABSTRACT FROM AUTHOR]

A new method for the efficient conversion of pyridine methanols and ethyl carboxylates to pyridine esters in air catalyzed by Novozym 435 (N435) was reported. The enzyme catalyzed transesterification reaction was performed under the optimum conditions: N435 (60 mg) as a biocatalyst, acetonitrile (2.5 mL) as a solvent, the molar ratio of pyridine methanols (0.2 mmol) to ethyl carboxylats (1.0 mmol) of 1 : 5, molecular sieve 3 A of 1.00 g, reaction temperature of 50 °C, the revolution speed of 150 rpm and reaction time of 36 h. The enzyme still retained a yield of 80 % after repeated use for 10 times. Under optimal conditions, eighteen pyridine esters were synthesized in this paper, containing fifteen esters as novel compounds. The synthesized pyridine esters were analyzed by gas chromatography‐mass spectrometry‐olfactory (GC‐MS‐O), of which four pyridyl esters including compounds 3 a, 3 c, 3 g and 3 r possessed strong aromas which were based on peak area in GC‐MS. Thermogravimetric analysis (TG) was performed on these four flavor compounds. According to the results of TG analysis, they had good thermal stability at the certain temperature. [ABSTRACT FROM AUTHOR]

Although hydrogen-bonded organic frameworks (HOFs) have received particular attention in the field of proton conduction owing to their richly H-bonded networks and porous structures, there are few related reports, especially on the study of the related proton exchange membranes (PEMs). In this paper, a multi-pyridine and multi-carboxylate-based HOF (H3tpt = 4-(2,4,6-tricarboxyphenyl)-2,2′,6′,2′′-terpyridine, namely HOF 1) was successfully prepared and introduced in a chitosan (CS) matrix to fabricate proton-conductive composite membranes. Firstly, the excellent thermal-, water-, and acid-stability of HOF 1 were confirmed via various measurements. Secondly, an AC impedance test demonstrated its temperature- and humidity-dependent proton-conductive properties. Based on the above preliminary research, we tried to dope it into CS to prepare a composite membrane (denoted as CS/HOF-x , where x is the doping amount of 1 in the hybrid film). Fortunately, one composite membrane (CS/HOF-4) with ultra-high proton conductivity (σ) (2.61 × 10−2 S cm−1 under 100 °C and 98% RH) was fabricated using the casting method; its best σ value is 54 and 2 times greater than that of HOF 1 (4.83 × 10−4 S cm−1) and the pure CS membrane, respectively, and is comparable to that of Nafion under similar conditions. Further, the proton conduction mechanism of the HOF 1 composite membrane was proposed. This research represents the first time that HOF has been doped into CS to make a high-efficiency proton-conducting composite membrane, which will lay a good foundation for its application in fuel cells and other related fields. [ABSTRACT FROM AUTHOR]

• Four new d10 piperazine-bridged-amide-based coordination polymers were structurally directed by metal and carboxylate. • The title complexes can be acted as fluorescent sensors for nitrophenol and nitroaniline with low LOD, high K sv , good anti-interference and recyclable characteristics. • The feasibility of actual sample detection was verified by tap water, river water and wastewater samples. • The visual detection cloth and test paper were also prepared by solid phase deposition method and displayed good practical applicability. Four piperazine-amide-bridged d10 metal-organic coordination polymers, namely, [Zn(L) 0.5 (1,3-BDC)∙H 2 O]∙H 2 O (1), [Cd(L)(1,3-BDC)] (2), [Zn(L) 0.5 (5-MIP) ∙H 2 O]·H 2 O (3), [Cd(L)(5-MIP)] (4) were synthesized by the L ligand [N, N'-bis[(3-pyridin)acrylophenone] piperazine (L)] and two carboxylic acids with Zn/Cd(II) chloride under hydrothermal conditions. The title complexes were characterized by IR spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. Complex 1 is a 1D ladder-like structure. Complex 2 is a 3D NaCl type framework. Complexes 3 and 4 are 63 and 44 connected 2D structures. The different structural details of the title complexes directed by caroxylates and the central metals were compared. The complexes 1 – 4 can be used as excellent fluorescent sensors toward nitrophenol (NOP) and nitroaniline (NA) with a low limit of detection and a high quenching constant, and have good anti-interference and recyclable characteristics. The feasibility of actual sample detection was verified by tap water, river water and wastewater samples. Taking complex 3 as an example, the mechanism was also explored by fluorescence lifetime experiment and the UV-visible absorption spectroscopy. The 3 -modified visual detection cloth and test paper were also prepared by solid phase deposition method. Four new piperazine-amide-bridged metal-organic coordination polymers were obtained and used as fluorescent sensors for the detection of nitrophenol and nitroaniline in tap water, river water and wastewater environments. The sensors shows good recyclability, stability and low detection limit. The title-complex-modified detection cloth and test paper were prepared by solid phase deposition method to realize visual detection devices. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, gradient and block polycarboxylate ether superplasticizers (PCEs) composed of allyl alcohol polyoxyethylene ether macromonomer and acrylic acid were synthesized via aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization. The molecular structure of PCEs was characterized by 1H nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, and size exclusion chromatography (SEC), and the fluidity of cement paste and the influence of SO42− on the dispersibility of PCEs were investigated in detail. The experimental results show that the molecular weight and polydispersity of the obtained PCEs were well controlled by the RAFT process. Compared with the PCEs prepared by conventional free radical polymerization, the gradient PCEs synthesized by RAFT polymerization exhibited excellent dispersion capability. The range of molecular weights and acid-ether ratios of the gradient PCEs for high fluidity of cement paste was much wider. Furthermore, PCEs with gradient structure also showed excellent sulfate resistance. In contrast, PCEs with block architecture exhibited the lowest flowability. Based on these findings, the relationship between dispersibility of PCEs and their chemical structures was illustrated. [ABSTRACT FROM AUTHOR]

The micellar shape of octyl ether octaethylene oxide carboxylic acid ([H+][C 8 E 8 c−]) is restricted to spheres. A classical core–shell micellar regime (L 1) at lower surfactant concentrations transitions into a regime of head-group interdigitated micelles (L 1 ′) at higher concentrations. In the surfactant's sodium or calcium salts the micelles are deformed from spherical to slightly prolate spheroidal. The formation of a hexagonal (H 1) phase within the transition regime between L 1 and L 1 ′ is possible by a reduction of the area per molecule by counterion bridging. An increase in temperature decreases the influence of ion bridging and 'melts' the H 1 phase into a nematic phase (N) consisting of shorter chains of prolate micelles with a preferential orientation (grey arrow). [Display omitted] In a recent paper, we determined the phase behavior of an aqueous solution of octyl ether octaethylene oxide carboxylic acid ([H+][C8E8c−], Akypo™ LF2) and with partial replacement of H+ by Na+ and Ca2+. It was found that even the neat surfactants are liquid at room temperature and that they form only direct micelles for any aqueous content and over large temperature ranges. The aim of the present work was to find an explanation for the clouding in these systems as well as for the coacervation observed at very low surfactant content. We expected that very similar phase diagrams would be found for a full replacement of H+ by the mentioned ions. We established the respective phase diagrams of the above-mentioned salts in water and determined the structures of the occurring phases in detail with small-and wide-angle X-ray scattering, small-angle neutron scattering, dynamic light scattering, heat flux differential scanning calorimetry, as well as surface tension, ESI-MS, and NMR experiments. To our surprise, we discovered a new type of nematic phase between an isotropic and a hexagonal phase. Based on the complete description of all occurring phases both in the acidic and the charged surfactant systems, we were able to design a coherent and unified picture of all these phases, including the auto-coacervation at low surfactant concentration, the non-conventional clouding at high temperatures, the unusual liquid crystalline phases in a small domain at high surfactant concentrations, and the L β phase at low temperatures and at very low water content. It turned out that all phenomena are a consequence of the subtle interplay between a) the packing constraint due to the very large head-group, b) the relatively small hydrocarbon chain and c) the tunable electrostatic interactions versus entropy. [ABSTRACT FROM AUTHOR]

Solar-driven evaporation as a sustainable water purification technology exhibits great potential in solving the global water crisis. In this paper, a novel solar evaporator was successfully prepared with the reduced graphene oxide (rGO) and silver (Ag) nanowires as photothermal conversion media which were loaded into the sodium alginate (SA) hydrogel. It was found that the evaporation rate of the prepared evaporator reached 2.02 kg m−2 h−1 and the solar energy efficiency was 91% under one sun irradiation intensity. Furthermore, this novel solar evaporator exhibited expectant evaporation performance in the treatment of seawater and heavy metal sewage with excellent ion removal ability, with the removal efficiency of various ions higher than 99.9%. The ion-crosslinked SA hydrogel contained in the evaporator ensured the rejection of multivalent ions based on the distribution of carboxylate anions, and the three-dimensional porous channel of the super-hydrophilic hydrogel provided the convenient path for the transport of water molecules and the escape of water vapor. The binary composition of rGO and silver nanowires enhanced the photothermal conversion and the thermal conductivity, which was beneficial to the stable supply of thermal energy for evaporation. The purpose of this paper is to provide reference for promoting the practical application of solar evaporation. [ABSTRACT FROM AUTHOR]

Saponification, resulting from pigment–binder interactions, is one of the most endangering phenomena affecting the appearance and stability of painted works of art. The crystallization of metal carboxylates (soaps) in paint layers is recently assumed as the most critical point for the development of undesirable changes induced by saponification, however, the factors triggering it are not fully understood. The red pigment cinnabar (HgS) has been suspected of contributing to saponification, however, the paucity of reliable reference structural data limited the experimental research of its effect at the molecular level. Within this study we synthesized mercury(II) carboxylates of the formula Hg(C16)x(C18)2−x (x = 0.0; 0.2; 0.5; 0.8; 1.0; 1.2; 1.5; 1.8; 2.0) where C16 and C18 are hexadecanoate (palmitate) and octadecanoate (stearate), respectively, and characterize them by combination of X-ray powder diffraction (XRPD) and 13C and 199Hg solid state NMR (ssNMR). For a more detailed interpretation of their structural and thermal behavior, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used. The crystal structure of the studied mercury carboxylates was described on the basis of complementary ssNMR and XRPD measurements, Rietveld refinement and DFT calculations. All the subjected compounds crystallize in a monoclinic lattice of the C2/c symmetry. Mercury atoms are arranged in a slightly distorted square antiprismatic geometry and are monodentatically bonded to carboxylate anions. The structural disorder at the aliphatic end of the stearic acid chains was detected in the mixed carboxylates. Within the paper, the structural (dis)similarity with the corresponding lead carboxylates is discussed. The synthesized and characterized mercury carboxylates were applied to describe neo-formed mercury soaps in a model experiment simulating an egg-based paint system. [ABSTRACT FROM AUTHOR]

The combination of nanoparticles and polycarboxylate ether superplasticizers is expected to simultaneously improve the durability and mechanical properties of mortar and concrete. However, the uniform dispersion of nanoparticles in cement materials has always been a difficult challenge. In this paper, nanoparticles are modified with surfactants to provide a research direction for better dispersion of nanoparticles in cementitious materials. Modified allyl ether polycarboxylate superplasticizer with short-branched chains was synthesized from acrylic acid and allyl glycidyl ether. Nano-silica/polycarboxylate ether was obtained by grafting nano-silica onto polycarboxylate ether molecular chains through intermolecular dehydration, thus achieving a homogeneous dispersion of nano-silica in the cementitious material. The results show that nano-silica/polycarboxylate ether has better dispersibility in cement matrix and strong clay resistance, which compensates for the poor dispersion of polycarboxylate ether synthesized from conventional polyethylene glycol graft chains in the presence of clay impurities. [ABSTRACT FROM AUTHOR]

Abstract—In this paper, the possibility of enhancement of protective action of sodium oleate (SOl) toward Mg90 magnesium alloy is studied through its combined use with following sodium salts: oleyl sarcosine (SOs), mixture of alkenylsuccinic acids (SASA), and flufenamic acid (SFF). It is determined that introduction of 8 mM of most of the blends to the borate solution with 1 mM NaCl results in more effective inhibition of local depassivation of Mg90 than SOl at the same concentration. The highest anti-pitting basis is achieved upon addition of equimolar composition of SOl and SFF (2.40 V). By recording anodic polarization curves and tests in the humid atmosphere, the protection ability of the adsorption layers formed from aqueous solutions of 16 mM inhibitors and their blends is evaluated. It is shown that surface modification in SOl solutions with SFF and particularly SOs leads to a slight increase in protection, which depends significantly on the molar ratio of the components. A higher degree of protection is provided by the blends of SOl with SASA. The mixture of 12 mM SOl + 4 mM SASA is the most effective among them. Treatment in such solution with subsequent drying at 65°C significantly slows down corrosion even under severe conditions of periodic condensation of moisture on the specimens. [ABSTRACT FROM AUTHOR]

Graphical abstract This paper describes a new solvothermal strategy for controlling the size and crystal phase of iron oxide nanocrystals. Decreasing the chain length of aliphatic carboxylate precursors produces smaller nanocrystals and tuning the concentration of water in the solvent enables controlled formation of the hematite or maghemite phases of iron(III) oxide. Abstract This paper describes a new method for controlling nanocrystal size and crystal phase in solvothermal syntheses of iron oxide nanocrystals by altering the carbon chain length of aliphatic iron(III) carboxylate precursors and reaction solvent composition, respectively. Hematite (α-Fe 2 O 3) nanocrystals were synthesized from iron(III) carboxylate precursors in a 2:1 water:ethanol mixture in the presence of free aliphatic carboxylic acids or aliphatic primary amine ligands. In the presence of amine, increasing the length of the carbon chain of the iron(III) carboxylate precursor from two to eighteen carbons produced pseudocubic nanocrystals with size dispersities of ∼10% and diameters that decreased from 65 nm to 25 nm. Changing the chain length of the amine does not affect the size of the nanocrystals. In contrast, free carboxylic acid ligands produce polydisperse, polycrystalline hematite nanoparticles. The crystal structure of the iron oxide nanocrystals synthesized by this method depends on the mole-fraction of water (x water) in the water/ethanol solvent mixture: x water = 0 produces maghemite (γ-Fe 2 O 3), x water = 0.67 produces hematite, and x water = 1 produces a mixture of goethite (α-FeOOH) and hematite. The dependence of the nanocrystal size on ligand chain length is attributed to decreasing solubility of partially hydrolyzed iron(III) carboxylate precursors in the reaction solvent mixture with increasing chain length. The dependence of nanocrystal phase on solvent composition is attributed to the different reactivities of water and ethanol toward hydrolysis of the iron(III) carboxylate precursors. [ABSTRACT FROM AUTHOR]

• The single and binary adsorption of amoxicillin and doripenem on HKUST-1 was evaluated. • Interpretation of the single and binary adsorption mechanisms at different temperatures. • Description the competitive effect via statistical physics model. • Simulation of the adsorption process via DFT. The adsorption of amoxicillin (AMX) and doripenem (DRPNM) on copper benzene-1,3,5-tricarboxylate (HKUST-1) in single and binary systems is analyzed in this paper. The experimental results showed that the adsorption capacities of this MOF for the removal of these pharmaceuticals reduced from single to binary solutions. A monolayer adsorption model and its extended competitive version were successfully applied to analyze the adsorption data. The modeling results showed that the reduction of AMX and DRPNM adsorption capacities was explained by a competitive effect of these adsorbates generating an antagonistic behavior for both molecules where the same adsorption site was involved during their removal. The statistical physics model was also utilized to estimate the AMX and DRPNM adsorption orientation on the HKUST-1 surface. Adsorption energies were calculated confirming an exothermic removal process for both molecules and DFT simulations allowed to determine the role of hydrogen bonding in the adsorption mechanism. It was concluded that the interactions for the adsorption of DRPNM on this MOF were higher than those for AMX removal. Particularly, the oxygens linked to the cupper ions on MOFs structure played a crucial role during the adsorption mechanisms of these organic compounds. Overall, this paper presents a combination between experiment results and two different theoretical approaches to provide a new explanation of the mechanism of adsorption of two relevant antibiotics on HKUST-1 MOF. [ABSTRACT FROM AUTHOR]

Superplasticizers are widely used in the backfill industry for the improvement of the flow ability of cemented paste backfill (CPB) while keeping water content low. However, the coupled effects of temperature and curing time on the mechanical strength of CPB with superplasticizers are poorly understood. This paper presents new findings of research conducted to experimentally assess the effects of a polycarboxylate-based superplasticizer on the strength of CPB subjected to varying curing time (1, 3, 7, and 28 days) and temperature (2 °C, 20 °C, and 35 °C). The binders used were Portland cement type I, fly ash, and blast furnace slag. Superplasticizer contents of 0, 0.125, and 0.25 percent of the total weight of the CPB were added. Various microstructural analyses and monitoring programs were also conducted to understand the principles behind the patterns in the strength of different CPB samples. The results obtained show that the unconfined compressive strength (UCS) of the CPB containing polycarboxylate-based superplasticizer increases with time. Moreover, the increase in superplasticizer content was observed to improve the UCS of the CPB (0.25% > 0.125% > 0%). The temperature was also observed to play an important role in strength development as the UCS increases with the rise in the curing temperature for all samples. It is also found that the temperature-induced strength increase is more significant for the CPBs that contain the superplasticizer than for those without superplasticizer. It was also observed that the CPB containing superplasticizer maintained a relatively similar strength upon replacing the cement with 50% slag while showing a sharp decline with fly ash. The findings from this study will be useful towards a cost-effective design of backfill structures. [ABSTRACT FROM AUTHOR]

A commercial interest in the improvement of durability is driving efforts to develop new generation of surface-treatment agents. In the previous paper, a series of nanoSiO 2 -polycarboxylate superplasticizer core-shell nanoparticles (NS@PCE) were synthesized by “grafting to” method. In this paper, we aim to explore the potential of NS@PCE to densify the surface of cementitious materials, and to study the mechanism of nanoparticles surface-treatment process by measuring water absorption ratio, dispersion stability, pozzolanic reactivity, and mercury intrusion porosimetry. Results show that NS@PCE is effective in reducing the water absorption. Various NS@PCE present different influences, it seems that NS@PCE with a moderate shell-core ratio is a more reasonable choice. A hypothesis was proposed to explain the surface-treatment effect of nanoparticles, it utilizes two properties (dispersity and pozzolanic reactivity) of nanoparticles to describe their refining-pore performance. This research indicates a new pathway for nanoSiO 2 to optimizing cementitious materials. [ABSTRACT FROM AUTHOR]

Coordination polymers (CPs) in recent times have emerged as active constituents in many semiconductor devices like light emitting diodes (LED), field effect transistors (FET), photovoltaic devices and Schottky barrier diodes. An intelligent choice of linkers, careful selection of metal ions and post synthetic modification (PSM) can provide a better pathway for charge transportation. However, a proper understanding of the charge transport mechanism in CPs is still inadequate due to the lack of considerable experimental and theoretical work. In this paper, we address the theoretical elucidation of semiconducting properties and a probable pathway for charge transportation in three of our previously published CPs using density functional theory (DFT). These results help us to recognize the orbitals that have major contributions in the formation of the valence band and also provide the most likely pathway for optimum electronic communication. In this regard, the role of hydrogen bonding and unpaired electrons of metal d-orbitals is also established. [ABSTRACT FROM AUTHOR]

Coordination bonding of Ni(II) tetraazamacrocyclic (TAMC) complexes to carboxylic groups of organic polymers and graphene oxide paper (GOP) is proposed for a facile generation of paramagnetic centers by combining two diamagnetic components. The coordination functionalization occurs under basic conditions in water solution at room temperature. The coordination configuration of central Ni(II) changes from tetracoordinated square-planar to hexacoordinated pseudooctahedral, which implies the conversion from low-spin to high-spin nickel centers. In the case of organic polymers, the coordination bonding of Ni(II) macrocycles gives rise to characteristic changes in coloration (from yellow-orange to violet-blue), as well as clearly manifests itself in UV–visible, FTIR and EPR spectra. In the case of GOP, in addition to evident changes in FTIR spectra, morphological alterations in the mat surface and an increase in the mat thickness are observed in SEM images, which can be explained by an intercalating effect of voluminous macrocyclic cations, as well as by partial disintegration of GOP structure due to the liquid-phase treatment. The effective magnetic moments of tetraazamacrocycles attached to organic polymers vary from 0.88 to 1.47 BM, whereas for GOP considerably higher values of 2.10 and 2.87 BM were obtained. [ABSTRACT FROM AUTHOR]

In this paper, three isostructural 1D lanthanide complexes, [Ln(dppc)(H2O)4]n·2nH2O (Ln = Eu, Tb and Eu0.501Tb0.499, named 1-Eu, 2-Tb and Eu0.501Tb0.499), based on 3-(2,4-dicarboxylate phenyl)-2-pyridinecarboxylic acid (H3dppc) have been synthesized and characterized by elemental analysis, IR, PXRD, TG and X-ray crystallography. The complexes exhibit a 1D chain structure, which is further linked into a 3D supramolecular framework by hydrogen bonds. Tuneable emission colour of Eu0.501Tb0.499 is realized by adjusting the excitation wavelength. The sensing properties of 1-Eu and 2-Tb towards Fe3+ and aniline indicate that the two complexes have almost the same superior sensitivity and low detection limit for Fe3+ in aqueous solution, while they have different detection abilities for aniline in DMF solvent. The different detection abilities were discussed by means of PXRD, UV-vis, luminescence lifetimes and molecular surface calculations (Hirshfeld surface analysis and 2D fingerprint plots). [ABSTRACT FROM AUTHOR]

The Zr‐based metal–organic framework, Zr‐bzpdc‐MOF, contains the photoreactive linker molecule benzophenone‐4,4′‐dicarboxylate (bzpdc) which imparts the possibility for photochemical post‐synthetic modification. Upon irradiation with UV light, the keto group of the benzophenone moiety will react with nearly every C−H bond‐containing molecule. Within this paper, we further explore the photochemical reactivity of the Zr‐bzpdc‐MOF, especially with regard to which restrictions govern internal versus external reactions. We show that apart from reactions with C−H bond‐containing molecules, the MOF reacts also with water. By studying the reactivity versus linear alcohols we find a clear delineation in that shorter alcohol molecules (up to butanol as a borderline case) react with photoexcited keto groups throughout the whole crystals whereas longer ones react only with surface‐standing keto groups. In addition, we show that with the alkanes n‐butane to n‐octane, the reaction is restricted to the outer surface. We hypothesize that the reactivity of the Zr‐bzpdc‐MOF versus different reagents depends on the accessibility of the pore system which in turn depends mainly on the size of the reagents and on their polarity. The possibility to direct the post‐synthetic modification of the Zr‐bzpdc‐MOF (selective modification of the whole pore system versus surface modification) gives additional degrees of freedom in the design of this metal–organic framework for shaping and for applications. [ABSTRACT FROM AUTHOR]

In this paper, a series of methyltriphenylphosphonium carboxylate room temperature ionic liquids [Ph3PCH3][CnH2n+1COO] with different alkyl chain length (n = 7, 9, 11, 13, 15, 17) have been synthesized by quaternization of triphenylphosphine (TPP) with dimethyl carbonate (DMC) and followed anion exchange with different carboxylic acids. The synthesis route is not only simple, but also can avoid problems such as toxicity, environmental pollution and equipment corrosion. The structures of these compounds were characterized by FT-IR and 1H-NMR. Meanwhile, their surface adsorption and aggregation behavior in aqueous solution have been investigated by equilibrium surface tension, electrical conductivity and transmission electron microscopy (TEM) measurements. Furthermore, the impact of alkyl chain length on their surface adsorption and aggregation behavior were also investigated. TEM results indicated that methyltriphenylphosphonium carboxylate ionic liquid surfactants could self-assemble into regular spherical aggregates in aqueous solution. The diameter of the spherical aggregates is about 50 ∼ 100 nanometers and does not change much with the change of alkyl chain length. [ABSTRACT FROM AUTHOR]

This paper describes acid-catalysed reactions of 5,7-dimethoxy-1-methylindole and methyl 5,7-dimethoxyindole- 2-carboxylate with a range of aldehydes and ketones. The former indole reacts selectively at C3, whereas the latter reacts preferentially at C4 but also at C3 depending on the reaction conditions. Reactions of indoles with 2,2-dimethoxypropane and triethyl orthoformate are also reported. A range of di- and triindolylmethanes are described, together with an indolo-triptycene of novel structure. [ABSTRACT FROM AUTHOR]

• One Zn-MOF based an amide-containing carboxylic acid can selectively and sensitively detect biomarker (2-methoxyethoxy)acetic acid (MEAA) and antibiotic tetracycline hydrochloride (TC) through luminescence quenching. • The luminescence quenching was due to the weak interaction, competitive absorption and PET effect. • The potential application as luminescence test papers and detection experiment in simulated urine system indicated acceptable reliability for monitoring two analytes in real samples. One Zn-MOF, namely, {[Zn(L) 0.5 (bpy) 0.5 (H 2 O)]·H 2 O·DMF} n (LCU-123), was synthesized from an amide-containing carboxylic acid N,N"-(3,5-dicarboxylphenyl)benzene-1,4-dicarbox-amide (H 4 L) and 4,4'-bipyridine. The carboxylate ligand and 4,4'-bipyridine connect Zn(II) centers to form two-dimensional layers. Adjacent 2D layers are stacked to form a stable supramolecular structure with one-dimensional channels. Luminescence measurements indicated that the complex exhibited excellent multiple sensing activities toward biomarker (2-methoxyethoxy)acetic acid (MEAA) and antibiotic tetracycline hydrochloride (TC). It is worth noting that the LOD for MEAA and TC were as low as 18.030 and 0.552 μ M, respectively. Investigations on the sensing mechanism indicated that the luminescence quenching of MEAA was due to the weak interaction and dynamic quenching mechanism, while the quenching sensing of TC was attributed to competitive absorption and PET effect. The recoveries for the sensing analytes are satisfactory from 102.8 to 109.8% (toward MEAA in simulated urine) and 99.3 to 106.0% (toward TC in water), indicating the complex possesses acceptable reliability for monitoring the above two analytes in real samples. [Display omitted] [ABSTRACT FROM AUTHOR]

Self-powered sensors that do not require external power sources are crucial for next-generation wearable electronics. As environment-friendly ionic thermoelectric hydrogels can continuously convert the low-grade heat of human skin into electricity, they can be used in intelligent human-computer interaction applications. However, their low thermoelectric output power, cycling stability, and sensitivity limit their practical applications. This paper reports a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized carboxylated bacterial cellulose (TOBC) coordination double-network ionic thermoelectric hydrogel with lithium bis(trifluoromethane) sulfonimide (LiTFSI) as an ion provider for thermodiffusion, as LiTFSI exhibits excellent thermoelectric properties with a maximum power output of up to 538 nW at a temperature difference of 20 K. The interactions between the ions and the hydrogel matrix promote the selective transport of conducting ionic ions, producing a high Seebeck coefficient of 11.53 mV K−1. Hydrogen bonding within the polyacrylamide (PAAm) network and interactions within the borate ester bond within the TOBC confer excellent mechanical properties to the hydrogel such that the stress value at a tensile deformation of 3100 % is reaches 0.85 MPa. The combination of the high ionic thermovoltage and excellent mechanical properties ionic thermoelectric hydrogels provides an effective solution for the design and application of self-powered sensors based on hydrogels. [Display omitted] • The coordination of Carboxylated bacterial cellulose enhances the mechanical property of the PAAm matrix. • The output power of the ionic thermoelectric hydrogel at a temperature difference of 20 K is up to 538 nW. • The hydrogel based sensor can directly harvest the human body heat and generate a thermovoltage to drive the sensor. • Stability, sensitive human motion detection system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Portable mid-FTIR spectroscopy are used as diagnostic tool for identification of lead carboxylates. • Kinetics of lead carboxylates formation on mock-ups by ATR-FTIR and portable mid-FTIR are analysed. • The aging processes of the hydrocerussite and cerussite on the formation of lead carbosylates on paintings are investigated. • Lead azelate is identified by portable mid-FTIR spectroscopy. This paper demonstrates the efficacy of portable mid-infrared spectroscopy as a diagnostic tool for revealing the presence of lead carboxylates on artworks, in situ , without sampling. Samples of cerussite and hydrocerussite - the main components of lead white - were separately mixed with linseed oil, and artificially aged in two steps. Their compositional changes have been monitored over time by infrared spectroscopy in two investigation modes: absorption (benchtop instrument) and reflection (portable instrument), and by XRD spectroscopy. Each component of lead white showed different behavior depending on aging conditions, giving important information about the degradation products which are found in real cases. The accordance of results obtained in both modalities demonstrates that portable FT-MIR is a reliable technique for individuating and identifying lead carboxylates directly on paintings. Examples of the efficacy of this application are provided, by studying paintings from the 17th and 18th centuries. [ABSTRACT FROM AUTHOR]

Two novel luminescent Cd(II)–organic frameworks, [Cd2(2-abpt)(Hbtca)(H2btca)0.5(H2O)]n (1) and {[Cd3(2-abpt)(btca)1.5]·H2O}n (2) (2-abpt = 3,5-di(2 -pyridyl)-4-amino-1,2,4-triazole, H4btca = 1,2,4,5-benzenetetracarboxylic acid), were hydrothermally synthesized from a rigid aromatic carboxylate ligand and a pyridine ligand containing free amino groups. 1 exhibits a novel (4,4,5,5)-c 2D layer architecture with 1D pipe-like chains. 2 shows a 3D framework with an unprecedented (4,4,4,6,7)-c topology. Their structural differences mainly stem from the various coordination modes of the rigid aromatic carboxylate ligand. Luminescence sensing experiments exhibit that 1 can highly sensitively and selectively detect TNP in DMF and H2O. Moreover, test paper was developed to detect TNP as a convenient and practicable approach. In addition, 1 shows highly sensitive and selective sensing of Cu2+. The possible detection mechanisms of 1 towards TNP and Cu2+ have been discussed. These experimental results suggest that 1 should be a potential sensor for TNP and Cu2+. [ABSTRACT FROM AUTHOR]

Synthesis of two homoleptic and five heteroleptic zinc (II) carboxylate complexes with two different ligands: HL1 = 3-chlorobenzoic acid and HL2 = 2-(4-chlorophenyl) acetic acid have been reported in this paper. The general formulae of the two homoleptic complexes are: Zn(L1)2(1), and Zn(L2)2(2). Similarly, the general formulae for two different types of heteroleptic complexes are: (Type-I): [(Zn)2(L1)4(bipy)2(H2O)] (3), [Zn(L2)2(bipy)(H2O)] (4) and (Type-II): [ZnL1L2] (5), [ZnL1L2(py)] (6) and [ZnL1L2(bipy)] (7). The synthesized complexes were characterized in the solid state by FT-IR, CHN analyses and in solution state by NMR (1H, 13C) spectroscopy. Complexes 3 and 4 were also characterized by single crystal analysis where data revealed that the geometry around each Zn atom is distorted trigonal bipyramidal and octahedral, respectively. The synthesized complexes were interacted with SS-DNA and CTAB (surfactant). Interaction of the synthesized compounds with SS-DNA was studied by UV–visible spectroscopy and viscometry and intercalative mode of interaction was exhibited. Moreover, the interaction of the synthesized complexes with CTAB was studied by conductometry showing a strong binding that is evident from higher CMC and negative Gibbs free energy of micellization (ΔGm) values. The tested compounds were further screened for in vitro antibacterial and antifungal activities and were found active against the studied strains of bacteria and fungus. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the formation and decomposition of silica embedded metal carboxylates obtained using Co-, Fe- and Ni- nitrates and polyols with different structure and molecular weight (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2,3-propanetriol). The thermal behavior of carboxylate precursors (oxalic, malonic, lactic, hydroxymalonic and succinic) is similar for all used polyols, both the formation and decomposition of precursors occurring in two stages. However, the mass loss slightly increases with increasing of the diol chain length and significantly increases with the presence of a supplementary, nonreactive secondary hydroxyl group. X-ray diffraction shows the formation of NiO single phase or NiO and CoFe 2 O 4 mixtures below 750 °C, and of mixed Co-Ni ferrite single phase at 1000 °C, while Fourier transformed infrared spectroscopy confirms the formation of silica matrix and the formation and decomposition of carboxylate precursors. Transmission electron microscopy shows spherical nanoparticles of different size. The Ni 0.5 Co 0.5 Fe 2 O 4 nanocrystallites size (4.3–28.1 nm) and relative crystallinity (4–100 a.u.) increase with the annealing temperature, the diol chain length and the distance between hydroxyl groups. The coercive field (0.015–0.6 T) and saturation magnetization (21.5–25 emu/g) of gels annealed at 1000 °C also increase for longer chain length diols. [ABSTRACT FROM AUTHOR]

Highlights • Solutions of chitosan carboxylates without backbone depolymerisation. • Method to obtain transparent and sorption-active polysalt films. • Determination of the dynamic vapour sorption rate-constants of polysalt films. • Correlation of the steric demand and acid strength with sorption kinetics. • Thermal stability of chitosan carboxylates higher than hydrochloride. Abstract In this paper we describe the preparation of alkanoic acid-based aqueous chitosan solutions, which show no sign of acid-catalysed depolymerisation over time – something commonly accompanying other preparation methods. Longer chitosan chains have previously been shown to exhibit more advantageous biological activities, and constant viscosities are essential for consistent quality in biomedical applications. Avoiding acid-catalysed depolymerisation requires careful control of the stoichiometry between the free amino groups of chitosan and the appropriate solubilising acid. Acetic and butyric acid are both suitable solubilising agents, but chitosan butyrate exhibits lower solution viscosities due to a combined electric and steric shielding of the chains. These solutions dry into clear transparent films that remain fully water soluble and absorb up to 70 wt% of water from 90%-RH vapour phase at 25 °C. The absorption follows simple first-order kinetics and the rate constants increase with increasing humidity up to approx. 71%-RH, where a metastable chitosan trihydrate salt appears to be formed. Desorption is slightly faster, but more complex, as it exhibits two distinct first-order processes. In addition, films prepared in this way are thermally more stable than the usual chitosan hydrochloride. [ABSTRACT FROM AUTHOR]

Polyoxometalates (POMs) are commonly prepared using a “bottom-up” synthetic procedure. The alternative “top-down” approach of disassembling a pre-formed POM unit to generate new synthetic intermediates is promising, but relatively comparatively underused. In this paper, a rationale for the top-down method is provided, demonstrating that this approach can generate compounds that are fundamentally inaccessible from simple bottom-up assembly. We demonstrate this principle through the synthesis of a series of 10, new, mixed-metal, hybrid compounds with the general formula [TBA]2[MoVI10CoII6O30(RpPO3)6(RcCOO)2(L)x(H2O)6] (TBA = tetrabutylammonium, Rp = phosphonate moiety, Rc = carboxylate moiety, L = pyridyl ligand, and x = 2–4), including a one-dimensional polyoxometalate-based coordination polymer. We propose that these structures are generated from {MoxO3x−1} fragments that cannot be accessed from bottom-up assembly alone. The POM clusters are stabilised by three distinct classes of organic ligand – organophosphonate, carboxylate and pyridyl ligands – which can each be substituted independantly, thus providing a controlled route to ligand functionalisation. [ABSTRACT FROM AUTHOR]

In this paper, we describe the use of p‐TSA based Deep Eutectic Solvents (DESs) as alternative environmental‐friendly "active" solvents for the microwave‐mediated synthesis of 6‐substituted 3,4‐fused 2‐pyranones, and in particular isocoumarins, starting from 2‐alkynyl‐(hetero)arylcarboxylates. When the alkyne terminus bears a neutral or an electron‐donating group (EDG), the reactions are fast, clean and highly regioselective, to give the 6‐endo‐dig cyclization products in good to excellent yields. For substrates bearing an electron‐withdrawing group (EWG) on the alkyne end, the regioselectivity can be tuned by adding a small amount of silver(I) triflate as co‐catalyst. DES was demonstrated to be reusable without loss of efficiency in terms of reaction yields. Based on experimental evidence and previous findings, two competitive mechanisms working simultaneously are proposed to explain the outcomes and the regioselectivity issues. An acidic Deep Eutectic Solvent is an alternative environmental‐friendly "active" media for the microwave‐mediated synthesis of 6‐substituted 3,4‐fused 2‐pyranones. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • We fabricated a salt-bond crosslinked supramolecular hybrid network. • Nano-chitosan served as crosslinking points in constructing the network. • Enhanced mechanical properties without sacrifice of self-healing property. • Tensile strength of composite is more than 2-time that of neat rubber matrix. • Healing efficiency achieved 92% after healing for 24 h. Abstract In this paper, carboxylated styrene butadiene rubber (XSBR)/nano-chitosan (NCS) composites were prepared via a salt-forming reaction, in which NCS participated in constructing a supramolecular hybrid network. NCS served as multiple-functional cross-linker as well as reinforcer for XSBR. This turned out that the mechanical properties of XSBR could be improved by NCS, and simultaneously, the self-healing property was retained to utmost extent. With 20 wt% NCS, the tensile strength of NCS/XSBR composite was increased to 1.3 MPa, more than 2-time that of the neat XSBR, meanwhile, the healing efficiency was as high as to 92% after healing at ambient temperature for 24 h. [ABSTRACT FROM AUTHOR]

Highlights • Mixing sequences of Ca2+ and PCE play an important role in dispersing low grade SF. • Priority adsorption of Ca2+ to low grade SF favors adsorption of PCE on SF. • The higher fluidity of CS2 paste benefits from Ca2+ ion pre-treated silica fume. • The compressive strength of CS2 is improved. Abstract Effective use of low grade silica fume (SF) is of both environmental and economic significance. However its low pozzolanic reactivity, presence of large fused aggregates and poor adsorption of dispersant such as polycarboxylate superplasticizer (PCE) hinder its application in cement and concrete. Recent studies have focused on effect of cationic ions on PCE adsorption on silica fume, but attempts have not been made on low grade SF. In this paper, effect of different mixing sequences of cationic calcium ions (Ca2+) and anionic polycarboxylate superplasticizer (PCE) on dispersing a low grade SF was compared in both aqueous suspension and cement paste. In the aqueous suspension, adsorption and dispersion behavior of low grade SF suspension mixed with different sequence of calcium ion and PCE were characterized by Total Organic Carbon (TOC) test, free settling test and laser particle size test. Results showed that priority adsorption of Ca2+ followed by PCE to low grade SF suspension (sample SF2) favored adsorption of PCE on SF. After sequential addition of Ca2+ and PCE to the SF, sample SF2 had the best anti-free settling ability and particle dispersion. In the cement paste, the sample that had priority mixing of Ca2+ ions with low grade SF followed by addition of PCE, water and cement (CS2, corresponding to SF2) was verified to have better fluidity than the control sample (CS0, corresponding to SF0) that was prepared by mixing PCE, water, SF and cement (including abundant Ca2+ ions). The hardened cement paste with pretreated SF had higher strength and more effective silica fume dispersion in the cement matrix. [ABSTRACT FROM AUTHOR]

Graphical abstract This review presents the research progresses on CCMPs made in the past decades, including various synthesis methodologies, structural features and relevant applications with regard to their photochromism, photoluminescence and magnetic properties. Highlights • Organic inorganic hybrid POMs with remarkable physical and chemical properties. • Organic carboxylic acid ligands can directly covalently graft to the POM skeletons. • A new kind of structurally diverse organic inorganic POM-based materials. • Displaying potential applications in optics, electrochromism and photochromism. Abstract Polyoxometalates (POMs) have demonstrated strong potential in various fields, such as catalysis, magnetism, medicine, photochemistry and materials science, for their remarkable physical and chemical properties. Through the introduction of organic functional moieties to the POM systems via self-assembly, grafting, doping or intercalation strategies, advantages from both the POMs and organic moieties are well maintained, resulting in many new properties. Among all the existing organo-functionalized POMs, carboxylate covalently modified POMs (CCMPs, carboxylic acid ligands covalently grafted to the POM skeletons) attract intensive research efforts. The carboxylic acid ligands not only help to enrich the structural diversities of the CCMPs, but also facilitate the tuning of redox behaviors and photoreduction activities of the CCMPs because of the possible electron transfer between the organic ligands and the POM units. Encouraged by the impressive structural diversities and potential applications in optics, magnetism and materials science, the design and exploration of new CCMP complexes have become some of the most compelling and challenging areas in POM chemistry. In this review, we herein discuss the research progress achieved for CCMPs in the past decades in the areas of synthesis methodologies, structural features and relevant applications (photochromism, photoluminescence and magnetism, etc.). In addition, some personal insights are also presented in the last section of the paper with sincere wishes for continuous exploration of the undiscovered world of CCMPs. [ABSTRACT FROM AUTHOR]

Abstract Understanding structure function relationships of chemical admixtures is a long-standing objective of researchers in this field. In this paper, we determine how to optimize the PCE structure to change retardation without compromising workability of cementitious materials. For this, we establish a relationship between molecular structure of PCEs and yield stress of suspensions. We combine the obtained relationships with a previously published correlation between the molecular structure of PCEs and the retardation that they cause to produce an optimization plot allowing to select the molecular structure giving any desired combination of fluidity and retardation in cement pastes. This plot represents the first tool for mechanistically based molecular optimization. The advantages of using such an optimization chart, its industrial implications, as well as the potential limitations coming from its experimental development are discussed. [ABSTRACT FROM AUTHOR]

Abstract In this paper structure, thermodynamic, and dynamic properties were investigated for series of selected protic ionic liquids, methylmorpholinium ([MeMorph]+) and ethylmorpholinium ([EtMorph]+) with carboxylate formate ([For]−) and acetate ([Ace]−) anions, using quantum chemical calculations and molecular dynamics simulations. Relative geometrical structure, H atom transfer between anion-cation, charge transfer and the polarizability was calculated and studied. As a result, anion type (characterized by the alkyl chain length) has the major influence on the charge and H atom transfer with subsequent influences on physiochemical properties. Irregularity in the trend of thermodynamic properties of these ILs (observed experimentally) was described by the extent of charge transfer of atom we estimated by scanning the anion-cation distance. Molecular dynamics simulations indicated a substantially lower density for [MeMorph][Ace] than [MeMorph][For], consistent with reported experiment, and demonstrate the high impact of anion type on thermodynamic properties. Radial distribution function g (r), demonstrates cations and anions tightly bond in the first coordinate shell but bond loosely in second and third shells as the anion alkyl chain increases. Adhering to this, special distribution functions demonstrate the more compactness and higher anion distributing around cation for [MeMorph][For] than the other two ILs. As regards the accuracy of simulation of transport property (the viscosity) of ILs, the scaling down of partial-charges was found necessary to account for electrostatic interaction with the nonpolarizable force field used. Required scaling depends on the diversity of anion-cation charge transfer. These simulations, consistent highly with experiment, exclusively provide insight into the details of less impact ILs that would be obtained by larger size alkyl substituent on carboxylate anion. Graphical abstract Unlabelled Image Highlights • Protic morpholinium (with formate and acetate) ionic liquids are simulated by MD. • Charges and detailed anion-cation charge and H transfer is studied by MP2 and DFT. • Anion-cation binding is remained tight up to third shell for the short chain anion. • The reported relative low compactness of IL with long chain anion is elucidated. • Viscosity is simulated agreeably by non-polarizable FF and charges scaled down. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The biopolymer-based from cassava starch (CS) and cellulose fiber (CF) from sugar cane leave was made by help of carboxylated styrene-butadiene rubber (CSBR) as an adhesion. • The addition of the cellulose fiber in the CSBR/CS blend exhibited higher in tensile strength compared to unfilled CF sample. • This study demonstrated a significant concentration of the CF improved the film properties. • The inexpensive biodegradable film was expected to be a promising candidate for alternative packaging materials. Abstract The biopolymer-based from cassava starch (CS) and cellulose fiber (CF) from sugar cane leaves was prepared by help of carboxylated styrene-butadiene rubber (CSBR) as an adhesion. The CF was isolated by using acid hydrolysis under heating (50 wt%, 140 °C for 2 h). The size, morphology, chemical structure, interaction bonding, dynamic mechanical behavior, thermal analysis, biodegradation, physical and mechanical performance of CSBR/CS/CF composites were investigated. The highest tensile value was found at 1.6 wt% CF loading (27.96 MPa) while preserving the large extent of their biodegradability (<80% after buried in soil for 30 days). Moreover, the increasing CF content led to decrease in the water contact angle, moisture content owing to the interfacial adhesion between carboxyl groups on the CSBR and hydroxyl groups on the CF surfaces. This study demonstrated a significant concentration of the CF on film properties. Moreover, these inexpensive biodegradable composites were preferable for packing, fruit container and paper coating applications. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to investigate and prepare the composite polyurea greases with excellent thermal stability and tribological properties.Design/methodology/approach In this paper, composite Ba-based (Ba, barium) tetra-polyurea lubricating greases were prepared with two different methods: mixing Ba-based gelatinizer and tetra-polyurea gelatinizer by a physical method; and introducing barium carboxylate into tetra-polyurea molecules by a chemical method. The properties of the products, such as heat stability, water resistance and friction performance, were analyzed with thermogravimetry, water-resistance test and four-ball friction test.Findings The results indicated that the products obtained by chemically introducing barium carboxylate into tetra-urea molecules showed better elevated temperature tribological properties, and the disadvantages of the polyurea greases with high temperature hardening were also obviously improved. The cone penetration rate at 180°C for 24 h is only 3 per cent. The friction coefficient can be decreased to 0.44 and the last non-seizure load value was increased from 560 N to 1,120 N without any other additives.Originality/value The research is significant because the prepared composite grease showed excellent performances, such as the outstanding thermal stability, water resistance and excellent extreme pressure and anti-wear properties, which may be widely applied in steel, metallurgy, bearings and other industrial fields. [ABSTRACT FROM AUTHOR]

Highlights • The workability of cemented tailings backfill (CTB) are greatly affected by solid content, superplasticizer type and dosage. • The best performance on fluidity behavior of fresh CTB mixtures are obtained from the naphthalene-based admixtures. • The mechanical strength performance of CPB samples can be increased significantly by the superplasticizer added to the backfill mix. Abstract This paper presents the coupled effect of solid content and superplasticizer type and dosage on the fluidity and strength properties of cemented tailings backfills (CTB). A total of three different superplasticizers (namely, naphthalene, ether-based and ester-based polycarboxylate) were used at a ratio varying from 0% to 0.5% by mass of CTB. The CTB mixes were proportioned with a solid content of 65%, 66%, 68% and 70%. The unconfined compressive strength tests were performed on CTB samples after 3, 7 and 28 days of curing period. The obtained results show that the effect of superplasticizer on CTB performance depends on type and dosage of the superplasticizer used as well as solid content. The naphthalene-based polycarboxylate admixtures demonstrate the best improvement on fluidity behavior of fresh CTB mixture. For a given superplasticizer type, increases in the dosage of superplasticizer and decreases in the solid content lead to better workability of CTB samples. When increasing solid content, fresh CTB with high superplasticizer dosage performs a relatively low rate of decrease in the workability. A relatively high solid content and superplasticizer dosage have greatly contributed to improved mechanical strengths, especially at 28-day curing age, mainly due to a major reduction in water-to-cement ratio and porosity. [ABSTRACT FROM AUTHOR]

Production of bio-based acetate is commonly hindered by the high costs of the downstream processing. In this paper, a model is developed to describe a new method that recovers acetate salts using anion exchange resins, and subsequently desorbs and upgrades them using CO 2 -expanded alcohol. The model consists of equilibrium parameters for both the adsorption and desorption step. The calculated parameters are: for the adsorption K C l - Ac - = 0.125 , K C l - HC O 3 - = 0.206 and K OV , HAc = 0.674 mol / kg resin mol / kg solution , and for the desorption p K MeCO 3 - Ac - = 3.71 . The maximum experimental concentration of acetic acid obtained in CO 2 -expanded methanol is 0.427 mol/kg (20 g/L MeOH ) at an operating pressure of 31 bar. The model represents the expected trends for all species, and can be used to design a multicolumn system for the recovery and upgrading of carboxylates. [ABSTRACT FROM AUTHOR]

A fundamental issue in beryllium research is the search for suitable chelating ligands for environmental and biomedical application. In this paper, the speciation of beryllium ions with several multidentate aminopolycarboxylic acids, which are well-known commercial and biomedical chelating agents, has been investigated using electrospray ionisation mass spectrometry (ESI MS). Stoichiometric information, which was readily obtained from the ESI mass spectra, was found to be effective for the preliminary screening of potential encapsulation by tetradentate coordination from a single ligand. Ions observed by ESI MS revealed that the pre-existing solution species and binding affinity trends were preserved into the gas phase in good agreement with previous solution speciation data, suggesting the ability of ESI MS to be developed as a quick, sensitive and safe screening technique to observe beryllium speciation with ligands of interest at low concentrations. The disruption of beryllium-ligand binding by addition of other di- or trivalent metal cations is also reported. [ABSTRACT FROM AUTHOR]