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In this work, a thermodynamic study of the Zn(II)/L systems (L− = acetate, AcO− or indomethacin anion, Indo− or diclofenac anion, Dic−) in ethanolic solution was carried out by isothermal titration calorimetry (ITC). Thermodynamic properties such as enthalpy (∆H), entropy (ΔS), Gibbs energy (ΔG) and formation constant (reported as logβi) associated with the complexation reactions were determined; the stoichiometry of the formed species was also found. Zn(II)/AcO− was used as a model system for the complexation of Zn(II) with indomethacin and diclofenac anions, because all of them coordinate through the carboxylate functional group. To determine the thermodynamic properties of each system under study, from the experimental results, a binding model has been devised to calculate the heat Qcalc that is released or absorbed in terms of the molar ratio r L/Zn II in the complexation process between Zn(II) and L−. Calculated data (Qcalc) are adjusted to the ITC experimental results (Qexp), by means of MicroCal PEAQ-ITC analysis software to determine the enthalpy and formation constants of the MLj(2−j) formed complexes. Distribution diagrams of the fractions of the M and L species were obtained as a function of the molar ratio to discuss the predominance of the species in the systems as the titration was carried out. [ABSTRACT FROM AUTHOR]

A better understanding of adsorption mechanism is vital for the effective reduction of tungsten mobility and potential human health risk such as its suspected link to the childhood leukemia clusters. This study investigated tungstate (WO42-) adsorption characteristic onto montmorillonite under environmentally relevant solution properties such as the influence of reaction time, solution pH, initial concentration, the competitive anion (PO43-), and ionic strength. The results of the adsorption isotherm studies suggested that both the Langmuir (R²= 0.9117) and Freundlich (R²= 0.9913) equations can be well consistent with WO42- adsorption process and the maximal WO42- adsorption capacity was 26.73 mmol kg-1. The amount of WO42- adsorbed onto montmorillonite strongly dependent on pH and slightly dependent on ionic strength. Specifically, WO42- adsorption reached the maximum (17.41 mmol kg-1) at pH 4.15, but becoming negligible (<10%) when pH increase above 9. PO43- competed for adsorption sites on montmorillonite with WO42-. The results of this study indicated that the adsorption mechanism of WO42- onto montmorillonite involved ion exchange, inner-sphere surface complexation reaction, and electrostatic attraction. Collectively, our study will aid the understanding of tungsten fate and these results suggest that montmorillonite can be advantageous to the adsorption and recovery of tungsten from real wastewater. [ABSTRACT FROM AUTHOR]

Abstract This study aims at the further expansion of knowledge on the antimicrobial activities of the tetramic acid moiety and the effect of metal complexation. Complexes of the N -acetyl-3-acetyl-5-benzylidenetetramic acid with Mn, Co, Ni, Cu, Zn and Cd were synthesized and screened against 5 key ESKAPE pathogens (Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa) and 2 fungi (Cryptococcus neoformans and Candida albicans). The cadmium complex was found to effectively inhibit the fungus Cryptococcus neoformans with minimum inhibitory concentration (MIC) of 8 μg/mL, with no human cell toxicity and hemolytic activity within the tested concentration range. The biologically active tetramic acid‑cadmium complex was structurally characterized by single-crystal X-ray analysis. Furthermore, the thermal stability of the ligand and the complexes was investigated along with NMR and EPR studies of the Cd(II) and Co(II) complexes respectively. Graphical abstract A series of metal(II)-tetramic acid complexes was synthesized and investigated for antimicrobial activities. The novel compounds were structurally characterized by single-crystal X-ray, NMR, EPR, UV and thermogravimetric (TG) analyses. The Cd(II) complex displayed effective inhibition activity against Cryptococcus neoformans , being at the same time non-cytotoxic and non-hemolytic. Unlabelled Image Highlights • Synthesis of four novel metal(II) complexes of a 5-benzylidene tetramic acid • EPR studies of the Co(II) complex • Cd(II) complex displayed high antifungal activity against Cryptococcus neoformans. • The active Cd(II) complex was found to be non-toxic and non-hemolytic. • Single-crystal X-ray analysis of the bioactive Cd(II) complex [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Incorporating nanochitin into hydrogels greatly improves Cu(II) adsorption ability. • Magnetic microparticles endow hydrogels with remote separation capacity. • Hydrogel's ions adsorption comes from nano/micro-effect and complexation interactions. • Adsorption occurs via the models of pseudo-second-order kinetic and Langmuir isotherm. Abstract In this study, Fe 3 O 4 -nanoparticles-contained polyamide 6 (PA 6) microparticles (FP) were developed by a first dispersion of Fe 3 O 4 -nanoparticles in ε-caprolactam (CL) monomer in the presence of polystyrene (PS) and a subsequent in situ CL open polymerization into PA 6, followed by PS removal. The FP microparticles (as magnetic separation material) and nanochitin (n-CT, as an effective metal-cation natural adsorbent) were then in situ encapsulated into poly(vinyl alcohol)-enhanced chitosan hybrids (PVA/CTS) to form biodegradable nanocomposite hydrogels (FPCC) with magnetic separation ability. The FPCC hybridized hydrogels enabled about 1.7-fold Cu(II) adsorption capacity as compared to the pure PVA/CTS hydrogels with a Cu(II) adsorption value of 38.7 mg/g. More attractively, the adsorption equilibrium could be achieved within 10 min, which is quicker than many previous adsorbents. Furthermore, simulation results indicated that Cu(II) adsorption behaviors of the hybrid hydrogels conform to a pseudo-second-order kinetic model and a Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

Abstract Owing to its excellent mechanical properties, processability, and biodegradability, poly(lactic acid) (PLA) has been widely investigated in the past few decades as a biomaterial. However, the poor heat resistance of PLA severely limits its applicability. In this review, several heat resistance modification methods, such as nucleating agent addition, fiber reinforcement, compounding, blending, stereoisomer complexation, and chemical modification, have been reviewed and their related mechanisms have been discussed in brief. [ABSTRACT FROM AUTHOR]

Density functional theory calculations, using the B3LYP parameterisation, were performed to determine structures, vibrational frequencies, and binding energies for complexation of Ni+ and Ni2+ cations with benzene and naphthalene molecules and clusters. The calculations employed the Stuttgart basis set with ECP pseudo potentials for the Ni cations and basis sets of at least triple ζ plus polarisation, and diffuse quality for C and H. The effect of electron correlation on non-bonded interactions was accounted for by the Grimme GD3 dispersion correction. Counterpoise computations were made for BSSE. Comparison between experiment and theory provide fascinating new insight into the bonding for these prototypical organometallic (OM) complexes. These structures have a sandwich topology, indicating major structural reorganisations occuring when benzene or naphthalene interact with Ni cations. Adiabatic electron affinities and ionisation potentials agree well with experiment when available. Binding energies were also determined, providing insight into the stability of the complexes. The results presented here provide important information for future studies to address additional investigations of both problems of the electronic structure properties of these complexes, as well as the role of the polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM) and soot formation in combustion. The Ni+/Ni2+ + aromatic organometallic bonding is of the same order of stability as an aromatic C–H bond. Such bonding modifies the IR spectrum of the complexed aromatic molecules by enhancing the 3.3 μm feature and decreasing the C–H bands in the 11–12 μm range (γ C–H). Organometallic complexation reactions may contribute significantly to metal depletion in the ISM. [ABSTRACT FROM AUTHOR]

In this study, we measured the effect of EPS on Cd and proton adsorption behaviors by measuring the extent of adsorption onto biomass with and without the EPS removed via a cation exchange resin. We conducted both Cd adsorption experiments and potentiometric titrations of biomass using three common bacterial species: one Gram-positive (Bacillus subtilis) and two Gram-negative (Shewanella oneidensis, Pseudomonas putida) species. The Cd adsorption experiments were conducted as a function of metal loading in order to probe whether environmentally-low metal loadings lead to different adsorption mechanisms and roles for EPS than the higher metal loadings of most previous adsorption studies. We suspended each biomass sample in a solution of dissolved Cd in 0.01 M NaClO4 at metal loadings of 1, 2, 5, and 74 μmol/g. Surface complexation modeling (SCM) was used to determine stability constants for the important Cd-bacteria complexes, and the effect of metal loading on the resulting calculated stability constant values was determined. In general, the measured bulk Cd adsorption behavior is unaffected by EPS removal. However, our potentiometric titration results suggest that EPS removal does alter the distribution of site types, but not the mass-normalized total site concentration within the biomass. SCM suggests that high affinity sulfhydryl sites control Cd binding under low metal loading conditions for B. subtilis and P. putida, and that sulfhydryl sites are present both on the cells and within the EPS for these species. Conversely, the SCM results suggest that Cd-sulfhydryl binding is un-important on the EPS of S. oneidensis. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The isothermal titration calorimetry was applied to the complexation of humic acid, which was isolated from deep groundwater. • The complexation thermodynamic quantities of humic acid with copper (II) ions and uranyl (VI) ions were determined. • The unique complexation character of deep groundwater humic acid was revealed by reaction thermodynamics. • Determination of complexation enthalpy of in situ humic substances is helpful for the prediction of radionuclides migration. Abstract Although the thermodynamic quantities (Gibbs free energy, reaction enthalpy, and entropy) of the complexation of humic acid are necessary for the discussion of the reaction thermodynamics, their accurate determination, especially concerning dissolved humic acid in deep groundwater, has not been carried out. In this study, a combination of potentiometry and calorimetry was used for the determination of the thermodynamic values of complexation of typical humic acid and groundwater humic acid, which was isolated from deep groundwater at Horonobe, Hokkaido, Japan, with copper (II) ions and uranyl (VI) ions. The apparent complexation constant of Horonobe humic acid was independent of the pH of the bulk solution, whereas that of typical humic acid was dependent on the pH. This observation indicates that the polyelectrolyte effect of Horonobe humic acid is negligible because of its relatively small molecular size. In addition, the effect of the heterogeneity of Horonobe humic acid was not significant. Moreover, the complexation enthalpy of Horonobe humic acid was consistent with that of homogeneous poly(acrylic acid), which means the complexation of Horonobe humic acid was not affected by the functional group heterogeneity. Consequently, the unique complexation mechanism of Horonobe humic acid was revealed based on the determined thermodynamic quantities. The migration of radionuclides in the deep underground environment must be affected by these characteristics; thus, the accurate determination of thermodynamic quantities of in situ humic substances is very helpful for the safety assessment of geological disposal, when disposal sites for radioactive waste are chosen. [ABSTRACT FROM AUTHOR]

Applications of aluminium (Al) salt or lanthanum (La) modified bentonite (LMB) have become popular methodologies for immobilizing phosphorus (P) in eutrophic lakes. The presence of humic substances, has been shown to inhibit this form of treatment due to the complexation with La/Al. However, the effects of other dissolved organic matter (DOM), especially that derived from phytoplankton (the dominant source in eutrophic lakes) are unknown. In this study, the interaction with La/Al of Suwannee River Standard Humic Acid Standard II (SRHA) and algae-derived DOM (ADOM) were investigated and compared. Differed to SRHA which was dominated by polyphenol-like component (76.8%, C1-SRHA), majority in ADOM were protein-like substance, including 41.9% tryptophan-like component (C2-ADOM) and 21.0% tyrosine-like component (C3-ADOM). Two reactions of complexation and coprecipitation were observed between SRHA/ADOM and La/Al. Complexation dominated at low metal inputs less than 10 μM and coprecipitation was the main reaction at higher metal inputs. For ADOM, the tryptophan-like component (C2-ADOM) was the important component to react with metal. The reaction rate for C2-ADOM with La were about two-third of that for C1-SRHA, indicating that the influence of C2-ADOM was significant during the P immobilization by La/Al-based treatment in eutrophic lakes. The P removal data in the presence of ADOM confirmed the significant inhibition of ADOM. In addition, based on the composition of coprecipitates and relatively biodegradable character of tryptophan-like substances (C2-ADOM), the coprecipitation of ADOM was assumed to reduce the stability of precipitated P in eutrophic lakes. The release of P from the potential biodegradation of the coprecipitates and thus the possible decline of the performance of P immobilization by La/Al-based treatments is an important work in the future. Image 1 • Complexation and coprecipitation occurred between SRHA/ADOM and La/Al. • A tryptophan-like component of ADOM complexed strongly with La. • The tryptophan-like component has strong ability to coprecipitate with La and Al. • The behaviors of PARAFAC components explained the inhibitory effect of SRHA/ADOM on P removal. • The stability of coprecipitates of DOM, Al/La and P should be noted. [ABSTRACT FROM AUTHOR]

BACKGROUND Renewable resources have been considered for producing many advanced materials. In this respect, silver‐doped carbon‐based materials with a low loading capacity and high antibacterial activity can also be generated via environmentally friendly routes and from renewable resources. RESULTS: Silver‐doped carbon fibers were prepared from wood and cotton fibers via complexation and reduction reactions for depositing silver on the fibers and subsequently via carbonization of the loaded fibers. Silver loading before carbonization enhanced the stability of silver on the carbonized fibers, decreased silver loss (from 30 to 12%) and lowered the silver loading (5.66%) needed to achieve excellent antibacterial activity. However, wood‐based silver‐doped carbon fibers performed better than cotton‐based carbon fibers with respect to loss of antibacterial activity (12% at a silver loading of 5.66% versus 24% at a silver loading of 7.97% in 800 h respectively). These results are attributed to more uniformity in the distribution of silver nanoparticles in the porous structure of wood fibers than in cotton fibers. CONCLUSION: The wood‐based carbon fibers exhibited better antibacterial activity and stronger affinity for maintaining silver and lower required silver loadings, and the sequence of silver loading and carbonization was crucial in developing silver‐loaded carbon fibers with good antibacterial performance. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract Functional groups in natural organic matter have the potential to interact with and stabilize iron (Fe) redox species (ferric, ferrous) through complexation reactions. In this study, iron complexes with cysteine, arginine and histidine are used to investigate the extent to which specific functional groups present in these amino acids might hinder the oxidation of Fe2+ or promote the reduction of Fe3+. Iron complexes are synthesized by addition of ferrous or ferric salts to cysteine, arginine and histidine solutions at pH 7. The Fe-amino acid complexes are analysed using X-ray Absorption Spectroscopy (XAS), theoretical CTM4XAS (Charge Transfer Multiplet for XAS) calculations, and vibrational spectroscopy (FTIR and Raman). In addition, oxidation of the amino acids is determined by linear sweep voltammetry and chemical equilibrium modeling is used to predict the speciation of Fe in complexes with the amino acids. It is observed the extent of Fe redox transformation is affected by the electron donating capability of the ligand with which Fe reacts. In particular, the extent of Fe3+ reduction is related to the oxidation of the ligand with 80, 14 and 0% Fe3+ reduction by cysteine, arginine and histidine, respectively. Conversely, Fe2+ is preserved by cysteine (80%) > arginine (77%) > histidine (62%). The chemical forms of Fe in these mixed Fe oxidation-state systems include Fe-organic complexes and Fe precipitates. XAS and vibrational spectroscopy indicate thiol-S and amino-N bind Fe in complexes with cysteine. While amino-N and guanidyl-N functional groups of arginine bind Fe, carboxylate-O binding and the formation of Fe precipitates are only observed when Fe3+ is the predominant redox species. Whereas Fe precipitates seem to prevail in Fe(III)-histidine, distinct organic (Fe O/N C) and mineral (Fe O Fe) or mixed organic-mineral (Fe(O/N C) x (O Fe) y) coordination environments occur in Fe(II)-histidine with ∼60% Fe2+; in either case, Fe N(imidazole) binding is not evident. The ligand atoms to which Fe binds and the inherent reduction capacity of the ligand appear to mediate Fe redox transformations. The proportion of ferric iron (Fe3+) seems to determine whether a precipitate forms. Consistent with spectroscopic data, chemical equilibrium modeling using experimental solution conditions and fractional Fe2+ and Fe3+ concentrations obtained from CTM4XAS predict the formation of Fe(II)- and Fe(III)-amino acid complexes and hydrolyzed Fe species; these calculations however also predict the formation of Fe oxide precipitates in all Fe complexes. The results presented in this study help to explain the co-occurrence of Fe2+ and Fe3+ in natural environments where organic matter is present. They also highlight the role specific organic functional groups play on the formation and stabilization of Fe(II, III)-organic complexes and precipitates, and thus on the Fe redox cycle which affects Fe bioavailability and mobility in terrestrial and subsurface environments. [ABSTRACT FROM AUTHOR]

A facile method for preparing various functional cycloalkynes, including proteins incorporated with a cycloalkyne moiety, from the corresponding azides is developed. Treatment of diynes bearing strained and terminal alkyne moieties with a copper salt enabled terminal alkyne-selective click conjugation with azides, whereas a more azidophilic strained alkyne moiety was transiently protected from the click reaction via complexation with copper. [ABSTRACT FROM AUTHOR]

An efficient and practical strategy has been established to enhance the configurational stability of chiral tricyclic dipeptide, which readily undergoes spontaneous racemization under environmental conditions. Complexation of the chiral dipeptide with racemic diols via non‐covalent interaction results in the corresponding heterocomplexes (HCs), which are able to preserve chirality of the dipeptide as long as 24 months. A nearly quantitative recovery of enantiopure dipeptide and racemic diols was achieved by simple treatment of the HCs with a biphasic system of H2O‐ethyl acetate and subsequent separation from aqueous and organic layers, respectively. This study not only provides a facile and handy method for the configurational stabilization of the chiral dipeptide, but also opens a further prospect for the long‐term chirality preservation of other instable enantiomeric compounds via heterocomplexation approach. An efficient and practical strategy has been established to enhance the configurational stability of chiral tricyclic dipeptide via heterocomplexation with chiral diols. A nearly quantitative recovery of enantiopure (S,S)‐1 and racemic diols was achieved by simple treatment of the heterocomplex with a biphasic system of H2O‐ethyl acetate and subsequent separation from aqueous and organic layers, respectively. [ABSTRACT FROM AUTHOR]

Abstract In our previous work, we highlighted the thermodynamic and spectroscopic characteristics of the 1:1 charge transfer (CT) complexation of TCNE acceptor with various medically important drugs. Continuing that work, we further examine drugs that react with the TCNE acceptor via a 1:2 interaction. The examined drugs are atenolol, quinidine, cimetidine, reserpine, and levofloxacin. We aimed through this study to: i) make the spectrophotometric and thermodynamic data of the examined drugs, both initially and when reacted via a 1:2 M ratio with the TCNE acceptor, available to use in the determination or detection of these drugs in pharmaceuticals and other environments; and ii) compare the mode of interactions and the spectrophotometric and thermodynamic properties between drugs that react via a 1:1 or 1:2 ratio with the TCNE acceptor. To achieve these aims, the five examined drugs were reacted with TCNE in acetonitrile (MeCN) solvent at room temperature. Several thermodynamic and spectroscopic data were experimentally estimated using the van't Hoff and the Benesi–Hildebrand equations and discussed. Graphical Abstract Electronic absorption spectrum of the CT product that formed form the reaction of drug Qui with TCNE acceptor in MeCN solvent. Unlabelled Image Highlights • CT complexes were obtained by the reaction of different drugs with TCNE. • Electronic spectra show a very strong absorption band at 405 nm with two heads. • Experimental data suggest that the complexation occurs via n→π* and π→π* interactions. • The van't Hoff plot was employed to determine the thermodynamic data. • The Benesi–Hildebrand plot was employed to determine the spectroscopic data. [ABSTRACT FROM AUTHOR]

Abstract Kinetic study on the complexation of caffeic acid with ferric chloride was performed in aqueous solution at pH 9.0. The complex was characterized by IR, UV–Vis spectroscopy and FE-SEM techniques. Kinetic data were obtained and used to model the reaction kinetics for the disappearance of the caffeic acid. The operational variables have been studied in the temperature range from 25 to 45 °C, initial iron and caffeic acid concentration from 0.6 mg/100 ml (ranging from 2.0 ml to 8 ml/100 ml). The complexation reaction was found to be a first-order with rate constants for k 1 (formation) 4.7 × 10−3 s−1. Additionally, the effect of concentration and temperature on the complexation reaction was investigated. Apparent kinetic parameters of the complex formation of Fe(III) with caffeic acid were found as; pre-exponential factor A (−1.17 min−1), enthalpy of activation (ΔH°)# (−2188 J mol−1), entropy of activation, (ΔS°)# (−7.34 J mol−1 K−1) and Gibbs free energy of activation, (ΔG°)#(−0.68 J). The apparent activation energy of the complexation reaction was evaluated to be 289.29 J mol−1 which is consistent with the chemistry of Fe(III) with polyphenols which are supposed to mimic the interaction of Fe(III) with transferrin in biological media. Various theoretical parameters of the studied complex such as hardness, electronegativity, softness, total energy, dipole moment and point group symmetry were calculated employing Density functional theory (DFT) and found as 0.04465, 0.2130, 22.39, 0.5201 × 10−8 eV, 15.13 Debye, and C1, respectively. Graphical Abstract Unlabelled Image Highlights • The aim of the present work was to study the kinetics of the complexation of Fe(III) with caffeic acid in aqueous solution at pH 9.0. • The complex was characterized by IR, UV-Vis spectroscopy and FE-SEM techniques. • The complexation reaction was found to be a first-order with rate constants for k 1 (formation) 4.7×10-3 sec-1. • Additionally, the effect of concentration and temperature on the complexation reaction was investigated. • Apparent kinetic parameters of the complex formation of Fe(III) with caffeic acid were evaluated. • The apparent activation energy of the complexation reaction was evaluated to be 289.29 J mol-1 which is consistent with the chemistry of Fe(III) with caffeic acid. • Various theoretical parameters of the studied complex were also investigated. [ABSTRACT FROM AUTHOR]

Highlights • Stability and phase behavior of chitosan/casein complexes were systematically studied for the first time. • Bridging flocculation was determined to be highly dependent on the charge density of polysaccharide. • The complexation granted casein with higher stability over wider range of pH. • The effect of pH and ionic strength on the complexation behavior was thoroughly investigated. Abstract The interaction between polysaccharides and proteins has attracted great interests and the phase behavior and colloidal properties of complexes between chitosan, a positively charged polysaccharide, and proteins still need careful investigation. Here, we use chitosan/casein as model system and monitor their complex size, zeta-potential, light scattering intensity and phase behavior as functions of chitosan deacetylation degree, pH and ionic strength. Chitosan flocculates casein at low polysaccharide concentrations, while stabilizes casein at moderate to high concentrations. Such flocculation and stabilization ability are dependent on the linear charge density of chitosan, where high charge density chitosan saturates casein surface charge and stabilizes the complexes at lower polysaccharide concentration. The complexes are stable at acidic pH where chitosan is highly protonated and the addition of NaCl leads to the reduction in both size and zeta-potential and facilitates complex aggregation. The phase maps are constructed to provide guidelines for further studies on chitosan/casein and other chitosan/protein complexes. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Selective adsorption and regeneration of adsorbents are great challenges for fluoride removal in drinking water. In this study, a NiAl-layered metal oxide (NiAl-LMO) electrode was successfully prepared and used as an electro-adsorption electrode. With its structural memory effect for anions and high specific capacitance of 575 F·g−1, the NiAl-LMO electrode exhibits capacitive deionization performance. The maximum adsorption capacity of F− by the electrode reached 49.28 mg/g, which was 4 times that of Cl− and 2 times that of SO 4 2−, respectively. The good selectivity for F− electrosorption was ascribed to the high electronegativity of F− and the complexation between F− and hydroxyl aluminum groups. The electrode material has good stability and can be regenerated easily by applying a reverse voltage. After 10 cycles, the F− adsorption rate by the NiAl-LMO electrode was 94. 4% of the initial adsorption rate. The applied voltage enhanced the selectivity of F− adsorption by the NiAl-LMO electrode, and this electrosorption process was mainly dominated by electrical double layer adsorption. Under the conditions of 1.0 V and pH 7, the electrode showed a maximum adsorption efficiency of 73.5%. [ABSTRACT FROM AUTHOR]

Graphical abstract Enhanced extraction of rare earths by using ionic liquids originate from the synergism of Hofmeister bias and the complexation behavior of salt anions. Abstract Separation and recycling of rare-earths using ionic liquids as extractant are becoming a promising approach to replace traditional volatile organic solvents in recent years. Generally, the addition of some special salts could improve the extraction efficiency of rare-earths by numerous non-functional ionic liquids. However, knowledge behind the nature of the salt effect is limited. Here, we found that the enhancement in the extraction of rare-earth ions, Pr3+ ions, using non-functional ionic liquid, [A336][NO 3 ] (Tricaprylmethylammonium nitrate) was driven by the synergism of Hofmeister bias and complexation behaviors of salt anions with Pr3+ ions. Molecular dynamic simulations offered a new insight into the interaction mechanism of the ionic liquid with Pr3+ ions at liquid/liquid interface. It was revealed that salt anions could perform as a bridge to connect Pr3+ ions and the ionic liquid, so that promoted the extraction of Pr3+ ions. Therefore, the strong complexation ability of salt anions with Pr3+ ions and poor hydration of salt anions faciliated the transport of Pr3+ ions across liquid/liquid interface. [ABSTRACT FROM AUTHOR]

Although computer-aided drug design has greatly improved over time, its application in the pharmaceutical industry is still limited by the accuracy of association constant (Ka) predictions. Towards improving this situation, the Statistical Assessment of the Modeling of Proteins and Ligands (SAMPL) is a series of community-wide blind challenges aimed to advance computational techniques as standard predictive tools in rational drug design (https://en.wikipedia.org/wiki/SAMPL%5fChallenge). As an empirical contribution to SAMPL6, we report here the Ka and thermodynamic parameters (∆G, ∆H, - T∆S) of eight guests binding to two hosts (OA and TEMOA) using ITC. Both hosts contain a unique, well-defined binding pocket capable of storing guests with up to ten non-hydrogen atoms, whilst the selection of amphiphilic guests contain a range of saturated and unsaturated substituents. The thermodynamic data from this study will allow the challenge participants of SAMPL6 to test the accuracy of their computational protocols for calculating host-guest affinities. [ABSTRACT FROM AUTHOR]

The host-guest complexations of fifteen protonated azaspirocyclic, oxa,azaspirocyclic, and diazaspirocyclic guests, three-dimensional analogues of morpholinium, piperidinium, and piperazinium cations, respectively, with cucurbit[7]uril (CB[7]) were investigated using 1H NMR spectroscopy in an acidic aqueous solution. The host-guest stability constants (KCB[7]) for the protonated spirocyclic guests were determined to range from 104-1011 M−1. The relative stability constants have been analyzed in terms of ring sizes and molecular volume (packing coefficient), and the presence and positions of additional oxygen and quaternary nitrogen heteroatoms. The larger the size of both the rings of the guest molecules the higher the observed binding constants for these guests with CB[7]. The largest values for KCB[7] were found for 1- and 2-azaspiro[3.5]nonane, 2- and 8-azaspiro[4.5]decane, and 2-azaspiro[5.5]undecane, when the guest contained 9-11 heavy atoms. Adding oxygen heteroatoms decreased the binding constants by 2-3 orders of magnitude for the azaspirocyclic guests. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Types of copper(II) complexes immobilized on silica and their stability constants. • Heterogeneous titration for classification of dynamic equilibria in a wide pH range. • XPS and EPR show strong interactions between Cu(II) and immobilized ligand on surface. Abstract Identification of the copper(II) ions complexes deposited on the amorphous silica surface was conducted using four different research techniques. The potentiometric titration in heterogeneous system was used to establish the forms of complexes with ligands immobilized on the surface. The types of Cu(II) complexes depend on the pH value. In the pH range 4–11, the presence of the following four types of Cu(II) complexes was evidenced: CuHSGL, CuSGL, Cu(SGL) 2 , and Cu(SGL) 2 (OH). Their stability constants were found to be log β CuHSGL = 14.01, log β CuSGL = 7.51, log β Cu(SGL)2 = 14.12, and log β Cu(SGL)2(OH) = 4.84 for I = 0.1 M KNO 3. These complexes were characterized by X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and UV–Vis methods. According to the XPS results, close to pH 6, the partly protonated ligand can additionally form surface ion compounds of the type [R-NH 2 + (CH 2) 2 NH 2 ][NO 3 –]. EPR permitted determination of the spin-Hamiltonian, showing that Cu(II) ion was in the ground state d x 2 -y 2, and the Cu(II) ions symmetry can be described as that of deformed tetragonal octahedrons. UV–Vis measurements in a flow cell confirmed the course of reaction in the heterogeneous system between Cu(II) and diamine ligand, N-(2-amineethyl-3-aminepropyl)trimethoxysilane, immobilized on the surface of amorphous silica gel. [ABSTRACT FROM AUTHOR]

Abstract Phosphorus removal is essential to avoid eutrophication in water bodies. Layered double hydroxides (LDHs) are widely used to scavenge phosphate through intercalated ion exchange or surface complexation. Moreover, LDHs have attracted increasing attention as electrode modifiers for supercapacitors. Researchers have begun to re-delve the electrosorption technology according to the fundamental principle of electrical double layers. Herein, we propose a new phosphate removal method inspired by the adsorption characteristic and electrical double-layer capacitive properties of LDHs through electrosorption via capacitive deionization. We present a series of experiments to study the enhanced phosphate removal under an electric field via multiple mechanisms on the MgAl-LDHs/AC electrode. The uptake of phosphate by MgAl-LDHs/AC was investigated as a function of phosphate concentration, applied voltage, electrode materials, and temperature. The MgAl-LDHs/AC electrode possessed a salt removal capacity of 67.92 mg PO 4 3−·g−1 (1.2 V, 250 mg·L−1 KH 2 PO 4 , 30 °C). The electrosorption kinetics of phosphate ions onto the capacitive deionization electrode followed the pseudo-second-order kinetics model rather than the pseudo-first-order kinetics model. Furthermore, the adsorption isotherms of phosphate on the MgAl-LDHs/AC electrode fitted the Freundlich model better than the Langmuir model. The proposed method could be used for phosphate removal. Graphical abstract Unlabelled Image Highlights • A new phosphate removal method was proposed under electrostatic field. • Phosphate removal capacity reaches 67.92 mg PO 4 3−·g−1 for 250 mg·L−1 KH 2 PO 4 solution. • Influence of different experimental parameters on the electrosorption was examined. • Multiple mechanisms exist in electrosorption of phosphate on MgAl-LDHs/AC electrode. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Higher Cr(VI) removal and longer longevity were achieved in synergistic system. • The synergism contained HFB-ZVI/Fe 3 O 4 composite and Na 2 EDTA complexation. • The composite strongly captured Cr(VI) by electrostatic attraction and exchange. • Na 2 EDTA complexation retarded passivation and produced more reactive sites. • Na 2 EDTA recovery and column regeneration were successfully demonstrated. Abstract The application of zero-valent iron (ZVI) for Cr(VI) removal often presents limitations due to its easy passivation. In this study, a column packed with hydroxyl-functionalized ball-milled ZVI/Fe 3 O 4 (HFB-ZVI/Fe 3 O 4) composite, assisted with Na 2 EDTA complexation, was developed to achieve sustainable treatment of Cr(VI)-containing wastewater. The results showed that at influent Cr(VI) concentration of as high as 50 mg/L, effluent Cr(VI) concentration below 0.5 mg/L was sustained for bed volume of as high as 1271 BV along with 2 g/L Na 2 EDTA concentration. Through the hydroxyl-functionalized treatment, FeOOH coating containing surface-adhering Fe(II) on the composite surface can be formed. Hydrolysis and auto-reduction of Fe(II)/Fe(III) species caused proton accumulation, resulting in remarkable attraction of anionic Cr(VI) via electrostatic interaction and exchange. Therefore, the reduction of Cr(VI) to Cr(III) was considerably enhanced. On the other hand, Na 2 EDTA complexation suppressed the growth of passivation layer and generated fresh corrosion products, thereby providing additional reactive sites for Cr(VI) removal. Additionally, Na 2 EDTA recovery and spent column regeneration were successfully proven. The remarkable effectiveness of Cr(VI) removal from actual electroplating wastewater confirmed the potential of the HFB-ZVI/Fe 3 O 4 composite-packed column and Na 2 EDTA assistance-coordinated system in full-scale application. [ABSTRACT FROM AUTHOR]

Abstract Waste activated sludge (WAS) contains many anionic functional groups which can interact with heavy metal ions through electrostatic action and complexation reactions. The transition metals adsorbed in WAS can catalyze sludge pyrolysis in anaerobic conditions and improve structural properties of organic matter. In this work, a multistage WAS utilization process for preparing the carbon-based Fenton-like catalysis materials is proposed. More specifically, WAS is firstly used as an adsorbent for heavy metals (Cu and Ni) removal, and then complexes are converted into heterogeneous Fenton-like carbon-based catalysts through oxygen-free pyrolysis. The mechanisms of interactions between extracellular polymeric substances (EPS) and metals are investigated, and the physicochemical properties of sludge-based carbons (SBC) are comprehensively characterized using varies techniques. It is found that WAS is an excellent adsorbent for Cu and Ni removal, which is mainly due to the coordination and electrostatic interactions between EPS and heavy metals. Cu and Ni adsorbed in WAS significantly improved the porous structure of SBC. Both adsorption and catalytic oxidization of Cu/Ni-SBC contribute the removal of E2 in real wastewater. The E2 removal mechanism is explored by electron-spin resonance spectroscopy (ESR) analysis, and it is found that both of .O 2 − and .OH radicals are responsible for E2 degradation in Cu(II)-SBC-H 2 O 2 , while .O 2 − radicals contributes to E2 degradation in Ni(II)-SBC-H 2 O 2 system, so the former performed better than the latter in total removal of E2. Besides, Cu(II) and Cu(I) are both formed in Cu(II)-SBC during the oxidation process, while only Ni(II) is found in the Ni(II)-SBC-H 2 O 2 process, confirming that different catalytic oxidation reactions are occurred in the Cu(II)-SBC-H 2 O 2 and Ni(II)-SBC-H 2 O 2 processes. This study facilitates a great strategy to the sludge multi-stage circulating utilization and a better understanding about the role of the Cu/Ni existed in SBC during the estrogens removal process. Graphical abstract Image 1 Highlights • Proposed multistage WAS process to initiate carbon-based Fenton-like catalysis for the first time. • Cu(II)/Ni(II) adsorbed in sludge improved the porous structure of SBC materials. • The coordination interactions mechanisms between EPS and heavy metals were determined. • The combination of Cu(II)/Ni(II) and sludge carbon (SBC) enhanced E2 removal from wastewater. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Self-diffusion (D w) and D OH coefficients comparable up to 470 K. • Above 470 K D OH by 30% lower due to enhanced complexation of OH with H 2 O. • Continuous lifetime ∼10−14 s calculated for both H-donor and H-acceptor bond. • Intermittent lifetime 4 ps (373 K) drops to 1 ps (673 K) exceeding translational time. • Conclusions on OH aq translational dynamics depend on model potential used. Abstract MD simulations using flexible models were performed to show how velocity autocorrelation functions, diffusion (D OH) and self-diffusion (D w) coefficients, continuous and intermittent lifetimes of H-donor and H-acceptor bonds depend on: i) transformations in the hydrogen-bond network (HBN) of water below the critical point, and ii) decreasing density at the supercritical isotherm (∼670 K). Contrary to simulations neglecting short-range hydrogen-oxygen interactions, we show that complexation of OH aq with H 2 O is enhanced by breakage of the continuous HBN, resulting in the increase of OH aq hydrodynamic radius and the D OH values smaller than D w by 30%. Difference between D OH and D w increases to 65% at 670 K below the critical density. It is explained by enhanced aggregation of water molecules around OH aq , earlier recognized as the self-trapping mechanism. Except near-ambient conditions, the intermittent lifetime of H-bonds is longer than the translational time, indicating that OH aq is complexed with water and moves as a molecular aggregate. [ABSTRACT FROM AUTHOR]

Abstract Fluoride (F−) pollution is a worldwide issue. Coagulation with aluminum (Al) salts is an efficient and economical method for the removal of F−. However, due to the strong complexation between Al3+ and F−, the residual F− and Al after coagulation usually exceed the limits. Zirconium (Zr) coagulants have drawn increasing attention due to their excellent flocculation ability for organic matter. In this work, the performance and mechanism of ZrCl 4 coagulation for F− removal were investigated with the widely used Al 2 (SO 4) 3 as a reference. The optimum pH range is 4.0–6.0 for ZrCl 4 and 8.0–10.0 for Al 2 (SO 4) 3. ZrCl 4 was superior to Al 2 (SO 4) 3 for F− removal as the initial F− concentration was less than 30.0 mg L−1. Coexisting substances at environmental concentration levels showed negligible effects on F− removal by ZrCl 4. Besides the better F− removal, another advantage of ZrCl 4 over Al 2 (SO 4) 3 was the much lower residual metal concentration in the pH range of 4.0–11.0. The hydrolysis of Al 2 (SO 4) 3 was significantly inhibited due to the formation of Al-F complexes while the hydrolysis of ZrCl 4 was not influenced even under strongly acidic conditions. Therefore, F− removal by Al 2 (SO 4) 3 was mainly achieved by preliminary complexation between Al3+ and F− and subsequent hydrolysis and polymerization of these complexes, while adsorption onto hydrolysates and ion exchange with surface hydroxyl groups were the main ways of F− removal by ZrCl 4. The work here provides a new method for F− removal and may shed light on the application of Zr coagulants for other pollutants. Graphical abstract Image 1 Highlights • ZrCl 4 exhibited a better coagulation performance than Al 2 (SO 4) 3 for F− removal. • The strong complexation with F− is an unfavorable characteristic in Al coagulation. • ZrCl 4 led to a much lower residual metal concentration as compared with Al 2 (SO 4) 3. • Phosphate, arsenate and turbidity could be effectively removed by ZrCl 4 coagulation. • Adsorption onto positively charged hydrolysates played a key role in defluorination. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Binding of group IA/IIA cations to N -phenylaza-15-crown-5 substituted Schiff bases. • Spontaneous complexation process in the gas phase for all metal cations. • Spontaneous complexation process for the smaller cations in acetonitrile. • More negative ΔG values for the complex formation with group IIA metal cations. Abstract N -Phenylaza-15-crown-5 containing Schiff bases act as excellent ligands for alkali and alkaline-earth metal ions. The complex formation ability of two differently N -phenylaza-15-crown-5 substituted Schiff bases has been investigated using density functional theory methods. The structures of the ligands and of the respective complexes with alkali and alkaline earth metal ions have been optimized and the thermodynamic parameters of the complex formation reactions have been determined. According to the obtained results there is a rough correlation between the metal cation radius and ΔG values in the gas phase and in acetonitrile solution: the smaller the cationic radius is, the more thermodynamically favorable is the complex formation. The results for the Gibbs free energy of the complex formation reaction of these ligands with seemingly ordinary structure with IA and IIA group metal ions indicate a spontaneous and energy-favorable process in the gas phase (for all metal cations) and in the acetonitrile environment (for the smaller ones). [ABSTRACT FROM AUTHOR]

Graphical abstract A pictorial representation of two benzo crown ethers assembling together to accommodate a potassium ion to form 2:1 ligand-metal ion complex. The cation is held in the cavity by ion-dipole interactions. The coordination number of the potassium ion is ten. Complexation enhanced fluorescence produced by suppression of PET mechanism is masked by FRET. Highlights • Complexes of two crown ethers, benzo-15-crown-5 and dibenzo-15-crown-5, were prepared with potassium halides in acetonitrile and characterized by FTIR, UV, ESI-MS, 1H NMR and 13C NMR techniques. • Fluorescence studies showed that the fluorescence emission intensity is a residual value after suppression of photoinduced electron transfer (PET) mechanism and energy resonance transfer (FRET) mechanism operative in complexes of benzo-15-crown-5 and dibenzo-15-crown-5. • These complexes can be used as FRET based sensors for potassium ions. Abstract Cation recognition plays a vital role in defining advanced functions of macromolecules in nature. An example of such an interaction is the action of a natural antibiotic, valinomycin, that behaves as a potassium ionophore. It encages the cation to transport it across a cell membrane and easily releases it inside the cell. Macrocyclic complexes of some crown ethers mimick alkali ion interactions with natural ionophores. We have synthesized complexes of two crown ethers namely benzo-15-crown-5 (2,3,5,6,8,9,11,12-octahydrobenzo[ b ][1,4,7,10,13]pentaoxacyclopentadecine) and dibenzo-15-crown-5 (6,7,9,10,17,18-hexahydrodibenzo[ b,h ][1,4,7,10,13]pentaoxacyclopentadecine with potassium halides (fluoride, chloride, bromide and iodide) in acetonitrile and characterized them by IR, UV, ESI-MS, 1H NMR and 13C NMR techniques. The effect of the anion on the stability of the complexes was observed by 1H NMR studies. The alkali metal ion is held to the oxygen donor atoms of the macrocyclic ring by ion-dipole interactions. The potential of the small ring oxacrown ethers, benzo-15-crown-5 and dibenzo-15-crown-5, to act as probes for potassium ions in dilute solutions (4.1 × 10−4 M) was investigated by recording the variation in the fluorescence spectra of benzo-15-crown-5 and dibenzo-15-crown-5 on complexation with potassium fluoride in acetonitrile and chloroform. The rigidity of the macrocyclic ring and proximity of fluorophore units affected the fluorescence intensity of the complexes. [ABSTRACT FROM AUTHOR]

Graphical abstract Two new symmetrical Schiff base ligands were derived from condensation of new synthesized polyamine (A) and 2-hydroxybenzaldehyde (H 2 L1) or 2-hydroxy-3-methoxybenzaldhyde (H 2 L2). Six macroacylic Schiff base complexes were prepared by direct reaction of H 2 L1 or H 2 L2 and Mn(II), Zn(II) and Cd(II) metal ions in equimolar ratios. The crystal structure of H 2 L1 was confirmed by single crystal X-ray analysis. A competitive 7Li NMR manner was used to probe the complexation of Mn2+, Zn2+and Cd2+ ions with (H 2 L1) and (H 2 L2) in the same solvent systems. Cytotoxic and antibacterial properties of complexes were also investigated. Abstract In this work, two new symmetrical, potentially N 6 O 2 coordinating, macroacyclic Schiff base ligands (H 2 L1 and H 2 L2) were derived from the condensation of a newly synthesized polyamine, 2,2′-(ethane-1,2-diylbis(piperazine-4,1-diyl))bis(ethan-1-amine) (A), with 2-hydroxybenzaldehyde and 2-hydroxy-3-methoxybenzaldhyde respectively. Six macroacylic Schiff base complexes were prepared by direct reaction of H 2 L1 or H 2 L2 with Mn(II), Zn(II) or Cd(II) metal ions in equimolar ratios. The products were characterized by several physicochemical measurements. As well, the crystal structure of H 2 L1 was confirmed by a single crystal X-ray structural analysis. Competitive 7Li NMR experiments were used to probe the complexation of Mn2+, Zn2+ and Cd2+ ions with (H 2 L1) and (H 2 L2) in both acetonitrile and methanol. The stabilities of the final complexes were found to be in the order M–(H 2 L1) > M–(H 2 L2) and Cd2+ > Zn2+ > Mn2+. The cytotoxic and antibacterial properties of these complexes were also investigated. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Cu nanoparticles were prepared in successive stages: preparation of the Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 MNPs), coating of the Fe 3 O 4 MNPs with tetraethyl orthosilicate (Fe 3 O 4 @SiO 2), functionalization of Fe 3 O 4 @SiO 2 with 3-chloropropyltrimethoxysilane (CPTMS) and 4-amino-1,2,4-triazole (AT) ligands (Fe 3 O 4 @SiO 2 @CPTMS@AT), and the complexation of Fe 3 O 4 @SiO 2 @CPTMS@AT with CuCl 2 (Fe 3 O 4 @SiO 2 @CPTMS@AT@Cu). The obtained Cu nano-catalyst was then used for the synthesis of diverse tetrazoles from the reaction of various amino acids with sodium azide and triethyl orthoformate (TEOF) in ethanol at 80 °C. [ABSTRACT FROM AUTHOR]

Abstract A clay mineral (synthetic hectorite) was complexed with titanium dioxide (anatase with the average particle size of 20 nm) as a film on a glass substrate for photocatalyst application. The mass ratio of the hectorite to the anatase was optimized to be 1(hectorite):10(anatase) to obtain homogeneous coatings. The photocatalytic decolorization of organic dyes (methyl orange and methylene blue) by UV irradiation was examined as a model reaction to find a synergy effect of the hybridization, an efficient methylene blue decomposition in an acidic solution. Graphical abstract Unlabelled Image Highlights • A clay mineral was complexed with a titanium dioxide particle (anatase with the average particle size of 20 nm) as a film. • The smectite-titania hybrid film on a glass substrate was used as photocatalyst. • The mass ratio of the hectorite to the anatase was optimized to be 1(hectorite):10(anatase) to obtain homogeneous film. • The photocatalytic decolorization of organic dyes (methyl orange and methylene blue) by UV irradiation was examined. [ABSTRACT FROM AUTHOR]

Open cell polyurethane foams coated with mussel‐inspired polydopamine can be used as support for borohydride anions through their complexation by the catechol groups of the polydopamine layer. This strong interaction prevents borohydride hydrolysis and oxidation, and based on the redox mediator properties of polydopamine, the so‐functionalized polydopamine‐coated open cell polyurethane foams can act as efficient and reusable soft structured materials for the reduction of methylene blue in aqueous solution without additional sodium borohydride (NaBH4). Very low amounts of released boron sub‐products and very small potential of hydrogen (pH) increase are observed in comparison to previous processes using dissolved NaBH4. This considerably reduces the environmental impact of the reducing structured material on the treated wastewater compared to the latter. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 329–335, 2019 [ABSTRACT FROM AUTHOR]

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Graphical abstract The reactions of cyclometallated PtIV compounds with biological thiols and methionine have been studied; the reduction is followed by a PtII substitution process. The reduction process, via reductive elimination of a ClSR molecule, has been found rate limiting in all cases, thus explaining the lack of reactivity with methionine. Highlights • PtIV cyclometallated compounds are reduced to PtII and substituted by thiols. • The reduction process involves an attack of thiolate to one of the chlorido ligands. • The PtIV complex structure is maintained before reduction. Abstract The kinetics of the reaction of [PtIV(4X- C ph , N , N')Cl(Y) 2 ] complexes (2-X-Y) (X = Cl or F and Y = OH or Cl) with biological thiols (glutathione, cysteine, thiolactic acid) and methionine, has been monitored by UV–Vis spectrophotometry. The reactions have been followed at varying pHs and chloride concentrations (within the physiological range) and different temperatures and pressures. The bis -chlorido derivatives, 2-X-Cl , have been found to react with cysteine, glutathione and thiolactic acid, while the bis -hydroxido 2-X-OH derivatives are not reduced due to the high potential of the PtIV/PtII pair, as measured in aqueous solution. The lack of reactivity of methionine is related with its tioether nature preventing deprotonation of the S donor. In all remaining cases, two consecutive reaction steps have been found to occur. For cysteine the two steps can be kinetically resolved, the first step being neatly related to a PtIV to PtII reduction and the second step corresponding to the substitution of the remaining Cl− ligand by cysteine. The nature of the second step has been also confirmed by ESI-MS, as well as by the associative character of the activation parameters determined (low Δ H ╪ and very negative Δ S ╪ and Δ V ╪). For glutathione and thiolactic acid, the rate and thermal and pressure activation parameters for the reduction step has been found similar to that obtained for the reaction with cysteine, but the substitution step could not be resolved kinetically. The substitution step, as measured from the reduced [PtII(4X- C ph , N , N')Cl] complex, is faster than the reduction process, and also much faster than that observed for the reaction with cysteine. In both cases the final product resulting for the reduction reactions corresponds thus to the final substituted complex as found for the reaction with cysteine. [ABSTRACT FROM AUTHOR]

Graphical abstracts Calixarenes and coordination polymers: a promising union for future MOFs. Abstract 25,27-bis(methoxycarboxylic acid)-26,28-dihydroxycalix[4]arene (calixH2), so call here calix[4]arene dimethoxycarboxylic acid, was investigated for its ability to build metal–organic frameworks. When reacted with zinc or manganese chloride in DMF and deprotonated with trimethylamine it gives Zn (1) and Mn (2) coordination compounds. These crystallize in the triclinic P -1 space group and are isostructural as shown by X-ray diffraction on single crystals. The crystal structures evidence the coordination of calix[4]arenedimethoxycarboxylic acid through the carboxylate groups. This makes a 1D coordination polymer running along the c axis direction in which [MII 2 (calix) 2 (H 2 O) 3 (DMF) 2 ] (M = Zn or Mn) neutral units are connected. Last step refinements of the crystal structure reveal a lot of residual electron density which was ascribed to uncoordinated disordered water and DMF molecules. This was treated with the SQUEEZE routine of the program PLATON from which the solvent accessible voids per unit cell volume was calculated to be 24.5% for compound 1 (Zn) and 24.9% for compound 2 (Mn). Complementary differential thermal analyses (DTA) combined with thermogravimety analysis (TGA) and mass spectrometry (MS) are in agreement with large amount of incorporated and non-coordinated water and DMF molecules. Adsorption isotherms of N 2 measured for compound 1 do not show any significant porosity. The temperature dependence of the magnetic susceptibility (χ) of compound 2 evidences antiferromagnetic interactions and was best fitted with a weak antiferromagnetic exchange coupling between the manganese(II) ions J = − 1.5 cm−1 and small antiferromagnetic inter-dinuclear interactions zJ = − 1.2 cm−1 (g = 2.02). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • MGO showed the best adsorption capacities for TC, Cd(II) and As(V) among three magnetic graphene nanomaterials. • Adsorption behaviors of MGO in three different types of binary systems were systematically studied. • Mutual effects of TC and Cd(II) in the simultaneously added system were negligible. • Adsorption of As(V) was significantly suppressed in the presence of TC. • Cd(II) and As(V) were co-adsorbed by MGO via electrostatic attraction and formation of type A ternary surface complexation. Abstract The adsorption of tetracycline (TC), cadmium [Cd(II)] and arsenate [As(V)] onto magnetic graphene oxide (MGO), magnetic chemically-reduced graphene (MCRG) and magnetic annealing-reduced graphene (MARG) was investigated to understand the adsorption properties and molecular mechanisms. The adsorption of three contaminants was pH-dependent and the adsorption capability followed the order of MGO > MCRG > MARG, and hence MGO was selected to systematically study the adsorption behaviors in three different types of binary systems. The maximum adsorption capacities of MGO were 252 mg/g for TC, 234 mg/g for Cd(II) and 14 mg/g for As(V). The superiority of MGO was mainly attributed to its high dispersibility, thin nanosheets and various O-containing functional groups. In addition to H-bonding and π–π interactions, the strong adsorption of TC onto MGO was mainly due to the n–π electron-donor–acceptor (EDA) effect, with the maximum adsorption around pKa of TC. The mutual effects of TC and Cd(II) in the simultaneously added system were negligible. Adsorption of As(V) was significantly suppressed in the presence of TC, whilst As(V) hardly affected TC adsorption. The adsorptions of Cd(II) and As(V) in the co-adsorption system were increased by 65% and 30%, respectively. This synergistic effect resulted from the electrostatic attraction and the formation of type A ternary surface complexation. These new insights were valuable for elucidating the interaction mechanisms and designing novel adsorbents for traditional and emerging pollutions in practical application. [ABSTRACT FROM AUTHOR]

Abstract Sulfonated poly(phenylene) (sPP) thermal stability, physical properties, and gas transport characteristics were evaluated as a function of ion-exchange capacity (x = IEC), and counter-ion type (M = H+, Cs+, Na+, Mg2+, and Al3+). Counter-ion substitution with its sulfonated groups produced Δv (SO 3 -) vibrational shifts that were related to ion type and valence observed using FTIR. Increasing IEC and counter ion complexation strength within sPP led to greater density and reduced fractional free volume (FFV). sPP x -M exhibited a single thermal degradation step greater than 550 °C that decreased with increasing IEC. Unsulfonated poly(phenylene) (PP) had a glass transition at 391 °C, which shifted to 420 °C upon sulfonation. Thermal stability and mechanical properties increased with counter-ion type in the following order: sPP2.5-Cs+ < sPP2.5-Na+ < sPP2.5-Mg2+. However, decreased thermal stability and physical properties were observed using Al3+ as a counter-ion (sPP2.5-Al3+). He, H 2 , CO 2 , N 2 , O 2 and CH 4 permeability decreased within sPP2.5-M based upon counter-ion type, size, and valence. Larger CO 2 and H 2 molecules were more permeable than He, which revealed a more complex transport process was occurring within sPP2.5. Metal-ion complexation with sPP2.5 significantly reduced CO 2 and H 2 permeability. PP possessed high CO 2 permeability (152 Barrers) with moderate CO 2 /CH 4 selectivity (12.6). sPP2.5-Na+ (IEC = 2.5 meq/g) had a CO 2 /CH 4 selectivity of 71.3, and counter-ion substitution to create sPP2.5-Cs+ increased CO 2 /CH 4 selectivity by 2 3%. Gas solubility and diffusivity decreased with increasing IEC and metal-ion complexation strength. sPP x -M had tunable ideal gas permselectivity that was largely a function of sulfonate group concentration and counter-ion type. Graphical abstract fx1 Highlights • Sulfonated poly(phenylene) (sPP) physical, thermal, and gas transport properties were dependent upon counter-ion size and type. • Sulfonate group Δv (SO 3 -) shifted to higher energy based upon ion size and valence. • sPP thermal (> 560 °C) stability increased using Cs+, Na+, and Mg2+. • sPP films underwent metal-ion complexation and ionic crosslinking observed with DMTA. • sPP complexed with Al3+ led to a simultaneous improvement in O 2 /N 2 selectivity and O 2 permeability. [ABSTRACT FROM AUTHOR]

Abstract Ion selective membrane (ISM) electrodes are widely used for selective ion sensing applications. Recently, new modalities have emerged whose operation involves active electrical polarization of the media, and current theoretical models are unsuitable to predict their behavior beyond near-equilibrium conditions. Here, we apply numerical modeling of physicochemical transport in such systems to study mechanisms of interfacial ion transfer and their role in limiting processes. Importantly, our analysis suggest that membrane-phase complexation (MC) has strong merits as a replacement for interfacial complexation (IC) in theoretical treatments. For our purpose, we have developed a highly detailed model based on Nernst–Planck–Poisson (NPP) with kinetic reactions of first-order. The solutions were derived in terms of logarithmically transformed concentration variables, allowing us to input experimentally determined stability coefficients. A unique process, referred to here as the reaction boundary layer (RBL), is a characteristic of MC, and we found it could have a significant impact on current–voltage (I–V) characteristics and transfer selectivity. Together with other well-known processes such as electrically driven diffusion, the RBL dictates the limits of ISM electrical polarization. Using our model, we demonstrate that operating outside these limits results in ingress of interfering ion species and concurrent loss of transfer selectivity. Highlights • Membrane complexation has strong merits as the intrinsic mechanism of interfacial ion transfer. • A reaction boundary layer effectively produces an intrinsic ISM current limit. • ISM over-limiting processes generally result in loss of transfer selectivity for the primary ion. [ABSTRACT FROM AUTHOR]

Highlights • High-resolution sampling showed seasonal variations in dissolved and labile Zn. • Algal blooms reduced concentration of dissolved Zn by algal assimilation in summer. • Concentration of dissolved Zn decreased via Mn oxides adsorption of Zn in winter. • Mn oxides reduction and DOM complexation increased Zn mobilization in other seasons. Abstract To assess zinc (Zn) pollution risk from sediments, this study investigated the monthly changes of dissolved Zn and labile Zn in sediment-overlying water profiles in a eutrophic bay (Meiliang Bay) of Lake Taihu (China) using high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) at a 4 mm vertical resolution. In February and March, Mn oxides reduction caused high concentrations of DGT-labile Zn (14 ∼ 235 μg L−1), as evidenced by the significant correlation between DGT-labile Zn and DGT-labile Mn in sediments. In June and July, algal blooms reduced concentrations of dissolved Zn via algal assimilation. From August through October, concentrations of dissolved Zn in overlying water (338 ∼ 1023 μg L−1) exceeded the water quality limit for fisheries in China (100 μg L-1). This was attributed to reductive dissolution of Mn oxides in sediments caused by algal degradation followed by complexation of dissolved organic matter (DOM), which was identified in a simulated algal bloom experiment. In the winter, decreased Zn mobility was mainly attributed to adsorption by Mn oxides. It was concluded that enhanced Zn pollution risk from sediments is worthy of concern especially during algal degradation in eutrophic lakes. [ABSTRACT FROM AUTHOR]

Abstract Due to the high sensitivity to alterations in microenvironment polarity of macromolecules, pyrene and its derivatives have long been applied in biosciences. Human serum albumin (HSA), besides its numerous physiological functions, is the main responsible by transport of endogenous and exogenous compounds in the circulatory system. Here, a comprehensive study was carry out to understand the interaction between HSA and the pyrene derivative 1-pyrenesulfonic acid (PMS), which showed a singular behaviour when bound to this protein. The complexation of PMS with HSA was studied by steady state, time-resolved and anisotropy fluorescence, induction of circular dichroism (ICD) and molecular docking. The fluorescence quenching of PMS by HSA was abnormal, being stronger at lower concentration of the quencher. Similar behaviour was obtained by measuring the ICD signal and fluorescence lifetime of PMS complexed in HSA. The displacement of PMS by site-specific drugs showed that this probe occupied both sites, but with higher affinity for site II. The movement of PMS between these main binding sites was responsible by the abnormal effect. Using the holo (PDB: ID 1A06) and apo (PDB: ID 1E7A) HSA structures, the experimental results were corroborated by molecular docking simulation. The abnormal spectroscopic behaviour of PMS is related to its binding in different regions in the protein. The movement of PMS into the protein can be traced by alteration in the spectroscopic signals. These findings bring a new point of view about the use of fluorescence quenching to characterize the interaction between albumin and ligands. Graphical Abstract Unlabelled Image Highlights • Fluorescence quenching of 1-pyrenesulfonic acid (PMS) by albumin (HSA) is abnormal. • The binding site occupied by PMS in HSA determines the efficiency of quenching. • The abnormal effect is also observed by circular dichroism and time-resolved fluorescence. [ABSTRACT FROM AUTHOR]

Abstract A thymine moiety as ion binding accepter was introduced into asymmetric squaraine fluorophore by amide coupling reaction to develop a new thymine-squaraine based fluorescent chemosensor (SQ). Its detection ability towards heavy metal ions was investigated by UV–vis and fluorescent spectrometry. The results showed that the sensor had high selectivity towards Cd2+ over the other metal ions in aqueous media. Moreover, it was shown that the turn on fluorescence signal occurred in the present of high concentration of cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) solution which resulting in deaggregations of SQ. The stoichiometric ratio was determined by Job's plot analysis as 1:1 and the binding constant as 2.03 × 103 M−1 for the complex between Cd2+ and SQ was further calculated by the Benesi-Hilderbrand plot. The complexation mechanism was proposed according to ESI-MS and NMR results. The following DFT calculation fully supported that the detailed coordination mode of Cd2+ and SQ went through six-membered carbonyl oxygen and the C O group in the amide chain. Finally, the SQ sensor was successfully applied in waste water sample analysis. Graphical Abstract A new thymine-squaraine based turn on fluorescent probe has been developed for detecting Cd2+ ions on CTAB controlled squaraine aggregation. Unlabelled Image Highlights • A new near infrared thymine-squaraine based chemosensor SQ has been synthesized for Cd2+ detection. • 5-fold enhancements of turn on fluorescent signal for exclusive detection of Cd2+ can be observed. • The LOD was determined as 104 nM by tuning the surfactant controlled squaraine aggregation. • The chemosensor has proven to be applied in the industrial waste water analysis. [ABSTRACT FROM AUTHOR]

Abstract A chemometrically optimized procedure has been developed for the determination of isoprenaline (ISO) in the parent substance as well as in its respective pharmaceutical preparation. It is worth mentioning that although spectroscopic determination of Isoprenaline metal complexes has been described in literature, yet, no methods for the quantification of Isoprenaline with Samarium nor any other lanthanide metal have been reported. Fractional factorial design (FFD) was implemented in the initial screening procedure of the four designated factors, namely, reaction time (RT), metal volume (MV), pH and temperature (T) followed by Response Surface Methodology (RSM) optimization tool performed by the aid of Box Behnken design (BBD).The proposed techniques are based on a multivariate approach where a complexation reaction between Isoprenaline (ISO) and Samarium III (Sm3+) metal was exploited for the first time to synthesize novel fluorescence and absorbance probes of ISO-Sm. Maximum fluorescence intensity (Y1) as well as maximum absorbance (Y2) of the produced complex were attained at λ ex /λ em = 315/450 and λ 295 nm for spectrofluorimetric and spectrophotometric determinations, respectively, against blank solutions. Using assessment quality tools such as, Pareto charts, normal probability plots and statistical analysis of variance testing (ANOVA), significant factors were successfully indicated (p < 0.05). Furthermore, the proposed methods verified specificity and accuracy for the determination of Isoprenaline in its pure and pharmaceutical preparation using spectrofluorimetric (Technique A) and spectrophotometric (Technique B) techniques, respectively. Linearity was obtained in the range of (0.02–0.50 μg/mL) and (2–12 μg/mL) upon employing both techniques A and B, respectively. Furthermore, limit of detection (LOD) and limit of quantification (LOQ), were found to be 5.1877 ∗ 10−3 μg/mL, 0.01572 μg/mL and 0.5593 μg/mL, 1.6949 μg/mL, upon employing techniques A and B, respectively. Standard addition method was applied for both techniques. The analysis was successfully applied to the assay of pure powder and pharmaceutical dosage forms after which the corresponding mean recoveries were computed and were found to be in the range of 99.546%–100.257% (Technique A) and 99.872%–99.887% (Technique B) with RSD (<1). Graphical Abstract Unlabelled Image Highlights • Synthesis of novel Isoprenaline-Samarium chemosensor employing spectrofluorimetric and spectrophotometric techniques. • Fractional Factorial design for screening and Box-Behnken for optimization of factors. • Applying both techniques to determine ISO in pure powder and pharmaceutical dosage form. [ABSTRACT FROM AUTHOR]

Abstract The new series of divalent metal complexes [M(ox)(thy) 2 ]; M = Cd2+, Ni2+, Mn2+, Fe2+, Cu2+ and Zn2+, with mixed ligands oxalato (ox) and theophylline (thy) were prepared and characterized by molar conductance, FT-IR, UV–visible, 1H and 13C NMR and X-ray structure analysis. The crystal structure including the positions of the Zn (II) complex was determined by powder diffraction analysis using the FOX program. In the structure of zinc complex, the zinc (II) cations are octahedrally coordinated by two terminals N-bonding for theophylline ligand and by the O atoms of two oxalato bidentate ligand, resulting in discrete and slightly distorted octahedral complex. This complex was crystallized in the monoclinic system (C1 2/c1) space group and the unit cell parameters are a = 11.8364(1)Å, b = 4.5200(1)Å, c = 9.9942(1)Å with β (°) = 126.4770(2)°. The antimicrobial activity of the complexes was studied and the results of their tests show that the metal (II) complexes are more effective against several of bacterial and fungal strains. Graphical abstract Image Highlights • Six new complexes of general formula:[M (ox)(thy) 2 ] were synthesized. • The characterization of the synthesized complexes was investigated. • The octahedral structure of the obtained complexes was checked. • The antibacterial activity of the complexes was tested. [ABSTRACT FROM AUTHOR]

Highlights • Integrating the surface of Mg as a part of corrosion resistant coating via Mg-chitosan complexation process. • Chelating and depositing a CHI/BG composite coating onto Mg via a chemical conversion process at 75 °C. • CHI-based coating containing bioactive glass (BG) on Mg developed. • CHI-BG coatings exhibited bioactive properties upon immersion in SBF. Abstract Chitosan as a natural biopolymer was immobilized and chelating-deposited with and without bioactive glass (BG) onto Mg substrates by means of a chemical conversion process at 75 °C to provide anti-corrosion properties, good adhesion and biocompatibility. The aim of the present work was to integrate the surface of biodegradable Mg as a part of the corrosion resistant coating via metal-chitosan complexation process. The surface morphology and composition of the coatings were characterized by Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The results provided evidence of the formation of a chitosan coating as well as its chelating reaction and immobilization on magnesium by a chemical conversion process. The non-alkalization of the chitosan solution was ascribed to the protective layer of Mg (II)-chitosan complex, which inhibits the further migration of Mg ions. The in vitro bioactivity of both chitosan (CHI)-coated and chitosan/BG (CHI/BG)-coated surfaces in simulated body fluid (SBF) proved the complete retention of chitosan and BG on the magnesium substrates. The XRD analysis of the (CHI/BG) coating after 2 weeks immersion in SBF showed mainly the formation of magnesium hydrogen phosphate hexahydrate and undetected amorphous (Ca, Mg) phosphate. The present study represents a novel attempt to modify the surface of Mg by a simple, one-step chemical conversion treatment in chitosan to form a Mg (II)-chitosan complex layer. Mechanisms for the Mg-chitosan complexation process and for the coating bioactivity behavior in SBF were discussed. [ABSTRACT FROM AUTHOR]

Abstract Bambara groundnut is a protein-rich legume of African origin. This study investigated the influence of fractionation pH on degree of complexation of bambara protein isolate (BPI) with gum arabic (GA). BPI extracted at pH 2, pH 7, pH 9 and by the traditional salt solubilisation method were complexed with GA. BPI-GA complexes appeared as spherical particles (average size: 100–200 nm) that were aggregated. Optimal pHs of biopolymer interactions decreased (pH opt : 4.8 to 2.9) as protein extraction pH became more acidic. pH 2 fraction had the lowest coacervates yield (41%). ζ-potential profiles of protein fractions displayed similar pH dependent patterns, but with different pHs of net neutrality. The pH 2 fraction showed a high molecular weight protein (100 kDa), which was absent in other fractions. It also contained the highest content of basic amino acids. Protein extraction pH could be manipulated to produce better acid-stable structures on complexation with polysaccharides. Graphical abstract Image Highlights • Extraction pH significantly affected the degree of protein complexation with gum arabic. • Bambara protein –gum arabic coacervates appeared as spherical structures (100–200 nm). • High content of basic amino acids in protein fractions seems to lower coacervates yields. • PH opt of biopolymer interactions decreased as protein extraction pH become more acidic. [ABSTRACT FROM AUTHOR]

Abstract In order to investigate the immobilization ways of uranium (U(VI)) on Kocuria sp., we investigated the interaction behavior under different conditions by batch experiment. U(VI) products on Kocuria sp. were characterized by SEM, XRD, FTIR, and XPS techniques. SEM-EDS results presented U(VI) mineral-like precipitation formed on the cell surface which contained high percentage of P and U elements. XPS results also confirmed the appearance of bond P-O-U. XRD results illustrated characteristic UO 2 2+ peaks after U(VI) interaction with Kocuria sp. According to FTIR analysis, in addition to PO 4 3− groups, C O, OH, COOH groups might play important roles in complexation with U(VI). The biomineralization process of U(VI) on Kocuria sp. required longer time than sorption process, indicating that biomineralization was induced by the biosorption process. Our findings highlight the synergistic biosorption and biomineralization process of Kocuria sp. for U(VI) immobilization, which concentrated U(VI) on the cell surface via fast biosorption by providing nucleation sites for the precipitation to insoluble minerals, while the formation of U(VI) biomineral led to the relatively permanent immobilization of U(VI), and then emphasize the important roles of phosphate which are of significance in predicting the U(VI) immobilization properties. Graphical abstract Unlabelled Image Highlights • Effective U(VI) removal by Kocuria sp. • Fast biosorption provides nucleation sites for the precipitation to uranium biominerals. • PO 4 3− groups play an important role in biomineralization of U(VI). [ABSTRACT FROM AUTHOR]

A practical, two‐step synthesis of novel 4‐(substituted bis‐indolyl)methyl)benzo‐15‐crown‐5 has been reported. The strategy employed for the synthesis of the desired molecules involved Duff formylation of benzo‐15‐crown‐5 to get 4‐formyl benzo‐15‐crown‐5 followed by subsequent reactions with substituted indoles in trifluoroacetic acid to yield novel 4‐(substituted bis‐indolyl)methyl)benzo‐15‐crown‐5 in moderate to good yield. One of the reported novel molecule tested for the complexation behavior with various metal cations, such as Li+, Na+, K+, Mg2+ Ca2+, Al3+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Sn2+, Ba2+, Hg2+, and Pb2+, showed a visual colorimetric probe for the detection of mercury cations (Hg2+) in an aqueous medium. [ABSTRACT FROM AUTHOR]

Understanding the interaction of Pu(IV) with complexing agents present in the nuclear fuel cycle is important for predicting the performance of used nuclear fuel separations. The complexation of Pu(IV) with trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA) was studied in acidic solutions of 0.10-0.50 mol·L−1 HClO4 with 1.00 mol·L−1 (Na,H)ClO4 total ionic strength by a liquid-liquid extraction method using tracer quantities of 238Pu. The acid dissociation constants of CDTA and the autoprotolysis constant of water were determined via potentiometric titrations in 0.10-2.00 mol·L−1 NaClO4 and 25.0 ± 0.1 °C. The variation of the dissociation constants with ionic strength was modeled with the Specific ion Interaction Theory (SIT) and the associated SIT parameters were obtained. The thermodynamic dissociation constants at zero ionic strength for water and CDTA were determined from this analysis as pKwo = 14.00 ± 0.03, pKa2o = 1.52 ± 0.04, pKa3o  = 2.78 ± 0.05, pKa4o = 4.17 ± 0.04, pKa5o  = 6.75 ± 0.02, and pKa6o  = 10.64 ± 0.04 at 25.0 ± 0.1 °C. The results of the liquid-liquid extraction experiments indicated the formation of a 1:0:1 complex, PuCDTA0, and the presence of additional protonated species, Pu(HCDTA)+ and Pu(H2CDTA)2+, at these acidities. The corresponding stability constants in 1.00 mol·L−1 (Na,H)ClO4 and 23 ± 1 °C were determined to be log10 β101 = 24.2 ± 0.3, log10 β111 = 25.4 ± 0.2, and log10 β121 = 25.8 ± 0.1. [ABSTRACT FROM AUTHOR]

The simultaneous presence of heavy metals and surfactants in runoff induces complexation and ecological harm during migration. However, interactions between these pollutants are often overlooked in past studies. Thus, investigating heavy metal-surfactant complexes in runoff is imperative. In this work, Cu (II) and sodium dodecyl sulfate (SDS) were selected to investigate the interaction between heavy metals and surfactants due to the higher detected frequency in runoff. Through 1H NMR and FTIR observation of hydrogen atom nuclear displacement and functional group displacement of SDS, the change of SDS and Cu (II) complexation was obtained, and then the complexation form of Cu (II) and SDS was verified. The results showed that solution pH values and ionic strength had significant effects on the complexation of Cu (II). When the pH values increase from 3.0 to 6.0, the complexation efficiency of SDS with Cu (II) increased by 12.12% at low concentration of SDS, which may be attributed to the excessive protonation in the aqueous solution at acidic condition. The increase of ionic strength would inhibit the complexation reaction efficiency by 19.57% and finally reached the platform with concentration of NaNO 3 was 0.10 mmol/L, which was mainly due to the competitive relationship between Na (I) and Cu (II). As a general filtering material in stormwater treatment measures, natural zeolite could affect the interaction between SDS and Cu (II) greatly. After the addition of SDS, the content of free Cu (II) in the zeolite-SDS-Cu (II) three-phase mixed system was significantly reduced, indicating that SDS had a positive effect on the removal of Cu (II) from runoff. This study is of great significance for investigating the migration and transformation mechanism of SDS and Cu (II) in the future and studying the control technology of storm runoff pollution. [Display omitted] • The complexation characteristics of (SDS) and Cu (II) in runoff was investigated. • pH value and ionic strength showed influence on the complexation reaction between Cu (II) and SDS. • Natural zeolite could eliminate SDS-Cu (II) complex and improved removal efficiency of Cu (II). • The complexation mechanism and environmental implications were examined in stormwater runoff. [ABSTRACT FROM AUTHOR]

• Stable inclusion complexes are formed between gliclazide and β-cyclodextrin in aqueous solutions. • The inclusion process was spontaneous and enthalpy driven. • The complexes were stabilized by hydrogen bonds between CO—HO and SO—HO groups and van der Waals contacts. • Gliclazide-β-cyclodextrin complexes can be considered as potential carriers for targeted drug transport and delivery. Gliclazide (GLC) inclusion complexes with β-cyclodextrin (βCD) were studied by UV–VIS and FT-IR spectroscopy. The recorded spectra confirmed formation of GLC-βCD binary complexes and GLC-(βCD) 2 ternary complexes in aqueous solutions. UV–VIS measurements carried out for a number of temperatures allowed to determine the binding constants of the complexation reactions. The bioavailability of GLC-βCD and GLC-(βCD) 2 was determined using the n-octanol/water partition coefficient. Experimental studies were supplemented with theoretical calculations. Quantum-chemical calculations and classical molecular dynamics simulations were used to describe the interactions in the host-guest inclusion complexes. [Display omitted] [ABSTRACT FROM AUTHOR]