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PNAzymes are a group of artificial enzymes which show promising results in selective and efficient cleavage of RNA targets. In the present study, we introduce a series of metal chelating groups based on N,N-bis(2-picolyl) groups (parent, 6-methyl and 6-amino substituted) as the active sites of novel PNAzymes. An improved synthetic route for the 6-amino analogues is described. The catalytic activity of the chelating groups for cleaving phosphodiesters were assessed with the model substrate 2-hydroxypropyl p-nitrophenyl phosphate (HPNPP), confirming that the zinc complexes have the reactivity order of parent < 2-methyl < 2-amino. The three ligands were conjugated to a PNA oligomer to form three PNAzymes which showed the same order of reactivity and some sensitivity to the size of the RNA bulge designed into the catalyst–substrate complex. This work demonstrates that the kinetic activity observed for the model substrate HPNPP could be translated onto the PNAzymes, but that more reactive Zn complexes are required for such PNAzymes to be viable therapeutic agents. [ABSTRACT FROM AUTHOR]

Photochromic compounds are well known and attract tremendous necessity for their versatile applications in various fields of science. When exposed to light, metal complexes containing potentially photoswitchable azo (–N=N–) and imine (–C=N–) based ligands can be switched between trans (E) and cis (Z) two isomers, as well as energy manipulation and energy level modulation. Then the cis (Z) isomers underwent slow thermal isomerization back to the more stable trans (Z) isomers. The quantum efficiency of metal complexes has been tuned by modifying the ligands' structures and altering metal substrates. Herein our review encompasses the photochromic behavior of a few conjugated azo-imine (–N=N–C=N–), ligands such as arylazoimidazoles, phenylazopyridine, azobispyridine, arylazopyrozoles, as well as a few non-conjugated azo-imine or Schiff base ligands with their metal complexes. [ABSTRACT FROM AUTHOR]

Human serum albumin (HSA) efficiently transports drugs in vivo: most are organic. Therefore, it is important to delineate the binding of small molecules to HSA. Here, for the first time, we show that HSA binding depends not only on the identity of the d8 metal ion, NiII or PdII, of their complexes with bis(pyrrole-imine), H2PrPyrr, but on the pH level as well. Fluorescence quenching data for native and probe-bound HSA showed that sites close to Trp-214 (subdomain IIA) are targeted. The affinity constants, Ka, ranged from ~3.5 × 103 M−1 to ~1 × 106 M−1 at 37 °C, following the order Pd(PrPyrr) > Ni(PrPyrr) at pH levels of 4 and 7; but Ni(PrPyrr) > Pd(PrPyrr) at a pH level of 9. Ligand uptake is enthalpically driven, dependent mainly on London dispersion forces. The induced CD spectra for the protein-bound ligands could be simulated by hybrid QM:MM TD-DFT methods, allowing us to delineate the binding site of the ligands and to prove that the metal chelates neither decompose nor demetallate after uptake by HSA. The transport and delivery of the metal chelates by HSA in vivo is therefore feasible. [ABSTRACT FROM AUTHOR]

Abstract Human serum albumin (HSA) efficiently transports drugs in vivo: most are organic. Here, HSA binding affinity and site specificity are shown to depend on the identity of the d8 metal ion in NiII, PdII and PtII chelates of the bis(pyrrole‐imine) ligand H2PrPyrr. Fluorescence quenching data for native and probe‐bound HSA showed sites close to Trp‐214 (subdomain IIA) are targeted. The Stern‐Volmer constants, KSV, ranged from 104 M−1 to 105 M−1 while the affinity constants, Ka, ranged from ∼3.5×103 M−1 to ∼1×106 M−1 at 37 °C, following the order Pd(PrPyrr) > Pt(PrPyrr) > Ni(PrPyrr) > H2PrPyrr. Ligand uptake is enthalpically driven, hinging mainly on London dispersion forces. Induced CD spectra for the protein‐bound ligands could be simulated by hybrid QM:MM TD‐DFT methods, proving that the metal chelates neither decompose nor demetallate after uptake by HSA. Transport and delivery of the metal chelates by HSA in vivo could therefore be feasible.

Fluorine-19 magnetic resonance imaging (MRI) has gained considerable momentum as a promising imaging modality for in vivo tracking of cellular therapies and as a diagnostic for inflammatory disease. To further the utility of this technique, we increase imaging probe sensitivity by merging paramagnetic metal chelates with aqueous perfluorocarbon (PFC) nanoemulsions. We prepared a highly fluorinated ferric tris(β-diketonate) chelate (MW = 1265.2 g/mol) at gram scale. This iron chelate is soluble in multiple PFC oils used for MRI and readily reduces the 19F longitudinal relaxation time (T 1) to 200 days. Free β-diketonate or its iron complex in formed PFC nanoemulsion did not induce cytotoxicity in intracellularly labeled macrophages. Overall, ferric tris(β-diketonate) chelate provides a scalable approach for boosting sensitivity of PFC-based 19F MRI probes. More generally, it can functionalize PFC oil, whose chemical modification remains challenging.

Fluorine-19 MRI is an emerging cellular imaging approach, enabling lucid, quantitative "hot-spot" imaging with no background signal. The utility of 19F-MRI to detect inflammation and cell therapy products in vivo could be expanded by improving the intrinsic sensitivity of the probe by molecular design. We describe a metal chelate based on a salicylidene-tris(aminomethyl)ethane core, with solubility in perfluorocarbon (PFC) oils, and a potent accelerator of the 19F longitudinal relaxation time ( T1). Shortening T1 can increase the 19F image sensitivity per time and decrease the minimum number of detectable cells. We used the condensation between the tripodal ligand tris-1,1,1-(aminomethyl)ethane and salicylaldehyde to form the salicylidene-tris(aminomethyl)ethane chelating agent (SALTAME). We purified four isomers of SALTAME, elucidated structures using X-ray scattering and NMR, and identified a single isomer with high PFC solubility. Mn4+, Fe3+, Co3+, and Ga3+ cations formed stable and separable chelates with SALTAME, but only Fe3+ yielded superior T1 shortening with modest line broadening at 3 and 9.4 T. We mixed Fe3+ chelate with perfluorooctyl bromide (PFOB) to formulate a stable paramagnetic nanoemulsion imaging probe and assessed its biocompatibility in macrophages in vitro using proliferation, cytotoxicity, and phenotypic cell assays. Signal-to-noise modeling of paramagnetic PFOB shows that sensitivity enhancement of nearly 4-fold is feasible at clinical magnetic field strengths using a 19F spin-density-weighted gradient-echo pulse sequence. We demonstrate the utility of this paramagnetic nanoemulsion as an in vivo MRI probe for detecting inflammation macrophages in mice. Overall, these paramagnetic PFC compounds represent a platform for the development of sensitive 19F probes.

The possibility of formation of heteroligand (6,6,6,6)-macrotetracyclic chelate complexes of 3d-elements (M = Cr, Mn, Fe) with trans-dibenzoporphyrazine as the (N,N,N,N)-donor ligand and two O2− anions was studied in terms of the density functional theory. The OPBE/TZVP method predicts complexation only in the systems with M = Cr, Fe. According to B3PW91/TZVP calculations, all the 3d-elements studied can form complexes with the structure of a slightly distorted octahedron and planar chelate site MN4. All six-membered metal chelate rings in the complexes are identical to one another. The key bond lengths, bond angles, and non-bond angles in the complexes were determined and the corresponding standard enthalpies, entropies, and Gibbs energies of formation were calculated. [ABSTRACT FROM AUTHOR]

The antimicrobial properties of 8-Hydroxyquinoline (8-Hq), a small organic compound known for its metal-chelating capabilities, hold significant promise. However, its limited solubility in water poses a challenge for practical applications. In this study, we address this limitation by augmenting the antimicrobial efficacy of 8-Hq through its integration into the metal-organic framework UiO-66 (named 8-Hq@UiO-66) and coupling it with iron ions (designated as Fe/8-Hq@UiO-66) via an adsorption process. The sorption isotherm and adsorption kinetics were meticulously examined using Langmuir's adsorption model and the pseudo-second-order kinetic model. Material characterization techniques including powder X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption isotherms, ultraviolet–visible spectroscopy, and photoluminescence spectroscopy revealed the coordination of zirconium clusters and iron with the nitrogen and hydroxyl groups of 8-Hq, respectively. Furthermore, our investigation into metal ion adsorption demonstrated that the 8-Hq@UiO-66 composite displayed a notable selectivity for iron ions over other metal ions in aqueous media. Under optimized conditions, the adsorption capacity for iron ions ranged from approximately 34–46 mg g−1. Importantly, the Fe/8-Hq@UiO-66 composite exhibited potent antimicrobial activity against Bacillus subtilis , Staphylococcus aureus , and Escherichia coli. These findings underscore the potential of incorporating 8-Hq into porous metal-organic frameworks and coupling it with iron ions to enhance its antimicrobial efficacy. [Display omitted] • Enhanced antimicrobial efficacy via 8-Hq and iron ion integration into UiO-66. • Insights from sorption isotherms and kinetics models. • Selective conjugation of iron ions by 8-Hq@UiO-66. • Potent antimicrobial activity against diverse bacterial strains demonstrated. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop a stable immobilized enzyme biocatalyst for the isomerization of d‐galactose to d‐tagatose at high temperature. l‐Arabinose isomerase from the hyperthermophilic bacterium Thermotoga maritima (TMAI) was produced as a (His)6‐tagged protein, immobilized on a copper–chelate epoxy support and subjected to several postimmobilization treatments aimed at increasing its operational and structural stability. Treatment with glutaraldehyde and ethylenediamine resulted in a more than twofold increase in the operational stability and in all enzyme subunits linked, directly or indirectly, to the support via covalent bonds. A postimmobilization treatment of the immobilized derivatives with mercaptoethanol for the removal of any remaining copper ions, determined a further increase of the operational biocatalytic activity. Immobilized derivatives subjected to both treatments were used for the bioconversion of 18 g/L d‐galactose to d‐tagatose at 80°C in a packed bed reactor in three repeated cycles and showed a better operational stability compared with the literature data. This study shows that a postimmobilization stabilization treatment with glutaraldehyde and ethylenediamine can stabilize the multi‐subunit structure of an enzyme immobilized on a metal‐chelate epoxy support with an increase of its operational stability, results that are not easily achievable with the sole immobilization on epoxy or metal chelate‐epoxy supports in the case of complex multimeric enzymes with geometric incongruence with the support. [ABSTRACT FROM AUTHOR]

The molecular structures of (6666) macrotetracyclic (M(IV) chelates (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu) with the (NNNN)-donor ligand porphyrazine and the oxo ligand have been calculated by the DFT OPBE/TZVP method. Selected bond lengths and bond and nonbonded angles in the complexes have been reported. The standard enthalpies, entropies, and Gibbs energies of formation of these compounds have been calculated. All these complexes have a structure of a distorted tetragonal pyramid, where the complex-forming M(IV) atom is located above the base formed by the donor nitrogen atoms. It has been demonstrated that all six-membered metal chelate rings in each of these structures are identical to each other both in the sum of their bond angles and in their set, although none of them is flat. The images of the molecular structures of some of these coordination compounds are presented. [ABSTRACT FROM AUTHOR]

The molecular structures of heteroligand (6666)macrotetracyclic chelates of M(III) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, or Cu) with porphyrazine (an (NNNN)-donating ligand) and F– ion are calculated by the DFT OPBE/TZVP method. The key bond lengths, bond angles, and nonbonded angles in these complexes are reported. The standard enthalpies, entropies, and Gibbs free energies of formation are calculated for the complexes. All complexes have a slightly distorted tetragonal-pyramidal geometry, where the complex former M(III) is to some degree raised above the pyramid base made up of the donor nitrogen atoms. Characteristically, all 6-membered metal chelate rings in these metal chelates are identical to one another both in terms of the sum of bond angles and in their varieties. [ABSTRACT FROM AUTHOR]

Molecular structure calculations of heteroligand (6666)macrotetracyclic metal (MIV) chelates (M = Fe, Co, Ni, Cu) with trans-di[benzo]porphyrazine as the (N,N,N,N)-donor ligand and two F− anions were carried out at the OPBE/TZVP level of density functional theory. The key bond lengths, bond angles, and non-bond angles in the complexes were determined and corresponding standard enthalpies, entropies, and Gibbs energies of formation were calculated. All complexes have slightly distorted tetrahedral structures. The complex-forming agent MIV lies in the plane formed by the donor nitrogen atoms. The metal—nitrogen bonds are usually pair-wise equal. The six-membered metal chelate rings in the complexes are identical to one another from the standpoint of both the sum and set of the bond angles. [ABSTRACT FROM AUTHOR]

New complex (1) based on nickel(II) maleate and 4′-phenyl-2,2′:6′,2″-terpyridine (L) was synthesized. The complex 1 is a 1D coordination polymer formed from a L-Ni(II) node bridged by maleate ligands and crystallizes in monoclinic form with space group P21/n. There are two Ni(II) moiety's in the asymmetric unit. Each nickel atom is five coordination and is chelated by three nitrogen atoms of L and two oxygen atoms of Mal fragments with the formation of a NiN3O2 chelate node. The polyhedron of the first Ni(II) moiety is close to the ideal tetragonal pyramidal structure, while the polyhedron of the second Ni(II) moiety belongs to the distorted tetragonal pyramidal structure. The main stages and kinetics features of the conjugated thermolysis of complex 1 were evaluated. Metal–polymer nanocomposite containing Ni nanoparticles uniformly distributed in a stabilizing nitrogen-containing polymer matrix was obtained. [ABSTRACT FROM AUTHOR]

This article discusses the development of cold curing adhesives based on nitrile butadiene rubbers (NBRs) containing chlorinated polymers and metal chelates as enhancers and the strengthening mechanism of adhesive joints upon application of such components. The influence of the solvent nature on the adhesive strength of adhesive joints has been analyzed using thermodynamic approach, the reasonability of application of ethyl acetate has been demonstrated. A synergistic effect on adhesive properties of adhesives and their stability has been detected upon combined use of copper chelate and chlorinated natural rubber in adhesives based on nitrile butadiene rubbers. Optimum ratios in the polymer base of adhesives based on NBR/chlorinated natural rubber and concentration of copper chelate have been determined that improve the adhesive strength between rubber substrates by 2–2.5 times in comparison with adhesives based on NBRs. [ABSTRACT FROM AUTHOR]

The analysis of the use of chalcogenide metal chelates as single-source precursors of nanostructured materials has been carried out. The influence of the nature of the ligand, temperature, capping agents, thermolysis time, and solvent on the kinetic laws of thermolysis and the properties of the resulting nanomaterials is considered. Particular attention is paid to thermolysis of polynuclear chalcogenide metal chelates. The basic data on the synthesis of metal-polymer nanocomposites by thermolysis of chalcogenide metal chelates in the presence of polymers are summarized. The problems and future prospects of obtaining nanostructured materials by thermolysis of chalcogenide metal chelates are outlined. The bibliography includes articles published during the last 5 years. [ABSTRACT FROM AUTHOR]

The data about of soft template synthesis proceeding in gelatin matrices in [3d-element M(II) ion – (N,S)- or (N,O,S)-ambidentate ligson – mono- or dicarbonyl ligson] systems, have been considered and discussed. The chemical nature of the final products of template synthesis formed under these specific conditions, has been compared with the chemical nature of the final products formed by template synthesis in solutions. It has been noted that in many cases, the nature and chemical composition of these products differ substantially. Specific features of the DFT calculated molecular structures of the macrocyclic compounds that can be formed due to the template synthesis in the systems indicated above, have been discussed, too. The review covers the period 1990–2015.

Abstract Synthesis and structural characterization of three new isomorphous coordination compounds, fabricated from CdHal 2 (Hal = Cl, Br, I) and a bulky helical organic ligand 1,2-diphenyl-1,2-bis((phenyl(pyridin-2-yl)methylene)hydrazono)ethane (L), namely [CdHal 2 L] (Hal = Cl (1), Br (2), I (3)), are reported. The ligand L is coordinated in a tetradentate coordination mode via two pyridyl-imine units, yielding the 12 π electron chelate ring. Herein, we indicated that using the pyridine based bulky ligand along with CdHal 2 salts led to formation of desirable helical metallo-organic molecules with octahedral geometry. It was found that all the structures exhibit intermolecular π⋯π stacking and C H⋯π interactions. The Hirshfeld analysis indicated that the H⋯X (X = H, C and Hal) contacts are highly favoured in 1 – 3. The optical properties of 1 – 3 have been investigated by diffuse reflectance spectroscopy. Graphical abstract Three new coordination compounds fabricated from CdHal 2 (Hal = Cl, Br, I) and a helical organic ligand 1,2-diphenyl-1,2-bis((phenyl(pyridin-2-yl)methylene)hydrazono)ethane (L) in MeOH, namely [CdCl 2 L] (1), [CdBr 2 L] (2) and [CdI 2 L] (3). Hirshfeld surface analysis showed that the structures of 1 – 3 are highly dominated by H⋯X (X = H, C and Hal) contacts. In the diffuse reflectance spectra, 1 – 3 each exhibit bands up to about 500 nm. Image Highlights • Coordination compounds of Cd(II) and 1,2-diphenyl-1,2-bis((phenyl(pyridin-2-yl)methylene)hydrazono)ethane were synthesized. • Hirshfeld surface analysis exhibited highly dominated H⋯X (X = H, C and Hal) contacts in the structures. • The optical properties have been investigated by diffuse reflectance spectroscopy. [ABSTRACT FROM AUTHOR]

Polyamines such as triethylenetetramine (TETA) and other amine chelators are used in mineral processing applications. Formation of heavy metal complexes of these reagents as a by-product in effluent water is a recent environmental concern. In this study, Paecilomyces sp. was enriched from soil on TETA as the sole source of carbon and nitrogen and was found to degrade > 96 and 90% CuTETA complexes at initial concentrations of 0.32 and 0.79 mM respectively, following 96-h incubation. After destabilization, most of the copper (> 78%) was complexed extracellularly and the rest was associated with the cell. Mass spectroscopy results provided confirmation that copper re-complexed with small, extracellular, and organic molecules. There are no reports in the literature that Paecilomyces or any other organism can grow on TETA or CuTETA. This study is the first to show that biological destabilization of CuTETA complexes in mineral processing effluents is feasible. [ABSTRACT FROM AUTHOR]

• A new azo-azomethine and its metal complexes were prepared and characterized. • The solid state structure of the azo-azomethine ligand was determined by XRD. • Theoretical calculations of possible isomers of the ligand and complexes were studied. • Electrochemical and photoluminescence properties of the compounds were investigated. A new bidentate azo-azomethine ligand 2-{(E)-[(3,4- dimethylphenyl) imino ]methyl}-4-[(E)-(4- ethylphenyl) diazenyl ]phenol (2) and its copper(II) and zinc(II) complexes (3) and (4) were synthesized and characterized by elemental analysis, 1H/13C NMR (for the ligand 2 and its Zn(II) complex) and IR spectral measurements. The structure of the ligand 2 was also determined by single crystal X-ray diffraction. The structure was solved in monoclinic unit cell and P2 1 /n space group with final R value of 0.0586. In the structure of the ligand, the imine (CH N) bond distance is of 1.276(2) Å which confirms the phenol-imine tautmeric form in the crystalline state. In the structure, molecules are stacked by π-π (edge to edge) interactions. The electrochemical and photoluminescence properties of the synthesized azo-azomethine ligand and its metal complexes were investigated. Also, computational studies of related compounds were performed by using M062X/6-31+G level in vacuum. The potential VEGFR2 inhibitory properties of the synthesized ligand and its possible tautomers was investigated by the docking study. As for the ligand structures, azo-imine form is so reactive against the VEGFR2 protein and its docking score and total interaction energy are better than those of other tautomers. [Display omitted] [ABSTRACT FROM AUTHOR]

SnS 2 material is considered as a promising anode material for Na-ion batteries (NIBs) because of its unique layered structure and high theoretical capacity. However, SnS 2 nanosheets are easily overlapped during synthesis and cycling process. Also, they have to experience large volume change during repeated sodiation-desodiation processes. A promising concept is the application of hierarchical hollow structures for improving electrode stability upon cycling. However, they usually rely on template methods that require complex procedures such as chemical etching or calcination to remove inner template. Here, we demonstrate a simple and innovative strategy for fabricating the SnS 2 nanosheets assembled hierarchical tubular structures (SnS 2 NS ⊂ HTSs) by using cobalt-nitrilotriacetic acid chelate nanowires as soluble template, which makes shell growth and core template dissolution occur simultaneously in one step reaction. Owing to the hollow interior and well separated nanosheets with maximally exposed edges, the SnS 2 NS ⊂ HTSs exhibit excellent electrochemical performance. When evaluated as the anode material for NIBs, it delivers a high discharge capacity of 708 mAh g −1 at 50 mA g −1 and still remains up to 414 mAh g −1 after 50 cycles. [ABSTRACT FROM AUTHOR]

The work describes in detail the structure of a coordination platinum(II) compound with the sulfur-and nitrogen-containing biologically active β-mercaptoethylamine ligand NH2CH2CH2SH which deprotonates during synthesis and acts simultaneously as a chelating and bridging ligand resulting in the formation of the hexanuclear [Pt6(NH2CH2CH2S)8]Cl4·3H2O complex of a non-cluster type. Depending on the conditions, in particular, medium pH, complexes with different nuclearities and hydration numbers can form in this system. [ABSTRACT FROM AUTHOR]

Genistein, but not daidzein, binds to copper(II) with a 1:2 stoichiometry in ethanol and with a 1:1 stoichiometry in methanol, indicating chelation by the 5-phenol and the 4-keto group of the isoflavonoid as demonstrated by the Jobs method and UV-visible absorption spectroscopy. In ethanol, the stability constants had the value 1.12 × 1011 L²·mol-2 for the 1:2 complex and in methanol 6.0 × 105 L·mol-1 for the 1:1 complex at 25 °C. Binding was not detected in water, as confirmed by an upper limit for the 1:1 stability constant of K = 5 mol-1 L as calculated from the difference in solvation free energy of copper(II) between methanol and the more polar water. Solvent molecules compete with genistein as demonstrated in methanol where binding stoichiometry changes from 1:2 to 1:1 compared to ethanol and methanol/chloroform (7/3, v/v). Genistein binding to copper(II) increases the scavenging rate of the stable, neutral 2,2-diphenyl-1-picrylhydrazyl radical by more than a factor of four, while only small effects were seen for the short-lived but more oxidizing β-carotene radical cation using laser flash photolysis. The increased efficiency of coordinated genistein is concluded to depend on kinetic rather than on thermodynamic factors, as confirmed by the small change in reduction potential of -0.016 V detected by cyclic voltammetry upon binding of genistein to copper(II) in methanol/chloroform solutions. [ABSTRACT FROM AUTHOR]

In this study, a supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based Cu 2 + -attached bentonite particles embedded hybrid monolithic cryogel (Cu 2 + -ABPs EHMC) was prepared by radical cryo-copolymerization of HEMA with N,N ′-methylene-bis-acrylamide (MBAAm) as a cross-linker directly in a plastic syringe in the presence of Cu 2 + -ABPs, and used for hemoglobin (Hb) separation from aqueous solution. Due to the naturally abundant hydroxyl groups on bentonite, Cu 2 -attached bentonite particles (Cu 2 + -ABPs) embedded hybrid monolithic cryogel (HMC) showed a good adsorption performance for Hb, covering an excellent adsorption capacity of 521.6 mg/g bentonite in phosphate buffer at pH 6.0 with a flow rate of 0.5 mL/min, fast binding stability within 60 min, well selectivity and reversibility. Compared with other adsorbent systems used for protein separation, this sorbent has many advantages such as excellent adsorption performance, ease of preparation, suitable, effective and environment-friendly to perform, which can serve as a more sustainable material in protein separation and purification. [ABSTRACT FROM AUTHOR]

Supercritical fluid extraction (SFE), as a new green extraction technology, has been used in extracting various metal species. The solubilities of chelating agents and corresponding metal chelates are the key factors which influence the efficiency of SFE. Other main properties of them such as stability and selectivity are also reviewed. The extraction mechanisms of mainly used chelating agents are explained by typical examples in this paper. This is the important aspect of SFE of metal ions. Moreover, the extraction efficiencies of metal species also depend on other factors such as temperature, pressure, extraction time and matrix effect. The two main complexation methods namely in-situ and on-line chelating SFE are described in detail. As an efficient chelating agent, tributyl phosphate-nitric acid (TBP-HNO3) complex attracts much attention. The SFE of metal ions, lanthanides and actinides as well as organometallic compounds are also summarized. With the proper selection of ligands, high efficient extraction of metal species can be obtained. As an efficient sample analysis method, supercritical fluid chromatography (SFC) is introduced in this paper. Recently, the extraction method combining ionic liquids (ILs) with supercritical fluid has been becoming a novel technology for treating metal ions. The kinetics related to SFE of metal species is discussed with some specific examples. [ABSTRACT FROM AUTHOR]

In this study, chromatographic performance of Cu2+-attached pumice particles embedded to monolithic cryogels (Cu2+-APPsEMC) for human serum albumin (HSA) was investigated. Monolithic composite cryogels were prepared by means of polymerization of gel-forming precursors at sub-zero temperatures. The chemical composition of pumice and surface of composite cryogels were determined by X-ray fluorescence spectrometer and scanning electron microscopy, respectively. The highest adsorption capacity (549.5 mg/g pumice) of cryogels was achieved at phosphate buffer of pH 8.0 with initial HSA solution of 3 mg/ml. SDS-PAGE analysis was performed for the samples studied on human serum to determine HSA adsorption/desorption performance of cryogel qualitatively. [ABSTRACT FROM AUTHOR]

The data about of soft template synthesis proceeding in gelatin matrices in [3 d -element M(II) ion – (N,S)- or (N,O,S)-ambidentate ligson – mono- or dicarbonyl ligson] systems, have been considered and discussed. The chemical nature of the final products of template synthesis formed under these specific conditions, has been compared with the chemical nature of the final products formed by template synthesis in solutions. It has been noted that in many cases, the nature and chemical composition of these products differ substantially. Specific features of the DFT calculated molecular structures of the macrocyclic compounds that can be formed due to the template synthesis in the systems indicated above, have been discussed, too. The review covers the period 1990–2015. [ABSTRACT FROM AUTHOR]

Six dual functional ionic liquids (DFILs) with metal chelate cation and pyrazolide anion were synthesized by reacting alkanolamine with pyrazole sodium salt, and characterized by 1 H NMR, 13 C NMR, FT-IR, and ESI–MS spectra. Thermal decomposition temperature and viscosity were determined. The behavior of CO 2 absorption for these DFILs was evaluated at T = 353.2 K. Absorption mechanism and the influence of temperature and N 2 on the CO 2 absorption were investigated. The results show that the CO 2 capacity of the DFILs consisting of alkanolamine with pyrazole sodium in a molar ratio of 2:1 is larger than that of the DFILs in a molar ratio of 1:1. The CO 2 absorption mechanism obtained from FT-IR and 13 C NMR spectra indicates that CO 2 could react with a quasi-aza-crown ether cation and pyrazolide anion simultaneously, resulting in improved capacity of CO 2 absorption. According to the saturated CO 2 absorption capacity at 333.2–363.2 K and van’t Hoff’s equation, the enthalpy of CO 2 absorption for three DFILs is derived. Furthermore, the DFILs were carried out for five cycles with no obvious loss in the absorption capacity of CO 2 , indicating that these DFILs may be good candidates for efficient CO 2 capture at relatively high temperature. [ABSTRACT FROM AUTHOR]

A quinone methide precursor featuring a bis-cyclen anchoring moiety has been synthesized and its capacity to alkylate oligonucleotide targets quantified in the presence and absence of divalent metal ions (Zn2+, Ni2+ and Cd2+). The oligonucleotides were designed for testing the sequence and secondary structure specificity of the reaction. Gel electrophoretic analysis revealed predominant alkylation of C-rich bulges, regardless of the presence of divalent metal ions or even the bis-cyclen anchor. This C-selectivity appears to be an intrinsic property of the quinone methide electrophile as reflected by its reaction with an equimolar mixture of the 2′-deoxynucleosides. Only dA-N1 and dC-N3 alkylation products were detected initially and only the dC adduct persisted for detection under conditions of the gel electrophoretic analysis. [ABSTRACT FROM AUTHOR]

Zinc N -morpholinomethylphosphonic acid (MMPA-Zn) is synthesized by hydrothermal reactions used zinc acetate and N -morpholinomethylphosphonic acid as raw materials. TGA shows that the TG onset temperature of decomposition of MMPA-Zn is 391 °C and the final residue at 700 °C is 65.3 wt%, indicating its good thermal stability and char-forming ability. Then, MMPA-Zn is used as flame retardant in high density polyethylene (HDPE). The thermal property and flame retardancy of various HDPE compositions were investigated by TGA and cone calorimeter (Cone). TG data show that MMPA-Zn can improve the thermal stability and char residue yield, which is dependent on the loading amount of MMPA-Zn. The Cone data indicate that the PHRR and the emission of CO decreased obviously because of the joint effect of Zn and the MMPA in MMPA-Zn molecular, which can yield more char residue in the HDPE/MMPA-Zn system. [ABSTRACT FROM AUTHOR]

Highlights: [•] An integrative method of protein refolding and metal-chelate capture was proposed. [•] Iminodiacetic acid modified resins facilitate refolding of like-charged His-tagged protein. [•] Addition of nickel ions leads to the affinity capture of the His-tagged protein. [•] Facilitated refolding and purification of the His-tagged protein are realized. [ABSTRACT FROM AUTHOR]

Abstract: For the purification of large molecules, cryogels are an alternative stationary phase to particle based media. But, due to the drawbacks of cryogels (i.e., low surface area) and particle sorbents (i.e., pressure drop in fixed beds), in recent years, the use of hybrid cryogels has greatly increased. In this study, a novel hybrid cryogel column was synthesized for the purification of lysozyme from aqueous solutions and hen egg white (HEW). Firstly, poly(2-hydroxyethyl methacrylate) beads (2μm size) were prepared, and after iminodiacetic acid (IDA) immobilization, Cu2+ ions were attached via the IDA chelating groups. These arranged Cu2+-attached PHEMA beads (Cu2+-ABs) were located into PHEMA based cryogel in order to prepare Cu2+-ABs embedded supermacroporous hybrid cryogel (Cu2+-ABsEHC) column. The specific surface area of the hybrid cryogel was found as 95m2/g by using BET. The amount of IDA on beads was found as 875μmol IDA/g. It was approached to the optimum adsorption levels at initial lysozyme concentration of 4mg/mL and pH8.0 as 874.9mg/g beads. The purity of lysozyme adsorbed from HEW was studied by SDS-PAGE with a purity of 86.4%. It is demonstrated that this column is a potential separation medium for purification of lysozyme from HEW. [Copyright &y& Elsevier]

Phosphate anions play important part in the specific donor-acceptor interactions with humic acids, leading to the changes of structure and properties of the latter. Formation of the chelate nodes containing aluminum and iron atoms in the humic acids structure upon overphosphating has been observed. Behavior of Pmodified humic acids in the polar media has been discussed. [ABSTRACT FROM AUTHOR]