Isolation of single crystals of homoleptic UO22+- diglycolamide complex from a room temperature ionic liquid: X-ray crystallography and complexation studies

Complexation and structural investigations of the solid complex of UO22+ ion and N,N,N’,N’-tetramethyl diglycolamide isolated from a room temperature ionic liquid, for the first time, revealed that the nature and...

Polymeric Terbium(III) Squarate Hydrate as a Luminescent Magnet

Polymeric terbium(III) squarate hydrate [{Tb2(C4O4)3(H2O)8}n] was prepared from TbCl3 or Tb2O3 and squaric acid. The crystal structure was determined in a monoclinic Pc space group, and the whole molecular arrangement gives a sandwiched two-dimensional structure. The coordination polyhedra are described as a square antiprism. The solid complex emits green light under UV irradiation at room temperature with the quantum yield of 25%. Although Tb3+ is a non-Kramers ion, the alternating-current magnetic susceptibility showed frequency dependence in a 2000-Oe DC field, and the effective energy barrier for magnetization reorientation was 33(2) K. Thus, [{Tb2(C4O4)3(H2O)8}n] displayed functions of a potential luminescent magnet.

SYNTHESIS AND PROPERTIES OF NEW NANOSYSTEMS OF ARGENTUM

AgEDTA complexonate was synthesized, the manner of coordination of the Argentum (I) ion to the functional groups of complexone was determined. It was found that the solid complex precipitates from the solution in the form of a fine powder. It is shown that the size and shape of nanoparticles of Argentum complexonate depend on the solvent-precipitator. A stable dispersed system based on the synthesized complexonate was obtained. The shape and position of the surface plasmon resonance bands confirm the presence of spherical nanoparticles with a size of 15–30 nm in both dispersed systems. Investigations of the biological activity of the powder of AgEDTA has shown that it has a high bactericidal effect against gram-positive bacteria.

Features of adsorption processes for wastewater treatment from zinc ions

The results of adsorption properties of complex natural sorbents in relation to the neutralization of zinc ions from wastewater are presented. The adsorption isotherm of Zn2+ ions on complex sorbents (clinoptilolite-shungite) (1:1) according to Langmuir and Freundlich models is constructed, the type of adsorption isotherms according to S. Brunauer classification is established. The value of the maximum sorption capacity of Gmax complex sorbents for Zn2+ ions is calculated. The peculiarities of the sorption process of zinc ions with the formation of a monomolecular layer based on the calculated coefficients of the Langmuir and Freundlich were found. The optimal conditions for the dependence of the degree of absorption of Zn2+ ions by complex sorbents on the duration of the sorption process are determined. The ratio "solid (complex sorbent) - liquid" was determined experimentally.

Electrochemical formation and dissolution of an Iodine-Halide coordination solid complex in a nano-confined space

Iodide and iodine comprise a promising redox couple in aqueous energy storage systems (aqua-ESSs). However, the corresponding half-redox reaction on the cathode of an aqua-ESS has most often been considered...

Preparation and Properties of (1-Hydroxyethylidene) Diphosphonic Acid Aminium Salts

An overview of the preparation methods and properties of (1-hydroxyethylidene) diphosphonic acid aminium salts is presented. (1-Hydroxyethylidene) diphosphonic acid with monoethanolamine forms a crystalline compound, which, according to the elemental analysis and XRD data, is ternary C(CH3)(OH)[P(O)O-NH3+CH2CH2OH]3[P(O)(OH)] amine salt. A characteristic feature of the derivatives of (1-hydroxyethylidene) diphosphonic acid and tris (hydroxymethyl)aminomethane is the formation of glassy and resinous products. Their composition Н4L∙4NH2C(CH2OH)3 corresponds to 4 base molecules per 1 tetrabasic acid molecule. The addition of 4 molecules of the primary amine occurs both when the ratio of the initial reagents is 1: 4 and 1: 3. The polymer structure and the presence of strong hydrogen bonds in the Н4L∙4NH2C(CH2OH)3 compound lead to its very low solubility in organic media and good solubility in water. The solubility of Н4L∙4NH2C(CH2OH)3 in methanol is 1.8 g per 100 mL. The reaction of (1-hydroxyethylidene)diphosphonic acid with para-aminobenzoic acid leads to the formation of bis(4-carboxyphenylamine)(1-hydroxyethylidene)diphosphonate C(CH3)(OH)[P(O)(OH)O-NH3+C6H4С(О)ОН]2. In a crystal, this compound consists of the anion of the double-deprotonated (1-hydroxyethylidene)diphosphonic acid C(CH3)(OH)[P(OH)(O)O-]2 and two amine cations NH3+C6H4С(О)ОН. The tetrabasic acid binds 3 molecules of morpholine, giving tris(morpholinium)(1-hydroxyethylidene)diphosphonate H4L•3HN(CH2CH2)2O in the form of a white powder that dissolves well in water, methyl and ethyl alcohols. The solid complex of morpholine with (1-hydroxyethylidene)diphosphonic acid does not crystallize from various solvents, which may be caused by the oligomeric form of morpholine included in the molecule of the complex with H4L.

Synthesis and Visualization of a Novel Fluorescent-Tagged Polymeric Antiscalant during Gypsum Crystallization in Combination with Bisphosphonate Fluorophore

An attempt to reveal the mechanisms of scale inhibition with the use of two different fluorescent-tagged antiscalants at once is undertaken. To reach the goal, a novel 1,8-naphthalimide-tagged polyacrylate (PAA-F2) is synthesized and tested separately and jointly with 1,8-naphthalimide-tagged bisphosphonate (HEDP-F) as a gypsum scale inhibitor within the frames of NACE Standard TM0374-2007. Here, it is found that at a dosage of 10 mg·dm−3 it provides a much higher inhibition efficiency (96%) than HEDP-F (32%). A PAA-F2 and HEDP-F blend (1:1 mass) has an intermediate efficacy (66%) and exhibits no synergism relative to its individual components. The visualization of PAA-F2 revealed a paradoxical effect: an antiscalant causes modification of the CaSO4·2H2O crystals habit, but does not interact with them, forming particles of its own solid complex [Ca-PAA-F2]. This paradox is interpreted in terms of the “nano/microdust” concept, prioritizing the bulk heterogeneous nucleation step, while an ability of the scale inhibitor to block the nucleus growth at the next steps is proven to be of secondary importance. At the same time, HEDP-F does not change the gypsum crystals morphology, although this antiscalant is completely located on the surface of the scale phase. The PAA-F2 and HEDP-F blend revealed an accumulation of both antiscalants in their own [Ca-PAA-F2/Ca-HEDP-F] phase with some traces of HEDP-F and PAA-F2 on the CaSO4·2H2O crystals surface. Thus, the visualization of two different antiscalants separately and jointly applied to gypsum deposition demonstrates differences in phosphonic and polymeric inhibitors location, and a lack of causal relationship between antiscalant efficiency and scale particle habit modification. Finally, it is shown that the confocal microscopy of several fluorescent antiscalant blends is capable of providing unique information on their interrelationships during scale deposition.

Identification of methionine -rich insoluble proteins in the shell of the pearl oyster, Pinctada fucata

The molluscan shell is a biomineral that comprises calcium carbonate and organic matrices controlling the crystal growth of calcium carbonate. The main components of organic matrices are insoluble chitin and proteins. Various kinds of proteins have been identified by solubilizing them with reagents, such as acid or detergent. However, insoluble proteins remained due to the formation of a solid complex with chitin. Herein, we identified these proteins from the nacreous layer, prismatic layer, and hinge ligament of Pinctada fucata using mercaptoethanol and trypsin. Most identified proteins contained a methionine-rich region in common. We focused on one of these proteins, NU-5, to examine the function in shell formation. Gene expression analysis of NU-5 showed that NU-5 was highly expressed in the mantle, and a knockdown of NU-5 prevented the formation of aragonite tablets in the nacre, which suggested that NU-5 was required for nacre formation. Dynamic light scattering and circular dichroism revealed that recombinant NU-5 had aggregation activity and changed its secondary structure in the presence of calcium ions. These findings suggest that insoluble proteins containing methionine-rich regions may be important for scaffold formation, which is an initial stage of biomineral formation.

STUDY OF THERMAL CHARACTERISTICS OF THE EUROPIUM (III) COMPLEX WITH HIGH-MOLECULAR HEPARIN

Синтезировано твердое комплексное соединение высокомолекулярного гепарина с европием (III) ([EuHep]•3HO). Проведен синхронный термический анализ [EuHep]•3HO. Определены термическая устойчивость, температура дегидратации и количество кристаллизационной воды, количество металла в комплексе. Описаны наиболее значимые стадии термодеструкции и на основе данных ИК-спектроскопии предположены образующиеся продукты. A solid complex compound of high molecular weight heparin with europium (III) was synthesized. A synchronous thermal analysis of [EuHep]•3HO was performed. Thermal stability, dehydration temperature and the amount of crystallization water, the amount of metal in the complex are determined. The most significant stages of thermal degradation are described and, based on the data of IR spectroscopy, the products formed are assumed.