Solutions Of Complexes Research Articles

Electronic Structure of Neodymium(III) and Europium(III) Resolved in Solution Using High-Resolution Optical Spectroscopy and Population Analysis.

Solution chemistry of the lanthanide(III) ions is unexplored and relevant: extraction and recycling processes exclusively operate in solution, MRI is a solution-phase method, and bioassays are done in solution. However, the molecular structure of the lanthanide(III) ions in solution is poorly described, especially for the near-IR (NIR)-emitting lanthanides, as these are difficult to investigate using optical tools, which has limited the availability of experimental data. Here we report a custom-built spectrometer dedicated to investigation of lanthanide(III) luminescence in the NIR region. Absorption, luminescence excitation, and luminescence spectra of five complexes of europium(III) and neodymium(III) were acquired. The obtained spectra display high spectral resolution and high signal-to-noise ratios. Using the high-quality data, a method for determining the electronic structure for the thermal ground states and emitting states is proposed. It combines Boltzmann distributions with population analysis and uses the experimentally determined relative transition probabilities from both excitation and emission data. The method was tested on the five europium(III) complexes and was used to resolve the electronic structures of the ground state and the emitting state of neodymium(III) in five different solution complexes. This is the first step toward correlating optical spectra with chemical structure in solution for NIR-emitting lanthanide complexes.

The Place and Role of Hydraulic Coupling in the Heating System

The purpose of the work is to consider the issues of optimal load on the heating system with the use of hydraulic balancing of the system, installation of a balancing valve. The tasks of applying energy-saving measures are disclosed. The main measures and engineering solutions that provide the specified conditions in the premises of the building are described. The approach to the study of the energy indicators of the system with the use of additional fittings and the search for the right solutions to optimize their energy efficiency, the determination of the solution of complex interrelated tasks, which constitute three main directions, is considered: - organization of indoor microclimate; - minimization of energy costs; - rational use of material resources.

ISOLATION, STRUCTURE AND PHYSICO-CHEMICAL PROPERTIES OF CHITIN-GLUCAN COMPLEXES OF HIGHER FUNGI

The article is devoted to the study of isolation processes, chemical structure and rheological properties of chitin-glucan complexes from the biomass of Armillaria mellea. Because of the studies, it was found that the yield of chitin-glucan complexes ranged from 11.0 to 24.9% with a degree of deacetylation from 24 to 55%. The maximum yield was obtained by treating the fruiting bodies of fungi at the stage of deproteinization with a 3% aqueous solution of sodium hydroxide with mechanical stirring at 225 rpm for 60 min at 75±5°C. It is shown that the degree of deacetylation correlates with the values of the alkali concentration used. The IR spectra of the obtained samples of chitin-glucan complexes include absorption bands characteristic of stretching and bending vibrations of the bonds of chitin and glucan links and coincide with the spectra of chitin-glucan complexes of other fungi. It has been established that the viscosity characteristics of a 1% solution of a chitin-glucan complex in 2% hydrochloric acid are 14 and 190 times lower than 5% and 10% solutions, respectively. Increasing the shear rate makes it possible to detect a decrease in the viscosity of all studied solutions. Storage of a 1% solution of chitin-glucan complexes for 7 days at 25±2°C is accompanied by a decrease in viscosity; the viscosity of 5 and 10% solutions remains stable.

Application of Keller-Box Method to the Heat and Mass Transfer Analysis of Magnetohydrodynamic Flow of Micropolar Fluid between Porous Parallel Walls of Different Permeability

The present work seeks to investigate the problem of stable laminar micropolar fluid flow through porous walls of varying permeability. Furthermore, the effect of an external magnetic field is investigated. The resulting solution is extended to analyse the nonlinear differential equation of heat and mass transfer in the flow situation. The velocity and microrotation at the channel’s entrance are assumed to be those of Poiseuille flow. Using appropriate transformations, the governing nonlinear equations are transformed to a system of ordinary differential equations, which are then solved using a novel numerical technique based on a finite difference scheme termed the Keller-box method. The results show that the smooth and straightforward Keller-box method is an appropriate method for estimating solutions of complex governing equations since it is simple to implement. Graphs and tables are used to explain the effect of significant parameters such as the suction Reynolds number, micro rotation/angular velocity parameters, and Peclet number on the stream function, temperature distribution, and concentration properties of the fluid. The effect of wall permeability on longitudinal velocity and microrotation has been investigated. The couple stress and skin friction on the walls have also been calculated. The effect of variation in Reynolds number is showing the importance of inertial forces in comparison with viscous forces. The velocity boundary layer is observed to decrease when there is an increase in Reynolds number. Furthermore, the accuracy and convergence of the obtained solutions show that the Keller-box method is applicable to various nonlinear physical problems, even those with significant non-linearity.

Molecular Modeling of the Anti-HIV Activity Mechanism of Iodine-Containing Drugs Armenicum and FS-1.

Drugs Armenicum and FS-1 are a solution of ionic nanostructured complexes of α-dextrin. In the active centers of these drugs, located inside the dextrin helix, molecular iodine has such an electronic form that minimizes toxic effects in the human body, so these drugs can be used for parenteral and oral administration. On the human lymphoblastoid cell line MT-2, the effect of the antiviral action of FS-1 against HIV-1 was established. Literature data on the results of treatment of people with HIV infection with Armenicum are presented. The mechanism of anti-HIV action of drugs Armenicum and FS-1 was proposed by the molecular modeling method. Using the DFT/B3PW91/6-31G** approach, it was shown that LiI(Cl)I2 active center drugs of Armenicum and FS-1 can be segregated from the dextrin helix and can form a complex with the ACT nucleotide triplet, which is part of a specific fragment of viral DNA that binds to the active center of integrase. The formation of this complex is a key moment in the mechanism of anti-HIV drug action. Molecular iodine and lithium halide, which are part of the active complexes, inhibit the active center of the catalytic domain of the integrase. A new nucleoprotein complex is created that destroys the nucleoprotein preintegration complex (PIC) and inhibits the HIV DNA and the active center of the catalytic domain, while a new N-I bond appears in the viral DNA in the cytosine pyrimidine cycle.

Preparation of CdS–Ag2S nanocomposites by ultrasound-assisted UV photolysis treatment and its visible light photocatalysis activity

Abstract Thiosulfate is a green leaching agent used in the hydrometallurgical process because it is both environmentally benign and can form the required soluble ion complexes. In this article, a novel method for the synthesis of CdS–Ag2S nanocomposites from a solution of relevant ion complexes via ultrasound-assisted ultraviolet (UV) photolysis was proposed. An analysis of the mechanism revealed that the complexes undergo a series of photochemical reactions. The CdS–Ag2S nanocomposites were synthesized by photochemical co-precipitation under UV-C irradiation. The microstructure, chemical composition, optical and electrochemical properties of the prepared nanocomposites were analyzed to verify the synthesis and investigate the product. The photodegradation of methyl orange (MO) under a xenon lamp was performed to determine the photocatalytic activity. Under visible light irradiation, the CdS–Ag2S nanocomposites undergo the electrons transition (from valence band to conduction band) to form photogenerated electron–hole pairs realizing the effective separation of carriers and finally promote the degradation of MO to water and carbon dioxide. The subsequent degradation efficiency of the CdS–Ag2S nanocomposites was found to be 87% after 90 min, and it was larger than 78% for pure CdS prepared via UV photolysis, indicating that the as-developed novel method can effectively fabricate CdS–Ag2S photocatalyst with superior performance.

Smart bio-nano interface derived from zein protein as receptors for biotinyl moiety

Proteinaceous, tunable nanostructures of zein (prolamine of corn) were developed as biotinyl-specific receptors using a molecular imprinting technique. Sacrificial templates, such as latex beads (LB3) and anodized alumina membrane (AAM), have been used to control nanostructural patterns in biotin-imprinted zein (BMZ). Briefly, a methanolic solution of the zein-biotin complex was drop cast upon a self-organized LB3 and AAM templates on Au/quartz surfaces. Subsequent dissolution of these sacrificial templates affords highly oriented, predetermined, and uniformly grown hyperporous (300 nm) and nanowires (150 nm) motifs of zein (BMZ-LB3 and BMZ-AAM), as shown by scanning electron microscopy (SEM). Selective extraction of biotin molecular template cast-off site-selective biotin imprints within these zein nanostructures complementary to biotinyl moieties. Alternatively, biotin-imprinted zein nanoparticles (BMZ-Np) and thin film (BMZ-MeOH) were prepared by coacervation and drop casting methods, respectively. Density functional theoretical (DFT) studies reveal strong hydrogen-bonded interaction of biotin with serine and glutamine residues of zein. Quartz crystal microbalance (QCM) studies show remarkable sensitivity of the hyperporous-BMZ-LB3 and nanowires of BMZ-AAM towards biotin derivative (biotin methyl ester) by five (24.75 ± 1.34 Hz/mM) and four (18.19 ± 0.75 Hz/mM) times, respectively, higher than the BMZ-MeOH. Enhanced permeability features of the zein nanostructures, when templated with LB3, enable the QCM detection of biotin- or its derivatives down to 12.9 ng mL−1 from dairy products (Kefir). The outcome of this study shall be a key aspect in interfacing biological materials with micro-/nano-sensors and electronic devices for detecting pertinent analytes using sustainably developed biopolymer-based nanostructures.

Functional, technological, constructive and compositional solutions of ski complexes

The article analyzes the increased interest in alpine skiing and in the design of sports ski complexes. Classifications of ski resorts, main types and their descriptions are pre-sented. Particular attention is paid to indoor ski resorts, their architectural and landscape solu-tions. The planning classification is studied in detail and presented. The article also discusses many modern engineering technologies, including: air conditioning systems, snow cooling, air dehumidification; use of safe and inexpensive lifts; technologies for making snow on a slope, cooling the snow cover and air, and dehumidifying the air. Studying the topic of ski resorts proves the importance and relevance of the design and construction of indoor multi-functional ski complexes. This presupposes a variety of space-planning solutions that ensure year-round use, and as a result, the development of territories

Photochemically induced formation of adhesive hydrogels from sodium alginate, acrylamide, and iron sandwich complexes.

Visible light irradiation of an aqueous solution of sodium alginate and organometallic complex [(C5H5)Fe(toluene)]BF4 transforms it into a rigid hydrogel due to crosslinking of the carboxylate groups by the iron ions. Irradiation of the same iron complex together with K2S2O8 initiates the polymerization of acrylamide, which provides an efficient method for light-controlled one-step preparation of alginate-polyacrylamide double network hydrogels, which are capable of gluing wet glass with 100-200 kPa shear strength.

Spectroradiometry of the Solar Corona on the RATAN-600

Modern studies of solar radio emission are complicated by continuous power amplification and multifrequency external interference, which often completely overlap important frequency ranges. Many topical problems in solar radio astronomy require large effective areas of radio telescopes, high frequency and time resolutions, accurate spatial measurements, and a large dynamic range. It becomes relevant to change the concept of receiving recording equipment. This paper deals with topical problems of the physics of the solar corona in combination with optimal methods of observation with large instruments. The features and difficulties of combining high parameters—dynamic, spatial, temporal, and frequency resolutions—are considered. The proposed solutions of the new-generation observation complex implement the possibilities of intelligent selection of registration conditions in a multioctave mode with multichannel over 8000 channels/GHz with temporary permission up to 8 ms/spectrum. A multiobject observation mode becomes available from powerful flaring objects to faint structures of various nature. High-speed data processing makes it possible to implement an online mode of interference elimination, which is based on a fast statistical analysis of the spectrum with the selection of non-Gaussian (interference) structures. Methods for high-speed analysis of large-volume data (the principal component analysis method) and their presentation to the user are proposed. Examples of the operation of the complex in the range of 1–3 GHz are given. The prospects of a new approach for multiobject radio astronomy observations in the implementation of the RATAN-600 tracking mode are considered: from recombination lines to wide-range spectra, from low-contrast fluctuations to fast changes in flares, etc.

Механизм распухания облучаемого оксидного ядерного топлива. Часть II. Распухание при скачках мощности

Analysis of swelling of large grain fuel with different additives and fission gas release from such fuel during power ramps is carried out. It is shown that the fuel swelling is phase transition of 1st kind in the supersaturated solid solution of vacancy-impurity complexes (Xe with vacancies) in uranium dioxide. Accelerated fuel swelling during power ramps is a case of thermo-kinetic effect occurred in supersaturated systems under heating/cooling.

Механизм распухания облучаемого оксидного ядерного топлива. Часть I. Режим штатного облучения

The fuel swelling during normal operation is considered within the framework of 1st kind phase transition theory. It is shown that the phase transition occurs in the supersaturated sold solution of vacancy-impurity complexes – Xe with vacancies in uranium dioxide. The analysis of fuel swelling and fission gas release from fuel doped with different additives during normal operation was carried out.

СИНЕКТИЧНИЙ ПІДХІД ДО ІНТЕЛЕКТУАЛІЗАЦІЇ ЗАБЕЗПЕЧЕННЯ ЕКОНОМІЧНОЇ БЕЗПЕКИ ПІДПРИЄМСТВА

Within the last few years, the security situation in the area of activity of Ukrainian enterprises can be considered extremely difficult, which is largely due not only to the significant impact of COVID-19 and military actions, but in general to the rapid dynamics of internal processes and changes in the operating environment. The effectiveness of previously developed protocols regarding the actions of security subjects is significantly reduced due to the increase in the share of non-standard situations, when an initiative and creative approach is required. The need for the formation of new tools in security activities is also determined by the tasks set in the conditions of Ukrainian enterprises, which are no longer limited to business protection, but involve the search for reserves and more effective use of every opportunity, which allows to improve the competitive position. The purpose of the study was to justify the methodological principles of implementing the synectic approach in the process of intellectualization of ensuring the economic security of the enterprise. In order to form the methodological principles of applying the synectic approach to the intellectualization of the economic security of the enterprise, the following methods were applied: induction and deduction, comparison and systematization – in the study of the essential characteristics of the term «synectics»; synthesis and analysis – to outline the characteristics, components and conditions of application of the synectic approach; morphological analysis – to determine the stages of implementation of the synectic group in the security activities of the enterprise; abstract-logical – for theoretical generalizations and research conclusions. Today there are known examples of the successful application of the synectic approach to the activation of innovative activities of enterprises. The study of the available experience, taking into account the real conditions of the implementation of security activities, made it possible to form the necessary methodological basis for the intellectualization of the provision of economic security of the enterprise. The main stages of the application of the synectic approach, consisting in the creation of a synectic group, training and its implantation in the security activities of the enterprise, are considered. It is proven that the creation of a synergistic group should contribute to the solution of complex and previously unknown problems based on a collective creative search for atypical options for the actions of security subjects.

Гетерометаллические (никель, титан)-содержащие диметилглиоксиматы как прекурсоры для нанесения покрытий титаната никеля

Heterometallic (nickel, titanium) dimethylglyoximate (II) with a nickel:titanium ratio of 1, was synthesized. based on nickel dimethylglyoximate (I) and titanium tetrachloride TiCl4 in chloroform The obtained complex II was characterized by XRD, IR and EPR spectroscopy, and elemental analysis. It was shown that the synthesized complex II is a solvate. On the basis of the analysis results, an assumption was made about the possible structure of complex II. It was found that the thermal decomposition of complex II starts at 44 °C. A constant mass of the decomposition product is observed in the temperature range of 590 – 850 °C. According to the XRD analysis of the thermolysis product, the main crystalline phase is nickel titanate NiTiO3, it is also present up to 5 wt. % oxides of nickel NiO and titanium TiO2, as well as carbon. Complex II was used to obtain a nickel titanate coating of a corundum substrate. A solution of complex II dissolved in dimethyl sulfoxide was applied to a preliminarily prepared surface of alumina (corundum) by immersing the substrate in the solution, after which firing was carried out at 850 °C, as a result of which the organic part (dimethylglyoxime) (III) pyrolyzed and a coating was formed. According to XRD data, the resulting coating is characterized by the perovskite structure and refers to nickel titanate. An insignificant impurity of the rutile phase was found, the content of which does not exceed 5 wt. %.

Stability of glycosylated complexes loaded with Epigallocatechin 3-gallate (EGCG)

The application of Epigallocatechin-3-gallate (EGCG) in food industry was limited by its low stability in aqueous solutions and poor bioavailability in vivo. The novel EGCG glycosylated arachin nanoparticles (Ara-CMCS-EGCG) and EGCG glycosylated casein nanoparticles (Cas-CMCS-EGCG) were prepared to improve the stability and bioavailability of EGCG. The effect of different variables on the storage stability and the slow-release behavior of novel glycosylation complexes in nanoparticle background solution and artificial gastrointestinal fluid were investigated. The results showed that the DPPH scavenging activity of Ara-CMCS-EGCG and Cas-CMCS-EGCG were stable in temperature (25 ∼ 70 °C). EGCG could enhance the crosslinking effect of molecular particles in glycosylation complexes solution. The glycosylated protein nanoparticles were stable to acid-base and enzymolysis in simulated gastrointestinal fluid. The release rate of EGCG in simulated intestinal fluid was higher than that in simulated gastric fluid. The glycosylated protein carrier can not only release EGCG slowly, but also significantly improve the stability and bioavailability of EGCG in simulated gastrointestinal fluid.

Active sites formation of molybdenum oxide catalyst for hydrocarbon conversion

The catalytic properties of molybdenum-alumina systems depend on the synthesis conditions. Herein, we considered the effect of MoO3/Al2O3 catalyst pretreatment conditions on their activity in propylene and propane conversion. MoO3/Al2O3 catalysts were synthesized by wetness impregnation of the support with a solution of molybdenum citrate complex and activated in different atmospheres at 550–590 °С. The maximum conversion of propylene and yields of metathesis products were observed for the sample activated in an inert gas flow. This is caused by the formation of precursors of the metathesis active sites in this sample, i.e. isolated surface monomolybdate species. Activation of the catalyst in hydrogen leads to the reduction of Mo6+ to Mo5+/Mo4+, which ensure the increased activity and selectivity in propane dehydrogenation. Therefore, it was shown that make it possible to purposefully change the properties of the same molybdenum-alumina catalyst to suit the problems of the specific reaction (metathesis, oligomerization, dehydrogenation, aromatization, cracking).

Nano TiO2 and Molybdenum/Tungsten Iodide Octahedral Clusters: Synergism in UV/Visible-Light Driven Degradation of Organic Pollutants.

Emissions of various organic pollutants in the environment becomes a more and more acute problem in the modern world as they can lead to an ecological disaster in foreseeable future. The current situation forces scientists to develop numerous methods for the treatment of polluted water. Among these methods, advanced photocatalytic oxidation is a promising approach for removing organic pollutants from wastewater. In this work, one of the most common photocatalysts-titanium dioxide-was obtained by direct aqueous hydrolysis of titanium (IV) isopropoxide and impregnated with aqueous solutions of octahedral cluster complexes [{M6I8}(DMSO)6](NO3)4 (M = Mo, W) to overcome visible light absorption issues and increase overall photocatalytic activity. XRPD analysis showed that the titania is formed as anatase-brookite mixed-phase nanoparticles and cluster impregnation does not affect the morphology of the particles. Complex deposition resulted in the expansion of the absorption up to ~500 nm and in the appearance of an additional cluster-related band gap value of 1.8 eV. Both types of materials showed high activity in the photocatalytic decomposition of RhB under UV- and sunlight irradiation with effective rate constants 4-5 times higher than those of pure TiO2. The stability of the catalysts is preserved for up to 5 cycles of photodegradation. Scavengers' experiments revealed high impact of all of the active species in photocatalytic process indicating the formation of an S-scheme heterojunction photocatalyst.

Highly Dispersed Ni Nanoclusters Spontaneously Formed on Hydrogen Boride Sheets.

Hydrogen boride (HB) sheets are two-dimensional materials comprising a negatively charged hexagonal boron network and positively charged hydrogen atoms with a stoichiometric ratio of 1:1. Herein, we report the spontaneous formation of highly dispersed Ni nanoclusters on HB sheets. The spontaneous reduction reaction of Ni ions by the HB sheets was monitored by in-situ measurements with an ultraviolet-visible spectrometer. Acetonitrile solutions of Ni complexes and acetonitrile dispersions of the HB sheets were mixed in several molar ratios (the HB:Ni molar ratio was varied from 100:0.5 to 100:20), and the changes in the absorbance were measured over time. In all cases, the results suggest that Ni metal clusters grow on the HB sheets, considering the increase in absorbance with time. The absorbance peak position shifts to the higher wavelength as the Ni ion concentration increases. Transmission electron microscopy images of the post-reaction products indicate the formation of Ni nanoclusters, with sizes of a few nanometers, on the HB sheets, regardless of the preparation conditions. These highly dispersed Ni nanoclusters supported on HB sheets will be used for catalytic and plasmonic applications and as hydrogen storage materials.

ПРИМЕНЕНИЕ МЕТОДА ЯМР C ПАРАМАГНИТНЫМ ДОПИНГОМ ДЛЯ ОЦЕНКИ АПОПЛАСТНОГО ПЕРЕНОСА ВОДЫ В КОРНЯХ ИНТАКТНЫХ РАСТЕНИЙ ПРИ ДЕЙСТВИИ АБИОТИЧЕСКИХ СТРЕССОВ

In this work, the methodological approach based on low-field NMR using the GdDTPA paramagnetic complex for the qualitative assessment of water transport along the apoplastic (extracellular) pathway in the roots of intact wheat plants is proposed. This approach consists in measuring the spin-spin relaxation times of the water magnetization in the roots during simultaneous incubation of the roots in a solution of the paramagnetic Gd-DTPA complex and the impact of a stress factor on the plants. During root incubation, this complex spreads only along the root apoplast system and shortens the apoplast water relaxation times. GdDTPA does not penetrate into the cells and, accordingly, does not change the intracellular water relaxation times. Thus, the rate of decrease in the relaxation times of the magnetization of apoplast water, which directly depends on the intensity of water transfer through the apoplast, can be used to determine the relative contribution of water transfer through the root apoplast during stress exposure. A twofold increase in the concentration of carbon dioxide in the aerial parts of plants was used as an abiotic factor presumably influencing the transfer of water along the root apoplast. Using this methodological approach, it was shown that increase in the CO2 concentration in the leaf zone of wheat plants to 800 ppm leads to decrease in the rate of water transfer through the root apoplast by 2–2.5 times compared with the control at ambient CO2 concentration of 400 ppm.

Assessment of the Equilibrium Constants of Mixed Complexes of Rare Earth Elements with Acidic (Chelating) and Organophosphorus Ligands

A survey of the experimental equilibrium constants in solution for the mixed complexes of 4f ions with acidic (chelating) and O-donor organophosphorus ligands published in the period between 1954 and 2022 is presented. These data are widely used in both analytical and solvent extraction chemistry. Important data evaluation criteria involved the specification of the essential reactions, process conditions and the correctness of techniques and calculations used, as well as appropriate equilibrium analysis of experimental data. Higher-quality data have been evaluated, compiled and presented herein, providing a synoptic view of the unifying theme in this area of research, i.e., synergism.