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Anions of phosphoric acid are nutrients. They are necessary for people, animals or plants to ensure normal life. The combination of biochemical and various membrane methods with electrodialysis as a fi nishing step for selective extraction and concentration of nutrients has already proved its economic and environmental feasibility. The complexity of experimental and theoretical studies of the phosphate transfer mechanisms in systems with ion-exchange membranes is because the amphoteric properties of this substance. This work is aimed to investigate the transfer mechanisms in the desalting channels of electrodialyzers containing NaH2PO4 solution. The object of the study is the homogeneous anion exchange membrane AX in a 0.02 M NaH2PO4 solution. Due to the protonation-deprotonation reactions of the dihydrogen phosphate anion, the last can be transformed into hydrogen phosphate and phosphate anions with the formation of protons and hydroxyl ions, which can participate in the charge transfer in the AX/NaH2PO4 system. As a result, the transport of phosphates in systems with ion-exchange membranes is characterized by anomalous (in comparison with NaCl solutions) concentration dependences of electrical conductivity, diffusion permeability, and current-voltage characteristics, which have two plateaus. In this paper, we propose a simple method that allows us to determine the partial currents and transport numbers of counter ions through the anion exchange membrane, and to estimate the number of protons coming from the membrane boundary into the desalting channel of the electrodialyzer in the under-limiting and over-limiting current modes. Using this method, it was found that the transformation of single-charged anions H PO 2 4- in the membrane fi rst into double-charged HPO4 2- and then into triple-charged PO4 3- ions causes differences in the shape of the total current-voltage characteristics in comparison with obtained in NaCl solutions.

The article clarifies the meaning of the terms accuracy and reliability of the news story, offers a researcher's approach to obtaining objective data that helps to verify linguistic means of accuracy and reliability presence in the informative structure of the text. The accuracy of the news story is defined as a high relevance degree of event reflection through language representation of its constituents; the reliability is viewed as news story originality that is proved by introducing citations and sources of information considered being trustworthy into the text content. Having based the research on an event nominative density identification method, the author composed nominative charts of 115 news story texts, collected at web-sites of BBC and CNN media corporations; distinguished qualitative and quantitative markers of accuracy and reliability in the news story text; confirmed that the accuracy of the news story is achieved with terminological clearness in nominating event constituents in the text, thematic bind between words, presence of onyms that help deeply identify characteristics of the referent event. The reliability of the text is discovered in eyewitness accounts, quotations, and references to the sources being considered as trustworthy. Accurate revision of associations between accuracy and reliability and informing strategies in digital news nets allowed the author to set two variants of information delivery, that differ in their communicative and pragmatic functions: developing (that informs about major and minor details of an event) and truncated (which gives some details thus raising the interest to the event and urging a reader to open a full story).

In article the ways of adaptation of elements of improvement, and also replacement of monolithic and stationary parts of the equipment on flexible, transformed designs were analyzed. The main prerequisites for a qualitative change in the urban environment are the actual needs of the population: unhindered access to the objects of the mass service system (hereinafter MSS), safe movement on transport and pedestrian routes from residential areas to gravity focuses, the possibility of orientation, barrier-free communication and communication with dispatching service organizations in emergency situations through multimedia resources [7]. The main methods of research in the current article are full-scale surveys, interviewing the target audience with a preliminary sample. The article considers a set of solutions for the adaptation of the territory to the needs of PWLM by means of transformable structures [17]. Standardization of structures and equipment will allow to achieve better quality, more ergonomic solutions in the equipment of objects of different categories and purposes, unification of prefabricated elements-their serial production with the state control of products. Such organization of improvement will allow to achieve sustainable development of urban areas for the project period, will create a basis for future generations.

A new synthetic pathway is devised to selectively produce previously elusive heteroleptic iron(II) complexes of terpyridine and N , N '-disubstituted bis(pyrazol-3-yl)pyridines that stabilize the opposite spin states of the metal ion. Such a combination of the ligands in a series of the heteroleptic complexes induces the spin-crossover (SCO) not experienced by the homoleptic complexes of these ligands or shifts it to lower/higher temperatures respective to the SCO-active homoleptic complex. The midpoint temperatures of the resulting SCO span from ca. 200 K to the ambient temperature and beyond the highest temperature accessible by NMR spectroscopy and SQUID magnetometry. The proposed "one-pot" approach is applicable to other N -donor ligands to selectively produce heteroleptic complexes─including those inaccessible by alternative synthetic pathways─with highly tunable SCO behaviors for practical applications in sensing, switching, and multifunctional devices.

A recently introduced concept of reduced paramagnetic shifts (RPS) in NMR spectroscopy is applied here to a series of paramagnetic complexes with different metal ions, such as iron(II), iron(III) and cobalt(II), in different coordination environments of N-donor ligands, including a unique trigonal-prismatic geometry that is behind some record single-molecule magnet behaviours. A simple, almost visual analysis of the chemical shifts as a function of temperature, which is at the core of this approach, allows for a correct signal assignment and evaluation of the anisotropy of the magnetic susceptibility, the key indicator of a good single molecule magnet, that often cannot be done using traditional techniques rooted in quantum chemistry and NMR spectroscopy. The proposed approach thus emerged as a powerful alternative in deciphering the NMR spectra of paramagnetic compounds for applications in data processing and storage, magnetic resonance imaging and structural biology.

Here, we report a combined study of the effects of two chemical modifications to an N , N '-disubstituted bis(pyrazol-3-yl)pyridine (3-bpp) and of different solvents on the spin-crossover (SCO) behavior in otherwise high-spin iron(II) complexes by solution NMR spectroscopy. The observed stabilization of the low-spin state by electron-withdrawing substituents in the two positions of the ligand that induce opposite electronic effects in SCO-active iron(II) complexes of isomeric bis(pyrazol-1-yl)pyridines (1-bpp) was previously hidden by NH functionalities in 3-bpp precluding the molecular design of SCO compounds with this family of ligands. With the recent SCO-assisting substituent design, the uncovered trends converged toward the first iron(II) complex of N , N '-disubstituted 3-bpp to undergo an almost complete SCO centered at room temperature in a less polar solvent of a high hydrogen-bond acceptor ability., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

An approach to activating Pd-complexes without using additives such as Lewis acids has been developed for addition polymerization of norbornenes. Aryl iodides and aryl diazonium salts were efficiently applied as cocatalysts to Pd(0)- and Pd(2+)-complexes. The developed systems catalyzed polymerization of norbornenes containing bulky and polar functional groups both in an inert atmosphere and air resulting in soluble and high-molecular-weight saturated polymers.

The condensation of primary amines with N -(1-(4-hydroxy-6-methyl-2-oxo-2 H -pyran-3-yl)-2-oxo-2-arylethyl)acetamides was explored. Thus, a previously unknown recyclization of the starting material was observed in acidic ethanol in the presence of an amine, which provided the corresponding dihydropyrrolone derivative as the major reaction product. Based on this transformation, a practical and convenient one-pot synthetic method for substituted pyrrolo[3,4- b ]pyridin-5-ones could be devised., (Copyright © 2019, Melekhina et al.; licensee Beilstein-Institut.)

A series of novel (NHC)PdCl 2 -PR 3 complexes were synthesized and fully characterized by 1 H, 13 C, 31 P NMR and FT-IR spectroscopy. These complexes showed high catalytic activity toward solvent-free Buchwald-Hartwig amination. Both primary and secondary amines were efficiently utilized under the same reaction conditions. The solvent-free synthesis of valuable N-aryl carbazoles and similar N-heterocyclic systems was described.