STUDY ON NEW COMPLEX COMPOUNDS OF Ti(IV) AND Zr(IV) IN AQUEOUS SOLUTIONS: SYNTHESIS, STABILITY AND APPLICATION IN CLEANER TECHNOLOGIES OF NATURAL LEATHER

2008 ◽  
Vol 7 (3) ◽  
pp. 241-248 ◽  
Author(s):  
Doina Sibiescu ◽  
Ioan Rosca ◽  
Daniel Sutiman ◽  
Marian Crudu ◽  
Adrian Cailean ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Complex Compounds ◽  
Cleaner Technologies

121,123Sb and 209Bi Nuclear Quadrupole Resonance Study of Complex Compounds of Antimony(III) and Bismuth(III) in the Temperature Range 77-400 K

1998 ◽  
Vol 53 (6-7) ◽  
pp. 573-584 ◽  
Author(s):  
L. A. Zemnukhova ◽  
R. L. Davidovich
Keyword(s):  
Aqueous Solutions ◽  
Nuclear Quadrupole Resonance ◽  
Crystal Structures ◽  
Wide Temperature Range ◽  
Complex Compounds ◽  
Temperature Range ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract A large number of solid fluoride and heteroligand acidocomplex compounds of antimony(III) and bismuth(III) with single and mixed cations has been prepared from aqueous solutions. Their crystal structures and 121,123Sb and 209Bi NQR spectra have been investigated in a wide temperature range.

scholarly journals ELECTRODEPOSITION OF METALS AND ALLOYS FROM AQUEOUS SOLUTIONS. REVIEW OF WORK OF EMPLOYEES FROM V.I. VERNADSKY NASU

2021 ◽  
Vol 87 (7) ◽  
pp. 32-46
Author(s):  
Valeriy Kublanovsky ◽  
Oksana Bersirova
Keyword(s):  
Aqueous Solutions ◽  
Protective Coatings ◽  
Complex Compounds ◽  
Metals And Alloys ◽  
Theory And Practice ◽  
Power Sources ◽  
Chemical Power Sources ◽  
Anticorrosion Coatings ◽  
The Relationship ◽  
Electrodeposition Of Metals

The article examines in a historical perspective the issues that have been associated with the theory and practice of electrochemical deposition over the years of existence of the V.I. Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine. Research in the field of electrochemistry of aqueous solutions, which was and is being carried out at the Institute, made a significant contribution to theoretical and applied electro­chemistry: the theory of electrode pro­cesses, electrochemistry of complex compounds, masstransfer, chemical power sources, electrocatalysis, electrochemical devices, theoretical and engineering electroplating, hydroelectro­metallurgy, electrochemical ecology and a number of other areas of modern chemistry. This article highlights issues related to research in the field of electrodeposition, namely: theo­retical research in the field of electrodeposition, electrodeposition of metals and alloys, hydroelectrometallurgy, corrosion and anticorrosion coatings. It is proved the effect of complexation leads to the formation of elect­rochemically active and inactive coordination ions, a mechanism for the discharge of ions during the formation of a film on the electrode surface is also proposed. The regularities leading to the formation of powders and black deposits of metals are analyzed. The conditions for a stable electrolysis regime were identified, the concept of the electrochemical resistance of the system was introduced, and the relationship between the kinetic parameters of elect­rolysis and the structure of the coatings was shown. The works in the field of hydroelectrometallurgy, corrosion-resistant and protective coatings are analyzed. It is noted that the scien­tific achievements of the Institute’s scientists are widely known around the world.

scholarly journals STABILITY CONSTANTS OF L-ASPARAGINE AND L-LEUCINE COMPLEXES WITH SOME LANTHANIDE IN AQUEOUS SOLUTIONS AT 298.15 K

2017 ◽  
Vol 61 (1) ◽  
pp. 37
Author(s):  
Alexandr I. Lytkin ◽  
Natalya V. Chernyavskaya ◽  
Darya K. Smirnova
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Quantitative Estimation ◽  
A Priori ◽  
Complex Compounds ◽  
Complexing Agent ◽  
Stability Of Complexes ◽  
Biological Substrates ◽  
The Stability

Lanthanides have a high affinity toward ligands containing donor oxygen atoms, especially amino acids and complexons. The study of the processes of complexation of amino acids with f-element cations provides valuable information for solving problems of supramolecular chemistry, molecular recognition and chiral sensitivity of biological substrates. As a rule, f-elements are not components of biopolymers, but they are spectral label probes, which are important in the bioinorganic chemistry of metals. Quantitative estimation of the stability of complexes is necessary, first of all, to search for an internal connection between the constants themselves and then to find correlations between the stability of complexes and the properties of the complexing agent, the ligand, and the system as a whole. Such correlation dependencies make it possible to calculate a priori, or at least estimate the stability constants of new complexes, and also to better understand the influence of the nature of the chemical bond and the properties of the system as a whole on the formation and stability of complex compounds. In the present work, the complexation of neodymium, lanthanum with L-asparaginat ion and samarium, cerium with L-leucinat ion at 298.15 K and ionic strength values of 0.5 mol/l was studied by potentiometric titration and the stability constants of the complexes formed were determined. The values of the stability constants found allow us to perform rigorous thermodynamic calculations of the equilibria of these amino acids in salt solutions. The data obtained, in particular, can be used to reliably interpret the results of calorimetric studies of the complexation of lanthanides with the participation of the studied amino acids.Forcitation:Lytkin A.I., Chernyavskaya N.V., Smirnova D.K. Stability constants of L-asparagine and L-leucine complexes with some lanthanide in aqueous solutions at 298.15 K. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 37-41

scholarly journals THERMAL STUDY OF SOLID COMPLEXES OF CERIUM, PRASEODIUM AND NEODIUM

2020 ◽  
pp. 41-45
Author(s):  
Тимофей Владимирович Крюков ◽  
Михаил Игоревич Скобин ◽  
Мариана Александровна Феофанова ◽  
Владимир Георгиевич Алексеев
Keyword(s):  
Thermal Analysis ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Aqueous Solutions ◽  
Sodium Salt ◽  
Complex Compounds ◽  
Thermal Study ◽  
Synchronous Thermal Analysis ◽  
Cefazolin Sodium ◽  
Solid Complexes

Взаимодействием водных растворов хлоридов соответствующих редкоземельных элементов и натриевой соли цефазолина (NaCzl) были получены и выделены в твердом виде комплексные соединения цефазолина. Полученные комплексы имеют состав Me(Czl)•3HO, где Me = Ce+, Pr+, Nd+. Полученные соединения исследованы методом синхронного термического анализа. By the interaction of aqueous solutions of the chlorides of the corresponding rare-earth elements and the cefazolin sodium salt (NaCzl), complex compounds of cefazolin were obtained. The resulting compounds were investigated by synchronous thermal analysis.

scholarly journals The influence of nature of active components and modifiers on electroanalytic properties of planar cefalexine-selective sensors

2021 ◽  
Vol 21 (2) ◽  
pp. 134-144
Author(s):  
Elena G. Kulapina ◽  
◽  
Olga I. Kulapina ◽  
Vlada D. Ankina ◽  
◽  
...  
Keyword(s):  
Response Time ◽  
Aqueous Solutions ◽  
Oral Fluid ◽  
Cupric Oxide ◽  
Active Material ◽  
Complex Compounds ◽  
Active Components ◽  
Kinetic Spectrophotometry ◽  
Biological Environment

The 1st generation cefalexine-cephalosporine antibiotic is used in the treatment of various infectious diseases. Spectrophotometry, kinetic spectrophotometry, spectrofluorimetry are proposed to determination of cefalexine in medicine and biological environment. Planar screenprinted sensors allow analyzing the micro-volumes of samples, which is important for the analysis of biological objects without preliminary samplepreparation. Depending on the active material and modifiers, you can create planar sensors for the determination of different organic compounds. In this work we have studied the influence of the nature of electroactive compounds and modifiers on the electroanalytic properties of planar cefalexine-selective sensors. Associates of tetradecylammonium and dimethyldistearylammonium with complex compounds silver (1) – cefalexine (Ceas = 1–3%), polyaniline modifiers and cupric oxide nanoparticles have been used as active components, the ratio EAS: modifier is 1:1. The main electroanalytic and operational characteristics of cefalexine-selective sensors in aqueous solutions and on the background of oral fluid are determined. Advantage of tetradecylammonium in active components of cefalexine-selective sensors is shown. For cefalexine- sensors, the optimal is: linearity interval 1·10-2 – 1·10-4, response time 20–25 seconds, for unmodified: 10–15 sec, for modified in 1·10-2 M solutions of cefalexine, service life – 1 month. Modifiers approximate angular coefficients of electrode functions to theoretical values for single-charge ions, reduce response time and drift of potential, reduce the detection limit of cefalexine. Sensors are used for the determination of cephalexine in model aqueous solutions and oral fluid with added antibiotic additives, in expired cephalexine preparations.

scholarly journals Physico-chemical interaction patterns of oxidized polyvinyl alcohol fraction with 4- and 5-aminosalicylic acids

2019 ◽  
Vol 58 (4) ◽  
pp. 77-84
Author(s):  
Galia G. Kutlugildina ◽  
◽  
Zalia F. Ramazanova ◽  
Yury S. Zimin ◽  
◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Chemical Interaction ◽  
Average Molecular Weight ◽  
Complex Compounds ◽  
Interaction Patterns ◽  
Aminosalicylic Acid ◽  
Temperature Range ◽  
Aminosalicylic Acids

The interaction of the oxidized fraction of polyvinyl alcohol (OF of PVA) with 4- and 5-aminosalicylic acids (4- and 5-ASA) in aqueous solutions was examined by ultraviolet spectroscopy. OF of PVA is obtained by oxidation of polyvinyl alcohol in an aqueous medium affected by hydrogen peroxide (363 K, [PVA] = 3.5% wt., [H2O2] = 1 mol/l, toxid. = 45 min), further separated from the solution by acetone addition. The average molecular weight of the oxidized fraction of PVA, calculated from the experimentally found value of the characteristic viscosity using the Mark-Kun-Houwink equation, amounted to 4.5 kDa. It was found that the addition of the original (non-oxidized) polyvinyl alcohol to aqueous solutions of 4- and 5-ASA does not change their UV spectra. At the same time, the introduction of an oxidized fraction of polyvinyl alcohol into aqueous solutions of aminosalicylic acids leads to spectral changes, indicating intermolecular interactions and complexation. By the method of molar ratios, it was shown that in dilute aqueous solutions OF of PVA forms complex 1 : 1 compounds with 4-ASA and 5-ASA, i.e., one molecule of 4- or 5-aminosalicylic acid accounts for one carboxyl group of the oxidized PVA fraction. Using this method, in the 291-316 K temperature range, the stability constants (K) of the resulting complex compounds were calculated. The results analised demonstrated that the oxidized fraction of polyvinyl alcohol forms strong enough complexes with 4- and 5-aminosalicylic acids: the K values in the temperature range under study vary within (1-7)∙104 l/mol. It was found out that with increasing temperature, the values of stability constants of complex compounds decrease. The study of the temperature dependence of K made it possible to determine the standard values of the changes in the Gibbs energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) of complexing. Negative values of thermodynamic parameters indicate a spontaneous process of formation of complexes, their exothermicity and the resulting constraints of the movements of molecules.

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