Комплекс цефтриаксона с Mg(II): синтез, структура, спектральные и антибактериальные свойства

Magnesium complex of ceftriaxone was obtained and characterized by atomic-emission and elemental analysis, TGA, FTIR and Raman spectroscopy, X‑ray diffraction and density functional theory calculations. Ceftriaxone was coordinated to the magnesium ion by the oxygen of the triazine cycle in the 6th position, the nitrogen of the amine group of the thiazole ring, and oxygen atoms of the lactam carbonyl and carboxylate groups. The disodium salt of ceftriaxone and magnesium complex were screened for antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosaПолучен и охарактеризован магниевый комплекс цефтриаксона методами атомно-эмиссионного и элементного анализов, ТГА, ИК- и КР‑спектроскопии, РФА и расчетов теории функционала плотности. Цефтриаксон координируется к иону магния через кислород триазинового цикла в шестом положении, азот аминогруппы тиазольного цикла и атомы кислорода карбоксильной и лактамной групп. Динатриевая соль цефтриаксона и комплекс магния были исследованы на антибактериальную активность в отношении Staphylococcus aureus, Escherichia coli и Pseudomonas aeruginos

Determination of metals in natural waters by inductively coupled plasma optical emission spectroscopy after preconcentration on silica sequentially coated with layers of polyhexamethylene guanidinium and sulphonated nitrosonaphthols

A series of complexing adsorbents is prepared by coating silica particles with linear polyhexamethylene guanidinium (PHMG) chloride followed by saturation with a number of sulphonated nitrosonaphthols reagents electrostatically retained by positively charged polymer layer. PHMG coated silica is hydrolytically stable even during treatment with 6 M HCl heated up to 50 °C. The adsorption of 1-nitroso-2-naphthol-3,6-disulfonic acid (nitroso-R-salt), 2-nitroso-1-naphthol-4-sulfonic acid (nitroso-N-salt), and 2-nitroso-1-naphthol-3,6-disulfonic acid (nitroso-K-salt) on PHMG modified silica was studied. The effective immobilisation of sulphonated nitrosonaphthols was achieved in the range of pH of 3 - 8, while the adsorption of the monosulphonated reagent (nitroso-N-salt) is twice as high as the disulphonated analogues (nitroso-R-salt and nitroso-K-salt). The adsorption of Cu(II), Fe(III), Co(II), Ni(II), Al(III), Zn(II), Pb(II), Mn(II), and Cr(III) on prepared complexing adsorbents under static and dynamic conditions was studied as a function of time, pH, sample volume, and presence of interfering ions. Metal ions can be desorbed by using 1 M HCl or 1 M HNO3. The preconcentration factors of metals under optimized conditions are varied from 20 to 80. The developed method was used for the preconcentration of trace metals from natural waters followed by ICP-OES determination. The sub-ppb limits of detection of metals are achieved. © 2019 Svetlana L. Didukh-Shadrina et al

Effect of Polysaccharide Additions on the Anion-Exchange Deposition of Cobalt Ferrite Nanoparticles

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.A facile and rapid method easily reproducible in ordinary laboratory settings is proposed for preparing nanosized cobalt ferrite powders, where the precipitate used is a strongly basic anion exchange resin in the OH form. The effects caused by additions of polysaccharides having various chain natures and various molar weights on the composition, yield, and particle size of the deposition product are studied. Suggested mechanisms underlying these effects are studied. This method makes it possible to appreciably reduce the precursor annealing temperature compared to that in the state-of-art methods for preparing similar oxide systems due to the formation of highly reactive precursors. Optimal conditions are found to prepare stoichiometric precursors such that, once annealed at 600°C, would form a CoFe2O4 pure phase with particle sizes of 10–20 nm. The stability of hydrosols of the thus-prepared cobalt ferrite nanoparticles is studied by dynamic and electrophoretic light scattering. The prepared material is found to be useful for the design of magnetic core–shell hybrid nanostructures. © 2020, Pleiades Publishing, Ltd

Influence of alkyl substituents in 1,3-diethyl-2-thiobarbituric acid on the coordination environment in M(H2O)(2)(1,3-diethyl-2-thiobarbiturate)(2) M = Ca2+, Sr2+

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Two new isostructural complexes, [Ca(H2O)(2) (mu(2)-Detba-O,O')(2)](n) (1) and [Sr(H2O)(2)(mu(2)-Detba-O,O')(2)](n) (2) (HDetba = 1,3-diethyl-2-thiobarbituric acid), were synthesized and characterized by single-crystal and powder X-ray diffraction analysis, TG-DSC, FT-IR, and emission spectroscopy. The single-crystal X-ray diffraction data revealed that 1 and 2 are polymeric where M2+ (M = Ca, Sr) is a six-coordinate octahedral binding four Detba(-) ions and two water molecules. The octahedra are linked through bridging Detba(-) ions forming a 2-D layer. Two intermolecular hydrogen bonds O-H center dot center dot center dot S in the crystal form a 3-D net. The comparison of M(Detba)(2) and M(Htba)(2) (H(2)tba = 2-thiobarbituric acid) structures showed that the coordination number of metals in M(Detba)(2) does not exceed six and there are no pi-pi interactions, unlike compounds with Htba(-); Detba(-) ions are only bridges in HDetba coordination compounds. Thermal decomposition of 1 and 2 includes dehydration, which mainly ends at 200 degrees C, and organic ligand oxidation at 300-350 degrees C with a release of CO2, SO2, H2O, NH3, and isocyanate. Upon excitation at 220 nm, 1 and 2 exhibit an intense emission maximum at 557 nm

Influence of alkyl substituents in 1,3-diethyl-2-thiobarbituric acid on the coordination environment in M(H2O)(2)(1,3-diethyl-2-thiobarbiturate)(2) M = Ca2+, Sr2+

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Two new isostructural complexes, [Ca(H2O)(2) (mu(2)-Detba-O,O')(2)](n) (1) and [Sr(H2O)(2)(mu(2)-Detba-O,O')(2)](n) (2) (HDetba = 1,3-diethyl-2-thiobarbituric acid), were synthesized and characterized by single-crystal and powder X-ray diffraction analysis, TG-DSC, FT-IR, and emission spectroscopy. The single-crystal X-ray diffraction data revealed that 1 and 2 are polymeric where M2+ (M = Ca, Sr) is a six-coordinate octahedral binding four Detba(-) ions and two water molecules. The octahedra are linked through bridging Detba(-) ions forming a 2-D layer. Two intermolecular hydrogen bonds O-H center dot center dot center dot S in the crystal form a 3-D net. The comparison of M(Detba)(2) and M(Htba)(2) (H(2)tba = 2-thiobarbituric acid) structures showed that the coordination number of metals in M(Detba)(2) does not exceed six and there are no pi-pi interactions, unlike compounds with Htba(-); Detba(-) ions are only bridges in HDetba coordination compounds. Thermal decomposition of 1 and 2 includes dehydration, which mainly ends at 200 degrees C, and organic ligand oxidation at 300-350 degrees C with a release of CO2, SO2, H2O, NH3, and isocyanate. Upon excitation at 220 nm, 1 and 2 exhibit an intense emission maximum at 557 nm

Electrochemical Behaviour of Cu-Al Oxygen-Evolving Anodes in Low-Temperature Fluoride Melts and Suspensions

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Cu-based alloys have been considered as promising candidates (along with the Fe-Ni alloys) for the inert anodes material in aluminium reduction cells with low-temperature electrolytes. However, low purity of aluminium due to the contamination by anode corrosion products is a problem yet to be solved. Introduction of alumina suspension as an electrolyte has been presented recently as a possible solution for providing commercial purity aluminium produced with the metallic anode. An attempt to characterize the CuAl-based anodes electrochemical performance in KF-AlF3-Al2O3 melts and suspensions has been made and presented. The effects of the suspension (or melt) properties, the anode composition and the temperature on the electrochemical behaviour of the anode and the kinetics of the oxide layer formation during polarization are studied. The 90Cu-10Al anode in the KF-AlF3-Al2O3 suspension with the cryolite ratio 1.3 and the dispersed phase volume fraction not more than 0.12 is found to be the good option for further investigations. © 2020, The Minerals, Metals & Materials Society

The Use of Porous Silicate Materials with Different Structures for Acetalization of Furfural and 5-Hydroxymethylfurfural by Methanol

Изучено селективное ацеталирование фурфурола и 5-гидроксиметилфурфурола метанолом в присутствии гетерогенных катализаторов на основе диоксида кремния. Произведено сопоставление каталитической активности силикатных материалов единой химической природы (MCM-41, SBA-15 и силикагель) в реакциях ацеталирования фурфурола и 5-гидроксиметилфурфурола метанолом со структурными и текстурными свойствами катализатора. Мезоструктурированные силикатные материалы (MCM-41, SBA-15) позволяют получить метилацетали фурфурола и 5-гидроксиметилфурфурола с выходами 80–95 % от теоретического с селективностью до 98 %Selective acetalization of furfural and 5-hydroxymethylfurfural by methanol in the presence of silica catalysts was investigated. Catalytic activity of silica materials (MCM-41, SBA-15, and silicagel) in reaction of furfural and 5-hydroxymethylfurfural acetalization by methanol was brought into correlation with its structure and textural properties. Mesostructured silica materials (MCM-41, SBA- 15) allow obtaining of furfural and 5-hydroxymethylfurfural methylacetals with the 80-95 % yield and up to 98 % selectivit

Structure of bis(2-Thiobarbiturate)Tris (2,2-Bipyridyl)Nickel(II) Hexahydrate

The [Ni(Bipy) 3 ](Htba) 2 ·6H 2 O (I) complex (Bipy is 2,2′-bipyridyl, H 2 tba is 2-thiobarbituric acid) is synthesized and its structure is determined by single crystal XRD (cif-file CCDC No. 1836529). The crystals of I are monoclinic: a = 13.6618(6) Å, b = 23.9441(9) Å, c = 25.4335(8) Å, β = 93.091(1)°, V = 8307.7(5), space group P2 1 /c, Z = 8. Via multiple intermolecular N–H⋯O, O–H⋯O, and C–H⋯S hydrogen bonds (HBs), the Htba − ions and water molecules form channels within which [Ni(Bipy) 3 ] 2+ cations are located. The Bipy molecules and the Htba − ions are involved in C–H⋯O HBs and the π−π interaction. The results of the thermal analysis and IR spectroscopy agree with the single crystal XRD data. © 2019, Pleiades Publishing, Ltd

Structural aspects of the formation of solid solutions in the NaF-KF-AlF3 System

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала