We synthesized UiO-67 Metal Organic Frameworks (MOFs) functionalized with bpydcPt(II)Cl2 and bpydcPt(IV)Cl4 complexes (bpydc = bipyridine-dicarboxylate), as attractive candidates for the ...heterogenization of homogeneous catalytic reactions. Pt L3-edge XAFS experiments allowed us to thoroughly characterize these materials, in the local environment of the Pt centers. XAFS studies evidenced the rich reactivity of UiO-67-Pt(II) MOFs, including reduction to bpydcPt(0) under H2 flow in the 600-700 K range, room-temperature oxidation to bpydcPt(IV)Br4 through oxidative addition of liquid Br2 and ligand exchange between 2 Cl- and even bulky ligands such as toluene-3,4-dithiol. Preliminary XANES simulations with ADF code provide additional information on the oxidation state of Pt sites.
A novel approach, which allows a refinement of 3D local structure of materials without long-range order, is described. The method is based on the quantitative analysis of X-ray absorption near edge ...structure (XANES) using multi-dimensional interpolation of spectra as a function of structural parameters. Software having user-friendly visual interface is compatible with several extensively used codes for XANES calculations: both multiple scattering muffin-tin algorithms as well as with non-muffin-tin schemes. Small number of required calculations of the spectra is the main advantage of the method, which allows to use it in combination with advanced time-expensive algorithms like full-potential schemes. Applications of the method in the fields of metalloorganic chemistry and condensed matter physics are demonstrated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The magnetic and hyperthermia characteristics and the efficiency of heating (in an alternating magnetic field) magnetite nanoparticles with different surface morphologies are investigated. Spherical, ...cubic and elongated nanoparticles are synthesized by the solvothermal method using various precursors and stabilizers. The physical-chemical and hyperthermia characteristics of the obtained nanoparticles are studied by transmission electron microscopy, X-ray diffraction, vibration magnetometry, and magnetic hyperthermia. The average sizes of the spherical, cubic, and elongated nanoparticles are 18.5, 51.6, and 34.7 nm according to X-ray diffraction data and 23, 51.6, and 46.5 × 7.3 nm according to transmission electron microscopy data, respectively. The saturation magnetization varies from 51.5 emu/g for the spherical nanoparticles up to 84 emu/g for the cubic nanoparticles; the coercive force varies from 7.8 to 52.5 Oe, respectively. The hyperthermia characteristics of magnetite nanoparticles of different morphology are determined; the intrinsic loss power is found to be
ILP
= 2.72 nH m
2
/kg for the cubic nanoparticles and 1.54 nH m
2
/kg for the spherical ones. The obtained magnetic nanoparticles of magnetite of different morphologies can be considered as potential candidates for heat mediators for local magnetic hyperthermia.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this paper we present, for the first time, a simple hydrothermal recipe for the synthesis of ZIF-8 Metal-Organic Framework (MOF) with a large specific surface area (1340 m2/g by BET). An important ...feature of the method is that the product forms in aqueous medium under standard hydrothermal conditions without DMF and great excess of linker with the use of TEA as structure directing agent. The ZIF-8 crystal phase of the product was confirmed by XRD; this technique has been also exploited to check the crystallinity and to follow the changes in the MOF structure induced by heating. TGA and temperature dependent XRD testify the high thermal stability of the material (470 °C in N2 and at 400 °C in air). The IR spectral profile of the material provides a complete picture of vibrations assigned to the linker and the metal center. The systematic investigation of the products obtained by increasing the TEA amount in the reacting medium from 0 to 25.5 mol equivalent Zn2+, allowed us to understand its role and to find 2.6 mol equivalent Zn2+ as the minimum amount needed to obtain a single phase ZIF-8 material with the high standard reported above. The stability of the material under severe basic conditions makes it a promising candidate in heterogeneous catalysis. The material has shown high capacity in I2 uptake, making it interesting also for selective molecular adsorption.
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•Successful synthesis of stable high SSA ZIF-8 MOF in aqueous solution.•Achievement of high SSA (from 1340 to 1500 m2/g by BET).•Determination of the minimum amount of TEA needed for single phase ZIF-8.•Understanding of the role of TEA as structure directing agent.•Complete, structural, textural and vibrational characterization of the whole set of samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Accurate modeling of the X-ray absorption near-edge spectra (XANES) is required to unravel the local structure of metal sites in complex systems and their structural changes upon chemical or light ...stimuli. Two relevant examples are reported here concerning the following: (i) the effect of molecular adsorption on 3d metals hosted inside metal–organic frameworks and (ii) light induced dynamics of spin crossover in metal–organic complexes. In both cases, the amount of structural models for simulation can reach a hundred, depending on the number of structural parameters. Thus, the choice of an accurate but computationally demanding finite difference method for the ab initio X-ray absorption simulations severely restricts the range of molecular systems that can be analyzed by personal computers. Employing the FDMNES code Phys. Rev. B, 2001, 63, 125120 we show that this problem can be handled if a proper diagonalization scheme is applied. Due to the use of dedicated solvers for sparse matrices, the calculation time was reduced by more than 1 order of magnitude compared to the standard Gaussian method, while the amount of required RAM was halved. Ni K-edge XANES simulations performed by the accelerated version of the code allowed analyzing the coordination geometry of CO and NO on the Ni active sites in CPO-27-Ni MOF. The Ni–CO configuration was found to be linear, while Ni–NO was bent by almost 90°. Modeling of the Fe K-edge XANES of photoexcited aqueous Fe(bpy)32+ with a 100 ps delay we identified the Fe–N distance elongation and bipyridine rotation upon transition from the initial low-spin to the final high-spin state. Subsequently, the X-ray absorption spectrum for the intermediate triplet state with expected 100 fs lifetime was theoretically predicted.
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IJS, KILJ, NUK, PNG, UL, UM
In the current work we present a detailed analysis of the hydride phase formation in industrial Pd C nanocatalysts by means of combined in situ X-ray absorption spectroscopy (EXAFS), X-ray ...diffraction (XRD) and volumetric measurements for the temperatures from - 10 to 50 °C in the hydrogen pressure range from 0 to 1000 mbar. α- and β- hydride phases are clearly distinguished in XRD. For the first time, H Pd atomic ratio were obtained by theoretical fitting of the near-edge region of the absorption spectra (XANES) and compared with volumetric measurements.
Вступ. Фармацевтична промисловість нерозривно пов’язана із науковими дослідженнями, які дозволяють оптимізувати процеси виробництва і, в першу чергу, забезпечити якість готового лікарського засобу. ...Важливим питанням технологічного процесу виробництва м’яких лікарських форм є обґрунтування технологічних параметрів виробництва (температури, часу, швидкості перемішування) на різних стадіях технологічного процесу.
Мета. Підбір технологічних параметрів (швидкості перемішування) м’яких лікарських форм на стадії фасування в умовах промислового виробництва.
Матеріали та методи. У роботі були використані фізико‐хімічні, фармакотехнологічні та статистичні методи аналізу. В якості об’єктів дослідження було використано декілька м’яких лікарських форм: паста, мазь, гель. Підбір об’єктів було проведено із урахуванням різного ступеня в’язкості даних лікарських форм. В якості діючих речовин досліджуваних лікарських форм були використані синтетичні субстанції: сірчана мазь, саліцилово-цинкова паста та гель з адапаленом. Лікарські засоби були виготовлені на кафедрі технологій фармацевтичних препаратів Національного фармацевтичного університету за загально відомим складом. Дослідження щодо реологічних властивостей дослідних зразків проводили на реовізкозиметрі компанії «Anton Paar». Статистична обробка отриманих результатів проводилась за рекомендаціями ДФУ.
Результати. За результатами досліджень визначено вплив швидкості перемішування на реологічні (динамічна та кінематична в’язкість) показники полупродуктів, що визначатиме процес роботи пристроїв фасувального апарату. Досліджено залежність зміни динамічної та кінематичної в’язкості модельних зразків м’яких лікарських форм від початку процесу фасування до виходу на сталий режим роботи обладнання. Визначено зменшення показників в’язкості полупродуктів при впливі перемішуючих пристроїв при заданій температурі.
Висновки. На основі проведених фізико‐хімічних і фармакотехнологічних досліджень та одержаних результатів було запропоновано режим роботи обладнання в умовах промислового виробництва при виробництві сірчаної мазі, саліцилово-цинкової пасти та гелю з адапаленом.
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A novel slow extraction system for the U-70 synchrotron of the IHEP (Protvino) is presented. The system has been routinely employed since 2013 to extract carbon-nuclei beams with an intermediate ...energy (455 MeV/nucleon) for applied fixed-target radiobiological research. Issues of the beam dynamics and engineering implementation of the system are considered. The results of experimental beam observations in the U-70 machine are presented, which prove the adequacy of the design approach.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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In this study, we developed a biocompatible core–shell magnetic Fe3O4@UiO-66-NH2@CisPt nanocomposite loaded with cisplatin as a therapeutic agent for drug delivery and cancer ...treatment. The nanocomposite was synthesized using a step-by-step method resulting in the formation of two phases within the core–shell structure. Advanced analytical techniques, such as XRD, HR TEM, TEM, FTIR, and VSM, were used to thoroughly analyze the structural properties, morphology, magnetic characteristics, and atomic structure of the core–shell nanocomposite. Fe3O4@UiO-66-NH2@CisPt nanocomposite exhibits superparamagnetic behavior, which is advantageous for controlled drug delivery and release by applying an external magnetic field. This study presents a significant contribution to the development of effective drug delivery systems for cancer treatment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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