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101.
Justyna Suowska Dominika Madej Bartomiej Pokrzywka Magdalena Szumera Andrzej Kruk 《Molecules (Basel, Switzerland)》2021,26(11)
A series of silicate–phosphate glass materials from the SiO2-P2O5-K2O-MgO system (pure and doped with sulfur ions) were synthesized by melting raw material mixtures that contained activated carbon as a reducer. The bulk composition of glass was confirmed with X-ray fluorescence spectroscopy. The homogeneity of the glass was confirmed through elemental mapping at the microstructural level with scanning electron microscopy combined with an analysis of the microregions with energy-dispersive X-ray spectroscopy. The structural and optical properties of the glass were studied by using spectroscopic techniques. The infrared spectroscopy studies that were conducted showed that the addition of sulfur caused changes in the silicate–phosphate networks, as they became more polymerized, which was likely related to the accumulation of potassium near the sulfur ions. By using irradiation with an optical parametric oscillator (OPO) nanosecond laser system operating at the second harmonic wavelength, the glass samples emitted a wide spectrum of luminescence, peaking at about 700 nm when excited by UV light (210–280 nm). The influence of the glass composition and the laser-processing parameters on the emission characteristics is presented and discussed. This work also referred to the density, molar volume, and theoretical optical basicity of pure and sulfur-doped glass. 相似文献
102.
103.
Michał Terlecki Dr. Szymon Sobczak Dr. Michał K. Leszczyński Prof. Andrzej Katrusiak Prof. Janusz Lewiński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(55):13757-13764
Understanding the factors governing the formation of supramolecular structures and phase transitions between various forms of molecular crystals is pivotal for developing dynamic, stimuli-responsive materials and polymorph-controlled syntheses. Here, we investigate the pressure-induced dynamic of both the intrinsic molecular structure and the supramolecular network of a predesigned polyhedral oxo-centered zinc cluster incorporating monoanionic N,N’-diphenylformamidinate and featuring N-bonded phenyl groups in close proximity to the primary coordination sphere. We demonstrate that the model oxo cluster is prone to undergoing pressure-induced conformational transformations of the secondary coordination sphere and simultaneous stepwise (initially every second polyhedral molecule undergoes the conformational transformations) and reversible transitions from an ambient phase α to high-pressure phases β and γ, as single-crystal-to-single-crystal events. The observed phase transitions illustrate the key role of an interplay between the low-energy conformation perturbations and cooperative intra- and intermolecular noncovalent interactions. 相似文献
104.
Karolina Chrabąszcz Dr. Andrzej Błauż Martyna Gruchała Marcin Wachulec Dr. Błażej Rychlik Prof. Damian Plażuk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(20):6254-6262
Two series of the ferrocenyl and ruthenocenyl analogues of etoposide bearing 1,2,3-triazolyl or aminoalkyl linker were synthesized and evaluated for their cytotoxic properties, influence on the cell cycle, ability to induce tubulin polymerization, and inhibition of topoisomerase II activity. We found that the replacement of the etoposide carbohydrate moiety with a metallocenyl group led to organometallic conjugates exhibiting differentiated antiproliferative activity. Biological studies demonstrated that two ferrocenylalkylamino conjugates were notably more active than etoposide, with submicromolar or low-micromolar IC50 values towards SW620, etoposide-resistant SW620E, and methotrexate-resistant SW620M cancer cell lines. Moreover, the simplest ferrocenylmethylamino conjugate exerted dual inhibitory action against tubulin polymerization and topoisomerase II activity while other studied compounds affected only topoisomerase II activity. 相似文献
105.
106.
Andrzej Mianowski Izabela Baraniec-Mazurek Rafał Bigda 《Journal of Thermal Analysis and Calorimetry》2012,107(3):1155-1165
For dehydration of CaC2O4·H2O and thermal dissociation of CaCO3 carried out in Mettler Toledo TGA/SDTA-851e/STARe thermobalance similar experimental conditions was applied: 9–10 heating rates, q = 0.2, 0.5, 1, 2, 3, 6, 12, 24, 30, and 36 K min−1, for sample mass 10 mg, in nitrogen atmosphere (100 ml min−1) and in Al2O3 crucibles (70 μl). There were analyzed changes of typical TGA quantities, i.e., T, TG and DTG in the form of the relative
rate of reaction/process intended to be analyzed on-line by formula (10). For comparative purposes, the relationship between experimental and equilibrium conversion degrees was used (for
P = P\ominus P = P^{{\ominus}} ). It was found that the solid phase decomposition proceeds in quasi-equilibrium state and enthalpy of reaction is easily
“obscured” by activation energy. For small stoichiometric coefficients on gas phase side (here: ν = 1) discussed decomposition
processes have typical features of phenomena analyzable by known thermokinetic methods. 相似文献
107.
Andrzej Chmura Sven Rustler Monica Paravidino Fred van Rantwijk Andreas Stolz Roger A. Sheldon 《Tetrahedron: Asymmetry》2013,24(19):1225-1232
Enantiomerically pure (S)-mandelic acid was synthesised from benzaldehyde by sequential hydrocyanation and hydrolysis in a bienzymatic cascade at starting concentrations up to 0.25 M. A cross-linked enzyme aggregate (CLEA) composed of the (S)-selective oxynitrilase from Manihot esculenta and the non-selective nitrilase from Pseudomonas fluorescens EBC 191 was employed as the biocatalyst. The nitrilase produces approx. equal amounts of (S)-mandelic acid and (S)-mandelic amide from (S)-mandelonitrile under standard conditions, but we surprisingly found that high (up to 0.5 M) concentrations of HCN induced a marked drift towards amide production. By including the amidase from Rhodococcus erythopolis in the CLEA we obtained (S)-mandelic acid as the sole product in 90% yield and >99% enantiomeric purity. 相似文献
108.
Iwona E. Głowacka Dorota G. Piotrowska Andrzej E. Wróblewski Aleksandra Trocha 《Tetrahedron: Asymmetry》2017,28(11):1602-1607
A simple and efficient synthetic strategy to all four enantiomerically pure diethyl 1,2-di(N-Boc-amino)propylphosphonates has been elaborated starting from the corresponding N-[(R)-(1-phenylethyl)]aziridine-(2S)- and N-[(S)-(1-phenylethyl)]aziridine-(2R)-carboxaldehydes, employing a one-pot three-components Kabachnik-Fields reaction followed by the hydrogenolytic removal of the chiral auxiliary and aziridine ring opening with simultaneous protection of the amino groups as the N-Boc derivatives. 相似文献
109.
Joanna Bryś Magdalena Wirkowska Agata Górska Ewa Ostrowska-Ligęza Andrzej Bryś Piotr Koczoń 《Journal of Thermal Analysis and Calorimetry》2013,112(1):481-487
The aim of this paper was to assess the oxidative stability of structured lipids synthesized by enzymatic interesterification of a blend of lard and rapeseed oil with concentrates of n ? 3 fatty acids. Differential scanning calorimetry was used to evaluate the oxidation induction time of interesterified fats as a parameter assessing resistance of tested fats to their thermal-oxidative decomposition. Moreover, the IR spectra registered in the classic spectral range (4000–400 cm?1) were used to differentiate the samples of interesterified fats. The results show that the interesterification process decreased the induction time. Increased content polar fraction in the interesterified fatty product can reduce its resistance to oxidation. FT-IR data of selected spectral ranges correlate with the value of induction time at a statistically significant level. This is a proof that chemical changes occurring during different treatments of the starting mixture can be monitored by FT-IR spectroscopy. Moreover, obtained correlations can be used for the evaluation of an induction value of an unknown oil sample. 相似文献
110.
Góźdź Marek Góźdź Andrzej Gusev Alexander A. Vinitsky Sergue I. 《Physics of Atomic Nuclei》2018,81(6):853-857
Physics of Atomic Nuclei - We discuss the problem of the time variable in the nearly standard formulation of the quantum mechanics. In order to be able to describe the outcome of some of the... 相似文献