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991.
Nitrato complexes of copper(II) with 1-ethoxymethyl- imiazole (L), of general formulae CuL2(NO3)2 (1) and CuL4(NO3)2 (2) have been prepared and characterized by elemental analysis and by i.r., f.i.r., vis-n.i.r. spectral evidence, conductivity, magnetochemical measurements and single crystal X-ray analysis. Compound (1) has two 1-ethoxymethylimidazole molecules and two bidentate nitrato groups in the copper(II) co-ordination sphere. In complex (2) the immediate surroundings of copper(II) is described by a tetragonally elongated octahedron with the difference the horizontal and equatorial bond lengths of 0.462 Å. 相似文献
992.
In a series of our previous papers we have investigated the influence of various variables on retention/migration of peptides in various high-performance thin-layer chromatography (HPTLC) and pressurized planar electrochromatography (PPEC) systems. Here we present a correlation of the selectivity of peptide separation in similar, as well as in various HPTLC and PPEC systems investigated before. Our results show that the selectivity in similar HPTLC and PPEC systems is quite different. This results from the share of electrophoresis in separation of solutes by PPEC. The results suggest that combination of HPTLC and PPEC, with properly selected separation conditions (the same, or even better—different for each technique), may be used for efficient two-dimensional separation of peptides. The best separation can be obtained if PPEC is carried out in two opposite directions (toward the cathode and the anode) simultaneously. 相似文献
993.
Amanda Kulpa Jacek Ryl Grzegorz Skowierzak Adrian Koterwa Grzegorz Schroeder Tadeusz Ossowski Pawe Niedziakowski 《Electroanalysis》2020,32(3):588-597
This study describes the synthesis and characterization of ethylenediaminetetraacetic acid (EDTA) functionalized magnetic nanoparticles of 20 nm in size – Fe3O4@SiO2‐EDTA – which were used as a novel magnetic adsorbent for Cd(II) and Pb(II) binding in aqueous medium. These nanoparticles were obtained in two‐stage synthesis: covering by tetraethyl orthosilicate and functionalization with EDTA derivatives. Nanoparticles were characterized using TEM, FT‐IR, and XPS methods. Metal ions were detected under optimized experimental conditions using Differential Pulse Anodic Stripping Voltammetry (DPASV) and Hanging Mercury Drop Electrode (HDME) techniques. We compared the ability of Fe3O4@SiO2‐EDTA to bind cadmium and lead in concentration of 553.9 μg L?1 and 647.5 μg L?1, respectively. Obtained results show that the adsorption rate of cadmium binding was very high. The equilibrium for Fe3O4@SiO2‐EDTA‐Cd(II) was reached within 19 min while for the Fe3O4@SiO2‐EDTA‐Pb(II) was reached within 25 minutes. About 2 mg of nanoparticles was enough to bind 87.5 % Cd(II) and 54.1 % Pb(II) content. In the next step the binding capacity of Fe3O4@SiO2‐EDTA nanoparticles was determined. Only 1.265 mg of Fe3O4@SiO2‐EDTA was enough to bind 96.14 % cadmium ions while 5.080 mg of nanoparticles bound 40.83 % lead ions. This phenomenon proves that the studied nanoparticles bind Cd(II) much better than Pb(II). The cadmium ions binding capacity of Fe3O4@SiO2‐EDTA nanoparticles decreased during storage in 0.5 M KCl solution. Two days of Fe3O4@SiO2‐EDTA storage in KCl solution caused the 32 % increase in the amount of nanoparticles required to bind 60 % of cadmium while eight‐days storage caused further increase to 328 %. The performed experiment confirmed that the storage of nanoparticles in solution without any surfactants reduced their binding capacity. The best binding capacity was observed for the nanoparticles prepared directly before the electrochemical measurements. 相似文献
994.
Dr. Anzhela Galstyan Dr. Yogesh Kumar Maurya Dr. Halina Zhylitskaya Youn Jue Bae Dr. Yi-Lin Wu Prof. Dr. Michael R. Wasielewski Prof. Dr. Tadeusz Lis Prof. Dr. Ulrich Dobrindt Prof. Dr. Marcin Stępień 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(37):8262-8266
Free base, zinc and palladium π-extended porphyrins containing fused naphthalenediamide units were employed as photosensitizers in antimicrobial photodynamic therapy (aPDT). Their efficacy, assessed by photophysical and in vitro photobiological studies on Gram-positive bacteria, was found to depend on metal coordination, showing a dramatic enhancement of photosensitizing activity for the palladium complex. 相似文献
995.
The main advantage of the application of cyclic chronopotentiometry (CCP) in end-column CE detection arises from the fact that the detection parameters and the magnitude of the analytical signal are (in contrast with other electrochemical detection methods) independent of the ohmic polarization of the solution caused by the separation current at the detection end of the capillary. CCP was used to determine sugars on platinum and gold microelectrodes after separation by CE. The results obtained with a gold microelectrode were better. Subsequently this detection method was used for quantitative determination of sugars in honeys and for their authentication. 相似文献
996.
We investigate a population of individuals who play the Rock–Paper–Scissors (RPS) game. The players choose strategies not only by optimizing their payoffs, but also taking into account the popularity of the strategies. For the standard RPS game, we find an asymptotically stable polymorphism with coexistence of all strategies. For the general RPS game we find the limit cycles. Their stability depends exclusively on two model parameters: the sum of the entries of the RPS payoff matrix, and a sensitivity parameter which characterizes the personality of the players. Apart from the supercritical Hopf bifurcation, we found the subcritical bifurcation numerically for some intervals of the parameters of the model. 相似文献
997.
We prove that the set of all complex series which are nonabsolutely convergent is c-algebrable. We establish a similar result for the set of all divergent complex series with bounded partial sums. 相似文献
998.
Jaroslava Maroszová Jan Moncol Zdeňka Padělková Reijo Sillanpää Tadeusz Lis Marian Koman 《Central European Journal of Chemistry》2011,9(3):453-459
The crystal and molecular structure of [Cu(nif)2(4-PM)2]·CH3OH (1) and [Cu(2-Clbz)2(4-PM)2(H2O)] (2), (where nif = niflumate anion, 2-Clbz = 2-chlorobenzoate anion and 4-PM is the 4-pyridylmethanol), have been determinated
by X-ray crystallography. The Cu2+ cation in (1), is coordinated by two pairs of oxygen atoms from asymmetric bidentate niflumate anions and by a pair of pyridine
nitrogen atoms from monodentate 4-pyridylmethanol ligands in trans position forming an extremely elongated bipyramid. The
Cu2+ cation in (2), is coordinated by a pair of oxygen atoms from monodentate 2-chlorobenzoate anions, further by a pair of pyridine
nitrogen atoms from monodentate 4-pyridylmethanol ligands and finally by a water oxygen atom forming a tetragonal-pyramidal
coordination polyhedron. The molecules of both complexes in crystal structures are linked by O-H…O hydrogen bonds, which created
a three-dimensional hydrogen-bonding networks. The Π-Π stacking interactions are also observed in crystal structures of complex
2. The spectral properties (IR and electronic spectra) of both complexes were also investigated. 相似文献
999.
Shahamirian M Cyrański MK Krygowski TM 《The journal of physical chemistry. A》2011,115(45):12688-12694
Optimization of monosubstituted (X = NO, NO(2), CN, CHO, Me, OMe, OH, NH(2), NHMe, and N(Me)(2)) derivatives of 1,2- and 2,3-naphthoquinone by use of B3LYP with the 6-311+G** basis set applying the GAUSSIAN03 program allowed us to analyze the character of interactions between the substituents and the carbonyl groups. It is shown that only one of two carbonyl groups exhibited substantial substituent effect evidenced by regression of the CO bond length and delocalization index, DI(CO) on the Hammett substituent constants, σ(p), with a very high correlation coefficient, whereas the other one did not depend in any substantial way on σ(p). Dependences of conjugation path built up of bonds between substituent and oxygen atoms of carbonyl groups on σ(p), give more acceptable correlations if the number of bonds in the path is even than in cases when they are odd. 相似文献
1000.
Dariusz Wyrzykowski Iwona Inkielewicz‐Stępniak Justyna Czupryniak Dagmara Jacewicz Tadeusz Ossowski Michal Woźniak Lech Chmurzyński 《无机化学与普通化学杂志》2013,639(10):1795-1799
The reactivity of superoxide free radicals (O2 · –) generated electrochemically towards the oxydiacetate metal complexes, namely [VO(oda)(H2O)2], [Co(oda)(H2O)2] · H2O, and [Ni(oda)(H2O)3] · 1.5H2O (oda = oxydiacetate) was examined by cyclic voltammetry. The measurements were carried out in DMSO solution using a platinum electrode. Based on the height of the anodic peak Ea that corresponds to electrochemical oxidation O2 · – → O2 + e, in the absence and in the presence of the compounds in the mixture, their O2 · – scavenge ability was assessed. The influence of the type of the complex was briefly discussed. H2O2 was used to induce cellular injury in a mouse hippocampal cell line (HT22). The cytoprotection of chemical compounds was tested at the mitochondrial (MTT test) and plasma membrane level (LDH leakage). Dose‐dependent effect (10 and 100 μM of the complex) of investigated compounds was observed. 相似文献