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61.
Joanna Kulesza Marcin GuzinskiVeronique Hubscher-Bruder Francoise Arnaud-NeuMaria Bocheńska 《Polyhedron》2011,30(1):98-105
The synthesis, characterisation and X-ray crystal structures of p-tert-butyl-calix[4]arene-thioamide L and its complex with lead L-Pb2+ is reported. The cation-binding properties in solution have been assessed by liquid-liquid extraction of the metal picrates from water into dichloromethane and by stability constants determination in acetonitrile using UV-absorption spectrophotometry or potentiometry. The compound was used as active material in Pb-ion-selective membrane electrodes. The characteristics of these electrodes as well as the selectivity coefficients for Pb2+ cation versus many metal ions tested were obtained. Complex formation constants within the electrode membranes were determined using the sandwich membrane method and were compared to those obtained in acetonitrile. The lead concentration in the scrap-lead was determined with the use of electrodes incorporating the ligand studied. 相似文献
62.
Iwona A. Rutkowska Adam Andrearczyk Sylwia Zoladek Monika Goral Kazimierz Darowicki Pawel J. Kulesza 《Journal of Solid State Electrochemistry》2011,15(11-12):2545-2552
A polynuclear electronically/ionically (redox) conducting mixed-valent inorganic material such as nickel(II) hexacyanoferrate(II,III), NiHCF, was considered for potential application as a redox mediator (charge relay) in dye-sensitized solar cell (DSSC). The NiHCF redox reactions were found fast and reversible not only when the system was studied as thin film exposed to an aqueous supporting electrolyte but also as bulk material (pasted powder) in solid state, i.e., in the absence of contact with external liquid electrolyte phase. Usefulness of NiHCF material was diagnosed using conventional electroanalytical approaches, solid-state voltammetric methodology, as well as the dynamic electrochemical impedance spectroscopy technique that permitted monitoring of impedance spectra under potentiodynamic conditions. The material was utilized in a mixed-valent state, i.e., as a mixture of K4NiII[FeII(CN)6] and K3NiII[FeIII(CN)6] in which iron(II) and iron(III) sites were at the 1:1 ratio. Under such conditions, dynamics of electron-hopping between mixed-valent iron sites was maximized. Our DSSC utilized cis–dithiocyanoatobis(4,4??dicarboxylic acid-2,2??bipyridine) ruthenium(II) dye (N3) adsorbed onto TiO2 semiconductor and NiHCF as redox mediator. Although performance of our DSSC was not optimized in terms of the NiHCF film thickness and morphology, as well as lower photocurrents in comparison to those characteristic of the iodine/iodide based DSSC were obtained, our system yielded readily fairly high open-circuit photovoltages on the level of 800?mV. An important issue was that the formal potential of NiHCF was more positive relative to the potential of the iodide/triiodide couple while being still more negative than that equivalent to the ground state of the N3 dye. Thus, NiHCF mediator was able to regenerate the dye. 相似文献
63.
Structural and photochemical properties of organosilver reactive intermediates MeAg2(+) and PhAg2(+)
Brunet C Antoine R Broyer M Dugourd P Kulesza A Petersen J Röhr MI Mitrić R Bonačić-Koutecký V O'Hair RA 《The journal of physical chemistry. A》2011,115(33):9120-9127
Although there is growing interest in silver promoted carbon-carbon bond formation, a key challenge in developing robust and reliable organosilver reagents is that thermal and photochemical decomposition reactions can compete with the desired coupling reaction. These undesirable reactions have been poorly understood due to complications arising from factors such as solvent effects and aggregation. Here the unimolecular decomposition reactions of organosilver cations, RAg(2)(+), where R = methyl (Me) and phenyl (Ph), are examined in the gas phase using a combination of mass spectrometry based experiments and theoretical calculations to explore differences between thermal and photochemical decompositions. Under collision-induced dissociation conditions, which mimic thermal decomposition, both PhAg(2)(+) and MeAg(2)(+) fragment via formation of Ag(+). The new ionic products, RAg(+?) and Ag(2)(+?), which arise via bond homolysis, are observed when RAg(2)(+) is subject to photolysis using a UV-vis tunable laser OPO. Furthermore, comparisons between the theoretical and experimental UV-vis spectra allow us to unambiguously determine the most stable structures of PhAg(2)(+) and MeAg(2)(+) and to identify the central role of the silver part in the optical absorption of these species. The new photoproducts result from fragmentation in electronic excited states. In particular, potential energy surface calculations together with the fragment charges highlight the role of triplet states in these new fragmentation schemes. 相似文献
64.
Dr. Joydeb Goura Dr. Bassem S. Bassil Dr. Jasleen K. Bindra Dr. Iwona A. Rutkowska Prof. Pawel J. Kulesza Prof. Naresh S. Dalal Prof. Ulrich Kortz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(68):15821-15824
The 48-FeIII-containing 96-tungsto-16-phosphate, [FeIII48(OH)76(H2O)16(HP2W12O48)8]36− ( Fe48 ), has been synthesized and structurally characterized. This polyanion comprises eight equivalent {FeIII6P2W12} units that are linked in an end-on fashion forming a macrocyclic assembly that contains more iron centers than any other polyoxometalate (POM) known to date. The novel Fe48 was synthesized by a simple one-pot reaction of an {Fe22} coordination complex with the hexalacunary {P2W12} POM precursor in water. The title polyanion was characterized by single-crystal XRD, FTIR, TGA, magnetic and electrochemical studies. 相似文献
65.
Marta Sosnowska Monika Goral-Kurbiel Magdalena Skunik-Nuckowska Rafal Jurczakowski Pawel J. Kulesza 《Journal of Solid State Electrochemistry》2013,17(6):1631-1640
Preparation and electrochemical behavior of new hybrid materials composed of multi-walled carbon nanotubes (CNTs) that were derivatized with poly(diallyldimethylammonium) chloride and modified with vanadium-mixed addenda Dawson-type heteropolytungstate, [P2W17VO62]8?, is described here. These nanostructured composite systems exhibited fast dynamics of charge propagation. They were characterized by the transport (effectively diffusional) kinetic parameter of approximately 8?×?10?8 cm?2 s?1/2 and the specific capacitance parameter of 82 F g?1 (at the charging/discharging current of 200 mA g?1). The latter parameter for bare CNTs was found to be only 50 F g?1 under analogous conditions. These observations were based on the results of galvanostatic charging–discharging, cyclic voltammetric, and AC impedance spectroscopic measurements. The improved capacitance properties were attributed to the systems’ pseudocapacitive features originating from the fast redox transitions of the [P2W17VO62]8? polyanions. In addition to the fast redox conduction, the proposed organic–inorganic hybrid materials exhibited interesting electrocatalytic activity toward reduction of bromate in the broad concentration range (sensitivity, 0.24 mA cm?2 mmol?1 dm3). 相似文献
66.
B. Layla Mehdi Iwona A. Rutkowska Pawel J. Kulesza James A. Cox 《Journal of Solid State Electrochemistry》2013,17(6):1581-1590
Modification of electrodes with nanometer-scale organically modified silica films with pore diameters controlled at 10- and 50-nm is described. An oxidation catalyst, mixed-valence ruthenium oxide with cyano cross-links or gold nanoparticles protected by dirhodium-substituted phosphomolybdate (AuNP-Rh2PMo11), was immobilized in the pores. These systems comprise size-exclusion films at which the biological compounds, phosphatidylcholine and cardiolipin, were electrocatalytically oxidized without interference from surface-active concomitants such as bovine serum albumin. Ten-nanometer pores were obtained by adding generation-4 poly(amidoamine) dendrimer, G4-PAMAM, to a (CH3)3SiOCH3 sol. Fifty-nanometer pores were obtained by modifying a glassy carbon electrode (GC) with a sub-monolayer film of aminopropyltriethoxylsilane, attaching 50-nm diameter poly(styrene sulfonate), PSS, spheres to the protonated amine, transferring this electrode to a (CH3)3SiOCH3 sol, and electrochemically generating hydronium at uncoated GC sites, which catalyzed ormosil growth around the PSS. Voltammetry of Fe(CN)6 3? and Ru(NH3)6 3+ demonstrated the absence of residual charge after removal of the templating agents. With the 50-nm system, the pore structure was sufficiently defined to use layer-by-layer electrostatic assembly of AuNP-Rh2PMo11 therein. Flow injection amperometry of phosphatidylcholine and cardiolipin demonstrated analytical utility of these electrodes. 相似文献
67.
It is widely known that a developing shaft crack manifests itself in the appearance of nonlinear effects resulting in higher harmonics in a vibration spectrum. However, such symptoms are characteristic not only for developing shaft cracks but also for other malfunctions such as a shaft bow, a coupling misalignment, etc. That is why novel shaft crack detection methods introduce a specially designed diagnostic force applied to the shaft in order to amplify the particular symptoms of the crack. Most often a simple harmonic force is used for such purposes, yet the results may not be reliable. 相似文献
68.
Monika Góral-Kurbiel Alicja Drelinkiewicz Robert Kosydar Jacek Gurgul Beata Dembińska Paweł J. Kulesza 《Journal of Solid State Electrochemistry》2014,18(3):639-653
Present studies concentrated on the preparation, characterization, and electroactivity of palladium–polypyrrole (Pd/PPY) catalysts for oxygen reduction reaction. In particular, the effect of Nafion ionomer on their electroactivity was evaluated. In all catalysts prepared by “water-in-oil” microemulsion method, the Pd nanoparticles of ca. 7 nm in size appeared regardless of the Pd content (ranging from 2 to 20 wt.%). For comparison, carbon black-supported (Vulcan XC-72) catalyst (20 wt.% Pd) was also synthesized. Coating of the Pd/PPY samples with Nafion ionomer reduced their surface area and porosity. Chemical interaction due to Nafion acid functionalities affected the N-state of pyrrole as well as electron state of Pd in the Pd/PPY catalysts. As a result, the contribution of more oxidized palladium (Pdδ+) increased. These interactions played an essential role in the electroactivity of Pd/PPY for oxygen reduction reaction. The increased amount of Nafion relative to that of PPY reduced limiting current density whereas the half-wave potential shifted to a more positive value and the fraction of hydrogen peroxide remarkably decreased. 相似文献
69.
70.