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131.
Artur Sikorski Karol Krzymiski Antoni Konitz Jerzy Baejowski 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(4):o227-o230
The title compounds, C21H14Cl2NO2+·CF3O3S−, (I), and C20H11Cl2NO2, (II), form triclinic crystals. Adjacent cations of (I) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Together with the CF3SO3− anions, the antiparallel‐oriented cations of (I) form layers in which the molecules are linked via a network of C—H·O and π–π interactions (between the benzene rings). These layers, in turn, are linked via a network of multidirectional π–π interactions between the acridine rings, and the whole lattice is stabilized by electrostatic interactions between ions. Adjacent molecules of (II) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Parallel‐oriented molecules are arranged in chains stabilized via C—H·Cl interactions. These chains are oriented either parallel or antiparallel and are stabilized, in the latter case, via multidirectional π–π interactions and more generally via dispersive interactions. Acridine and independent benzene moieties lie parallel in the lattices of (I) and (II), and are mutually oriented at an angle of 33.4 (2)° in (I) and 9.3 (2)° in (II). 相似文献
132.
Seismic isolation has been recognised to be a very effective way of protecting structures from damage during earthquakes. It allows us to extend the natural period of the structure and therefore avoid resonance with the ground motion. Moreover, by increasing damping in the isolation devices, more energy can be dissipated and thus the structural response can be further reduced. The aim of this paper is to show the results of the study focused on verification of the applicability of the innovative method of seismic isolation by installing bearings made of a polymer mass, which is an especially designed flexible elastoplastic two-component grout based on polyurethane resin. In the study, a model structure was tested experimentally on a shaking table under earthquake excitation. First, the structure was fixed directly to the table and its response was recorded. Then, the response of the structure with polymer bearings installed at its base was observed and both responses were compared. The results of the study show that equipping the structure with the polymer bearings can considerably reduce the structural response under earthquake excitation. The innovative method considered in the study has been verified to be an effective seismic isolation technique. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
133.
According to popular belief, oxygen and water are the natural enemies of organometallic reactions and therefore must be excluded rigorously from the reaction vessel. This belief is founded in the case of the highly reactive nucleophilic metal alkylidene complexes that were used in early catalytic olefin metathesis. However, owing to the high stability of the ruthenium carbene complexes introduced by Grubbs, metathesis in water has become reality. 相似文献
134.
Stefan Czarnocki Louis Monsigny Micha Sienkiewicz Anna Kajetanowicz Karol Grela 《Molecules (Basel, Switzerland)》2021,26(17)
A modular and flexible strategy towards the synthesis of N-heterocyclic carbene (NHC) ligands bearing Brønsted base tags has been proposed and then adopted in the preparation of two tagged NHC ligands bearing rests of isonicotinic and 4-(dimethylamino)benzoic acids. Such tagged NHC ligands represent an attractive starting point for the synthesis of olefin metathesis ruthenium catalysts tagged in non-dissociating ligands. The influence of the Brønsted basic tags on the activity of such obtained olefin metathesis catalysts has been studied. 相似文献
135.
We propose a method for the modification of surfaces of microchannels in chips fabricated in polycarbonate (PC) that makes the devices resistant to a range of organic solvents. Coating of PC with branched polyethyleneimine (BPEI) with the use of trimethylpropane triglycidyl ether (TTE) as a linker renders the devices resistant to toluene, benzene, acetonitrile, tetrahydrofuran, dioxane and ethylene dichloride. The optimized procedure of modification allows for continuous operation of the chips for several hours without dissolution of PC. Additional modification with the use of Krytox? allows for the use of Fluorinert (FC-40) as the continuous phase and for generation and handling of droplets of organic solvents that are miscible with water. 相似文献
136.
KI Wysokiński 《J Phys Condens Matter》2012,24(33):335303
The thermoelectric transport in the system composed of a quantum dot in contact with superconducting, ferromagnetic and normal metal electrodes has been studied. Such a system can support pure spin current in the normal electrode. In the limit of a large superconducting gap and weak coupling between the dot and the electrodes we investigate the sub-gap charge and spin transport via Andreev mechanism using the standard master equation technique, which is known to be valid in the sequential tunnelling regime. The Zeeman splitting of the dot level induces pure spin current in the ferromagnetic electrode under an appropriate bias. This opens a novel possibility to switch the spin current between two electrodes by electric means. The calculated spin and charge thermopower coefficients attain very large values, of the order of a few hundreds μV K(-1), and show similar dependences on the position of the on-dot energy level and temperature. 相似文献
137.
Karol Ciepluch Nadia Katir Abdelkrim El Kadib Monika Weber Anne-Marie Caminade Mostapha Bousmina Jean Pierre Majoral Maria Bryszewska 《Journal of luminescence》2012,132(6):1553-1563
This work deals with photo-physical and structural interactions between viologen phosphorus dendrimers and human serum albumin (HSA). Viologens are derivatives of 4,4′-bipyridinium salts. Aiming to rationalize the parameters governing such interactions eight types of these polycationic dendrimers in which the generation, the number of charges, the nature of the core and of the terminal groups vary from one to another, were designed and used. The influence of viologen-based dendrimers' on human serum albumin has been investigated. The photo-physical interactions of the two systems have been monitored by fluorescence quenching of free l-tryptophan and of HSA tryptophan residue. Additionally, using circular dichroism (CD) the effect of dendrimers on the secondary structure of albumin was measured. The obtained results show that viologen dendrimers interact with human serum albumin quenching its fluorescence either by collisional (dynamic) way or by forming complexes in a ground state (static quenching). In some cases the quenching is accompanied by changes of the secondary structure of HSA. 相似文献
138.
K Bhaskaran-Nair J Brabec E Aprà HJ van Dam J Pittner K Kowalski 《The Journal of chemical physics》2012,137(9):094112
In this paper we discuss the performance of the non-iterative state-specific multireference coupled cluster (SS-MRCC) methods accounting for the effect of triply excited cluster amplitudes. The corrections to the Brillouin-Wigner and Mukherjee's MRCC models based on the manifold of singly and doubly excited cluster amplitudes (BW-MRCCSD and Mk-MRCCSD, respectively) are tested and compared with exact full configuration interaction results for small systems (H(2)O, N(2), and Be(3)). For the larger systems (naphthyne isomers) the BW-MRCC and Mk-MRCC methods with iterative singles, doubles, and non-iterative triples (BW-MRCCSD(T) and Mk-MRCCSD(T)) are compared against the results obtained with single reference coupled cluster methods. We also report on the parallel performance of the non-iterative implementations based on the use of processor groups. 相似文献
139.
Aleksandra Tyl El?bieta Che?mecka Magdalena Jab?ońska Maria Nowak Joachim Kusz Karol Pasterny Roman Wrzalik 《Structural chemistry》2012,23(2):325-332
The X-ray structure, synthesis, theoretical calculation and IR spectra of 1-naphthaleneacrylic acid are reported. The titled
compound crystallizes in the monoclinic C 2/c space group with unit cell parameters: a = 14.556(3), b = 5.1332(10), c = 26.832(5) ?, β = 97.02(3)°, V = 1989.8(7) ?3, Z = 8 and form typical centrosymmetric hydrogen-bonded dimers. Theoretical calculations of 1-naphthylacrylic acid isolated
molecule and hydrogen-bonded dimer have been carried out using density functional theory at the B3LYP level. For optimized
structures the vibrational spectra have been then calculated and compared with experimental IR spectrum. The assignment and
characterization of theoretical vibrational spectra were based on the potential energy distribution analysis. This comparison
has shown that the theoretical spectrum for the dimer structure is in good agreement with the experimental one. Structural
comparisons with naphthalene, and with some substituted 2-propenoic acids have shown influence of the substituent on conformation
of the naphthalene ring or 2-propenoic moiety. 相似文献
140.
We discuss the role of tangential stabilization in a curvature driven flow of planar curves. The governing system of nonlinear parabolic equations includes a nontrivial tangential velocity functional yielding a uniform redistribution of grid points along the evolving family of curves preventing numerically computed curves from forming various instabilities. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献