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91.
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
92.
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
93.
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
94.
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
95.
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
96.
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
97.
Navzer D. Sachinvala Othman A. Hamed David L. Winsor Walter P. Niemczura Karol Maskos Dharnidhar V. Parikh Wolfgang Glasser Ulli Becker Eugene J. Blanchard Noelie R. Bertoniere 《Journal of polymer science. Part A, Polymer chemistry》1999,37(21):4019-4032
Tri-O-methylcellulose was prepared from partially O-methylated cellulose and its chemical shifts (1H and 13C), and proton coupling constants were assigned using the following NMR methods: (1) One-dimensional 1H and 13C spectra of the title compound were used to assign functional groups and to compare with literature data; (2) double quantum filtered proton–proton correlation spectroscopy (1H, 1H DQF-COSY) was used to assign the chemical shifts of the network of 7 protons in the anhydroglucose portion of the repeat unit; (3) the heteronuclear single-quantum coherence (HSQC) spectrum was used to establish connectivities between the bonded protons and carbons; (4) the heteronuclear multiple-bond correlation (HMBC) spectrum was used to connect the hydrogens of the methyl ethers to their respective sugar carbons; (5) the combination of HSQC and HMBC spectra was used to assign the 13C shifts of the methyl ethers; (6) all spectra were used in combination to verify the assigned chemical shifts; (7) first-order proton coupling constants data (JH,H in Hz) were obtained from the resolution-enhanced proton spectra. The NMR spectra of tri-O-methylcellulose and other cellulose ethers do not resemble the spectra of similarly substituted cellobioses. Although the 1H and 13C shifts and coupling constants of 2,3,6-tri-O-methylcellulose closely resemble those of methyl tetra-O-methyl-β-D -glucoside, there are differences with regard to the chemical shifts and the order of appearances of the resonating nuclei of the methyl ether appendages and the proton at position 4 in the pyranose ring. H4 in tri-O-methylcellulose is deshielded by the acetal system comprising the β-1→4 linkage, and it resonates downfield. H4 in the permethylated glucoside is not as deshielded by the equitorial O-methyl group at C4, and it resonates upfield. The order of appearance of the 1H and 13C resonances in the spectra of the tri-O-methylcellulose repeat unit (from upfield to downfield) are H2 < H3 < H5 < H6a < H3a < H2a < pro R H6B < H4 < pro S H6A ≪ H1 and C6a < C3a < C2a < C6 < C5 < C4 < C2 < C3 ≪ C1, respectively. Close examination of the pyranose ring coupling constants of the repeat unit in tri-O-methylcellulose supports the 4C1 arrangement of the glucopyranose ring. Examination of the proton coupling constants about the C5-C6 bond (J5,6A and J5,6B) in the nuclear Overhauser effect difference spectra revealed that the C6 O-methyl group is predominantly in the gauche gauche conformation about the C5-C6 bond for the polymer in solution. © 1999 John Wiley & Sons, Inc.* J Polym Sci A: Polym Chem 37: 4019–4032, 1999 相似文献
98.
Joanna Korec Karol A. Stasiewicz Katarzyna Garbat Leszek R. Jaroszewicz 《Molecules (Basel, Switzerland)》2021,26(24)
This paper is a continuation of previous work and shows the enhancement of the surface plasmon resonance effect in a tapered optical fiber device. The study investigated liquid crystal cells containing a tapered optical fiber covered with a silver nanolayer, surrounded by a low refractive index liquid crystal in terms of the properties of light propagation in the taper structure. Silver films with a thickness of d = 10 nm were deposited on the tapered waist area. Measurements were performed at room temperature; liquid crystal steering voltage U from 0 to 200 V, with and without any amplitude modulation with a frequency of f = 5 Hz, and the wavelength λ ranged from 550 to 1200 nm. A significant influence of the initial arrangement of liquid crystals molecules on light propagation was observed. Three types of liquid crystal cells—orthogonal, parallel, and twist—were considered. During the measurements, resonant peaks were obtained—the position of which can also be controlled by the type of liquid crystal cells and the steering voltage. Based on the obtained results, the best parameters, such as highest peak’s width reduction, and the highest SNR value were received for twisted cells. In addition, the present work was compared with the previous work and showed the possibility of improving properties of the manufactured probes, and consequently, the surface plasmon resonance effect. In the presented paper, the novelty is mainly focused on the used materials as well as suitable changes in applied technological parameters. In contrast to gold, silver is characterized by different optic and dielectric properties, e.g., refractive index, extension coefficient, and permittivity, which results in changes in the light propagation and the SPR wavelengths. 相似文献
99.
Dr. Manuel Souto Dr. Karol Strutyński Dr. Manuel Melle-Franco Prof. João Rocha 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(48):10912-10935
Electroactive organic molecules have received a lot of attention in the field of electronics because of their fascinating electronic properties, easy functionalization and potential low cost towards their implementation in electronic devices. In recent years, electroactive organic molecules have also emerged as promising building blocks for the design and construction of crystalline porous frameworks such as metal–organic frameworks (MOFs) and covalent-organic frameworks (COFs) for applications in electronics. Such porous materials present certain additional advantages such as, for example, an immense structural and functional versatility, combination of porosity with multiple electronic properties and the possibility of tuning their physical properties by post-synthetic modifications. In this Review, we summarize the main electroactive organic building blocks used in the past few years for the design and construction of functional porous materials (MOFs and COFs) for electronics with special emphasis on their electronic structure and function relationships. The different building blocks have been classified based on the electronic nature and main function of the resulting porous frameworks. The design and synthesis of novel electroactive organic molecules is encouraged towards the construction of functional porous frameworks exhibiting new functions and applications in electronics. 相似文献
100.
Bulko Martin Holý Karol Brandýsová Alžbeta Müllerová Monika Masarik Jozef 《Journal of Radioanalytical and Nuclear Chemistry》2021,328(2):651-657
Journal of Radioanalytical and Nuclear Chemistry - In this study, five different methods for determining the geogenic radon potential are compared in the Mochovce region, Slovakia. Based on these... 相似文献