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排序方式: 共有180条查询结果,搜索用时 31 毫秒
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V. M. Lisitsyn V. I. Korepanov E. V. Borovko Yu. A. Dobrozhanskii V. A. Presnov V. A. Chaldyshev V. N. Chernyshov V. V. Gorlach V. V. Svishchenko G. V. Maier I. N. Anokhina V. E. Egorushkin A. I. Nazhalov V. F. Nyavro V. A. Popov N. I. Fedyainova V. P. Fadin V. N. Shapovalov G. V. Nikolaev I. I. Klykov V. N. Gorshenkov V. I. Popov 《Russian Physics Journal》1975,18(11):1639-1643
65.
Dr. Ilia Kochetygov Jocelyn Roth Dr. Jordi Espín Sophia Pache Dr. Anita Justin Till Schertenleib Dr. Nazanin Taheri Dr. Dmitry Chernyshov Prof. Wendy L. Queen 《Angewandte Chemie (International ed. in English)》2023,62(16):e202215595
The design of metal–organic frameworks (MOFs) having large pore sizes and volumes often requires the use of complex organic ligands, currently synthesized using costly and time-consuming palladium-catalyzed coupling chemistry. Thus, in the present work, a new strategy for ligand design is reported, where piperazine and dihydrophenazine units are used as substitutes for benzene rings, which are the basic building block of most MOF ligands. This chemistry, which is based on simple, nucleophilic aromatic substitution (SNAr) reactions, is used for the transition metal catalyst-free construction of 21 new, carboxylate-based ligands with varying sizes, shapes, and denticity and 15 linear di- and tetra-nitriles. Moreover, to demonstrate the utility of the ligands as building blocks, 16 new structurally diverse MOFs having surface areas up to 3100 m2 g−1 were also synthesized. 相似文献
66.
Screen-printed electrodes modified with carbon paste that consisted of graphite powder dispersed in ionic liquids (IL) were used for the electrochemical determination of dopamine, adrenaline and dobutamine in aqueous solutions by means of cyclic voltammetry. The IL plays a dual role in modifying compositions, acting both as a binder and chemical modifier (ion-exchanger); ion-exchange analyte pre-concentration increases analytical signal and improves the sensitivity. Calibration graphs are linear in concentration range 3.9 × 10−6 to 1.0 × 10−4 M (dopamine), 2.9 × 10−7 to 1.0 × 10−4 M (adrenaline) and 1.7 × 10−7 to 1.0 × 10−4 M (dobutamine); detection limits are (1.2 ± 0.1) × 10−6, (1.3 ± 0.1) × 10−7 and (5.3 ± 0.1) × 10−8 M, respectively. Using an additive of Co (III) tetrakis-(tert-butyl)-phthalocyanine leads to the increase of signal and lowering detection limit. Some practical advises concerning both the sensor design and selectivity of catecholamine determination are provided. 相似文献
67.
Extended structure design with simple molybdenum oxide building blocks and urea as a directing agent
Veen SJ Roy S Filinchuk Y Chernyshov D Petukhov AV Versluijs-Helder M Broersma A Soulimani F Visser T Kegel WK 《Inorganic chemistry》2008,47(15):6863-6866
We report here a simple one-pot directed synthesis of an oxomolybdate urea composite in which elementary molybdenum oxide building blocks are linked together with the aid of urea. This type of directed material design resulted in large rod-like crystals of an inorganic-organic hybrid extended structure of {MoO 3(NH 2-CO-NH 2)} infinity consisting of right- and left-handed helical units. In the crystal structure urea acts both as a glue that links the inorganic molybdenum units into a helix and as a supramolecular linker for the stabilization of the crystal structure as a whole. This type of molecular topology resulted in an unexpectedly high thermal stability. 相似文献
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A. A. Veligzhanin Ya. V. Zubavichus N. Yu. Kozitsyna V. Yu. Murzin E. V. Khramov A. A. Chernyshov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2013,7(3):422-433
The formation of metal or metal-oxide nanoparticles from four different precursor systems, including palladium(II) acetate, zinc(II) acetate, their 1: 1 mechanical mixture and the palladium-zinc bimetallic acetate complex PdZn(OCOMe)4(H2O), upon heating in a He + 5% H2 atmosphere is studied using the X-ray diffraction and EXAFS (Extended X-ray absorption fine structure) techniques in the in situ mode. X-ray diffraction is primarily used to monitor changes in the phase composition of the samples. At specific moments when qualitative changes in the composition occur, EXAFS spectra at the K-edges of Pd and Zn are also measured. Using a combination of these two techniques, a detailed sequence of the phase transformations in each of the four precursor systems is revealed. It is found that the bimetallic acetate complex and the mixture of two monometallic acetates undergo chemical reduction to form zerovalent palladium under milder conditions than zinc acetate. However, the formation of a PdZn alloy from the mixture of metal acetates proceeds with a significant diffusion barrier. 相似文献
69.
Krzton-Maziopa A Pomjakushina E Pomjakushin V Sheptyakov D Chernyshov D Svitlyk V Conder K 《J Phys Condens Matter》2011,23(40):402201
We report on the synthesis of single crystals of BaFe(2)Se(3) and study their crystal and magnetic structures by means of synchrotron single-crystal x-ray and neutron powder diffraction. The crystal structure has orthorhombic symmetry and consists of double chains of FeSe(4) edge connected tetrahedra intercalated with barium. Below 240 K, long range spin-block checkerboard antiferromagnetic order is developed. The magnetic structure is similar to one observed in A(0.8)Fe(1.6)Se(2) (A = K, Rb or Cs) superconductors. The crystals exhibit a transition to the diamagnetic state with an onset transition temperature of T(c) ~ 11 K. Though we observe FeSe as an impurity phase (<0.8% mass fraction) it is not likely that the diamagnetism is attributable to the FeSe superconductor, which has T(c) ≈ 8.5 K. 相似文献
70.
Svitlyk V Chernyshov D Pomjakushina E Krzton-Maziopa A Conder K Pomjakushin V Dmitriev V 《Inorganic chemistry》2011,50(21):10703-10708
Temperature-dependent synchrotron powder diffraction on Cs(0.83)(Fe(0.86)Se)(2) revealed first-order I4/m to I4/mmm structural transformation around 216 °C associated with a disorder of the Fe vacancies. Irreversibility observed during the transition is likely associated with a mobility of the intercalated alkali atoms. Pressure-dependent synchrotron powder diffraction on Cs(0.83)(Fe(1-y)Se)(2), Rb(0.85)(Fe(1-y)Se)(2), and K(0.8)(Fe(1-y)Se)(2) (y ~ 0.14) indicated that the I4/m superstructure reflections are present up to pressures of 120 kbar. This may indicate that the ordering of the Fe vacancies is present in both superconducting and nonsuperconductive states. 相似文献