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Nikita A. Kazin Nadezhda S. Demina Roman A. Irgashev Ekaterina F. Zhilina Gennady L. Rusinov 《Tetrahedron》2019,75(33):4686-4696
The effective approaches for regioselective double formylation and acetylation of 5,12-dialkyl-6,7-diaryl-substituted 5,12-dihydroindolo[3,2-a]carbazoles by their treatment with dichloromethyl methyl ether in the presence of SnCl4 or with acetyl chloride in the presence of AlCl3 to afford the 2,9-diformyl or 2,9-diacetyl derivatives, respectively, were developed. Furthermore, new 2,9-bis(2,2-dicyanovinyl) derivatives were synthesized by the Knoevenagel condensation of diformyl-containing substrates with malononitrile, when new 2,9-bis(quinoxaline-2-yl)- and 2,9-bis(benzo[g]quinoxaline-2-yl) derivatives were formed via microwave-promoted oxidation of diacetyl-containing substrates with SeO2 to the corresponding diglyoxals, followed by the reaction of these intermediates with o-phenylendiamine or 2,3-diaminonaphthalene, respectively. The basic optical and electrochemical properties of some 5,12-dihydroindolo[3,2-a]carbazoles were investigated. 相似文献
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The kinetics of dehydrochlorination of 1,1,1-trichloro-2,2-bis(4-nitrophenyl)ethane with sodium nitrite in dipolar aprotic solvents have been studied. Quantum chemical simulation of the process has been performed, and its thermodynamic parameters have been determined. The effects of dissociation and solvation on the rate constant have been considered. The reaction mechanism has been identified as E2H. 相似文献
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P. E. Kazin L. A. Trusov D. D. Zaitsev Yu. D. Tret’yakov 《Russian Journal of Inorganic Chemistry》2009,54(14):2081-2090
This review concerns the synthesis and functional properties of ultrafine particles of M-type hexagonal ferrites prepared
by the most advanced process of oxide glass crystallization. Hexaferrite phase formation during the heat treatment of multicomponent
oxide glasses of various chemical compositions containing boron and/or silicon oxides as glass formers is considered. This
route is useful to prepare assemblies of single-crystal strontium barium hexaferrite particles in the range of average particle
sizes from tens of nanometers to several micrometers. The resulting glass ceramics and magnetic particle assemblies recovered
from them are characterized by high coercive forces, approaching the theoretical limit for such compounds, and high magnetizations,
close to the magnetization value for coarse-grained materials. 相似文献
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The potentialities of a single diffractive lens, a diffractive doublet-achromate, and a diffractive-refractive system for
focusing of X-ray, undulator, and laser radiations are compared. The focusing quality was estimated from the rms radii of
the X-ray scattering pattern and the radii of Airy disks in the diffraction-limited images of a point source. 相似文献
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A. A. Veber O. V. Usovich L. A. Trusov P. E. Kazin V. B. Tsvetkov 《Bulletin of the Lebedev Physics Institute》2012,39(11):305-310
Concentration series of silicate and germanate glasses activated by bismuth are studied. It is shown that luminescence in the IR region is controlled by several active centers related to bismuth. Based on a comparison of spectroscopic characteristics of the studied glasses with the data previously obtained for chloride glass, the observed centers were identified as Bi+, Bi 2 4+ , and Bi 5 3+ in germanate glass and Bi+, Bi 2 4+ in silicate glass. 相似文献
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A. A. Veber A. N. Romanov O. V. Usovich Z. T. Fattakhova E. V. Haula V. N. Korchak L. A. Trusov P. E. Kazin V. B. Sulimov V. B. Tsvetkov 《Applied physics. B, Lasers and optics》2012,108(4):733-736
We observed a high strength near-infrared luminescence in Bi-doped KAlCl4 polycrystalline material. Luminescence dependence on the excitation wavelength and temperature of the sample was studied. Our experimental results allow asserting that the luminescence peaked near 1?μm belongs solely to Bi+ ion which isomorphically substitutes potassium in the crystal. It was also demonstrated that Bi+ luminescence features strongly depend on the local ion surroundings. 相似文献
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Identification of the Chromophore in the Apatite Pigment [Sr10(PO4)6(CuxOH1−x−y)2]: Linear OCuO− Featuring a Resonance Raman Effect,an Extreme Magnetic Anisotropy,and Slow Spin Relaxation 下载免费PDF全文
Prof. Pavel E. Kazin Mikhail A. Zykin Dr. Yan V. Zubavichus Oxana V. Magdysyuk Dr. Robert E. Dinnebier Prof. Dr. Martin Jansen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(1):165-178
A new chromophore has been identified in copper‐doped apatite pigments having the general composition [Sr10(PO4)6(CuxOH1?x?y)2], in which x=0.1, 0.3 and y=0.01–0.42. By using X‐ray absorption spectroscopy, low‐temperature magnetization measurements, and synchrotron X‐ray powder structure refinement, it has been shown that the oxygenated compounds contain simultaneously diamagnetic Cu1+ and paramagnetic Cu3+ with S=1. Cu3+ is located at the same crystallographic position as Cu1+, being linearly coordinated by two oxygen atoms and forming the OCuO? anion. The Raman spectroscopy study of [A10(PO4)6(CuxOH1?x?y)2,], in which A=Ca, Sr, Ba, reveals resonance bands at 651–656 cm?1 assigned to the symmetric stretching vibration (ν1) of OCuO?. The strontium apatite pigment exhibits a strong paramagnetic anisotropy with an unprecedentedly large negative zero‐field splitting parameter (D) of ≈?400 cm?1. The extreme magnetic anisotropy causes slow magnetization relaxation with relaxation times (τ) up to 0.3 s at T=2 K, which relates the compounds to single‐ion magnets. At low temperature, τ is limited by a spin quantum‐tunneling, whereas at high temperature a thermally activated relaxation prevails with Ueff≈48 cm?1. Strong dependence of τ on the paramagnetic center concentration at low temperature suggests that the spin‐spin relaxation dominates in the spin quantum‐tunneling process. The compound is the first example of a d‐metal‐based single‐ion magnet with S=1, the smallest spin at which an energy barrier arises for the spin flipping. 相似文献