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31.
E. V. Tretyakov S. V. Fokin G. V. Romanenko V. N. Ikorskii A. V. Podoplelov V. I. Ovcharenko 《Russian Chemical Bulletin》2006,55(1):66-73
An efficient procedure was developed for the synthesis of alkyltetrazolyl-substituted nitronyl nitroxides (L
1 and L
2). These compounds were used to prepare the first alkyltetrazolyl-substituted imino nitroxides (L
3 and L
4). The molecular structures of L
3 and L
4 were confirmed by X-ray diffraction. Investigation of the products prepared by the reaction of copper(II) bis(hexafluoroacetylacetonate), Cu(hfac)2, with nitroxides made it possible to divide ligands L
1—L
4 into two groups. The reactions of spin-labeled tetrazoles L
1—L
3 with Cu(hfac)2 afford the heterospin complexes Cu(hfac)2L2, whereas L
4 serves as a bidentate ligand in the Cu(hfac)2
L
4 complex. In the solid Cu(hfac)2L2 complexes, antiferromagnetic exchange interactions between the unpaired electrons of the nitroxide fragments of the adjacent
molecules prevail, due to which μeff decreases with decreasing temperature, and the spins of nitroxides are completely compensated at 5–10 K. The Cu(hfac)2
L
4 complex displays strong intramolecular ferromagnetic coupling, due to which μeff at room temperature is close to 2.9 μB.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 64–70, January, 2006. 相似文献
32.
Anastasiia M. Mishura Anna S. Sklyarova Dmitriy I. Sharapa Igor’ A. Levandovsky Michael Serafin Andrey A. Fokin Vladimir N. Rodionov 《Central European Journal of Chemistry》2013,11(12):2144-2150
The rearrangement of easily accessible Cookson’s diketone with chlorosulfonic acid in chloroform followed by the acidic hydrolysis gave 6-chloro-7-hydroxy-dichloropentacyclo[6.3.0.02,6.03,10.05,9]undecane-4-one, whose syn-stereochemistry was assigned through the X-ray crystal structure analysis. This key structure was used for the stereoselective synthesis of the D 3-trishomocubane derivatives as well as for the preparation of potential drugs bearing hydroxy- and amino-functional groups. A new multigram preparative synthesis of D 3-trishomocubane was developed. 相似文献
33.
Chiavarino B Crestoni ME Fokin AA Fornarini S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(13):2916-2921
The protonation of cyclopropane by gaseous Br?nsted acids of varying strength in radiolytic experiments at atmospheric pressure leads to two distinct C3H7- isomers that have been sampled by their reaction with benzene. The neutral end products, nC3H7-C6H5 and iC3H7-C6H5, arise from the electrophilic aromatic substitution reaction with the cC3H7+ and iC3H7+ ions, respectively. Their relative abundance was studied as a function of pressure, temperature, and the presence of additives in the gaseous systems; the results indicate a large extent of isomerization to the thermodynamically favored iC3H7+ from the protonation by strong acids. The presence of a kinetic barrier prevents any thermal isomerization from taking place in the time frame of 10(-8) s. In the peculiar case in which protonated benzene is the Br?nsted acid, C3H7+ ions are formed in the presence of neutral benzene within the same ion - molecule complex. The ensuing reaction shows that cC3H7+ ions are formed exclusively and react in the 10(-10) s(-1) estimated lifetime of the complex. Still, such cC3H7+ ions undergo complete randomization of their hydrogen atoms; this points to a low kinetic barrier for the process. Agreement is found between the reported experimental results and updated computations of the relevant species in the C3H7+ potential energy surface. 相似文献
34.
K. V. Komarov N. D. Chkanikov S. V. Sereda M. Yu. Antipin Yu. T. Struchkov A. F. Kolomiets A. V. Fokin 《Russian Chemical Bulletin》1988,37(8):1717-1719
Conclusions The reactions of -naphthylamine with 2,2-bis(trifluororaethyl)-1,1-dicyanoethylene leads to the formation of 2-amino-4,4-bis(trifluoromethyl)-3-cyano-1,4-dihydrobenzo[h]quinoline. The structure of this product was established by x-ray diffraction structural analysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1917–1920, August, 1988. 相似文献
35.
Methyl trifluoropiruvate in trifluoroacetic acid at 20 °C rapidly C-hydroxyalkylates various phenols at thepara-positions to afford the corresponding esters ofpara-hydroxy substituted -trifluoromethylmandelic acids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 528–530, March, 1995.The present study was carried out with the financial support of the Russian Foundation for Basic Research (Project code 93-03-22696). 相似文献
36.
37.
I. G. Fokin V. I. Savchenko V. S. Arutyunov 《Russian Journal of Physical Chemistry B, Focus on Physics》2014,8(2):148-151
Experimental results on the partial oxidation of methane-ethane and C1–C4 alkane gas mixtures are reported. The effect of the parameters of the process on the methanol-to-carbon monoxide ratio in the reaction products is examined and the possibility to control this ratio, important for the subsequent carbonylation of the products, is demonstrated. 相似文献
38.
Sergey L. Veber Matvey V. Fedin Sergey V. Fokin Renad Z. Sagdeev Victor I. Ovcharenko Elena G. Bagryanskaya 《Applied magnetic resonance》2010,37(1-4):693-701
We report the X-band (9 GHz) electron paramagnetic resonance (EPR) study of series of bis(o-semiquinonato)copper(II) complexes with different ligands. It was found previously, that exchange interactions in spin triads of these compounds are very sensitive to the structure of the ligand coordinated to the central copper(II) ion. Ligand moderates the copper–radical and radical–radical exchange interactions and strongly changes the magnetic properties of the compound. Depending on a ligand, ferromagnetic or antiferromagnetic character of exchange dominates in the system. The EPR study of these complexes allowed us to obtain information on zero-field splitting parameters and their distributions in the studied compounds. The EPR results compliment previously obtained spectroscopic data on these compounds and suggest the pronounced plasticity of the clusters manifested in the broad distributions of their rhombicity parameters. 相似文献
39.
S. V. Fokin E. T. Kostina E. V. Tret’yakov G. V. Romanenko A. S. Bogomyakov R. Z. Sagdeev V. I. Ovcharenko 《Russian Chemical Bulletin》2013,62(3):661-671
The synthesis, structure, and magnetic properties of the products of the reaction for Cu(hfac)2 (hfac is hexafluoroacetylacetonate) with spin-labeled nitronyl nitroxides 4,4,5,5-tetramethyl-2-(1-R-1H-pyrazol-5-yl)-3-imidazoline-1-oxyl 3-oxides L5/R (R = Me, Et, Pr, Bu), viz., binuclear complex [Cu(hfac)2L5/Me]2 and chain polymer complexes [Cu(hfac)2L5/R]n, are described. The polymer heterospin chains are built according to “head-to-head” (R = Me, Et, Pr, Bu) and “head-to-tail” (R = Pr, Bu) motifs. Compound [Cu(hfac)2L5/Me]2 is characterized by the ability to reveal the reversible effect of thermally induced spin transition at a temperature about 75 K (without hysteresis). In the set of heterospin CuII compounds with spin-labeled pyrazoles, this is the earlier unknown example of a molecular complex exhibiting a similar magnetic anomaly. 相似文献
40.
Fokin V. N. Son V. B. Fokina E. E. Tarasov B. P. 《Russian Journal of Applied Chemistry》2020,93(12):1831-1836
Russian Journal of Applied Chemistry - The reactions of intermetallic compounds ACo3 (A = Ce, Y) with hydrogen and ammonia at 20–450°C were studied. The composition of the products and... 相似文献