排序方式: 共有17条查询结果,搜索用时 15 毫秒
1.
M. M. Iskakova I. M. Biktagirov L. Kh. Faizullina Sh. M. Salikhov M. G. Safarov F. A. Valeev 《Russian Journal of Organic Chemistry》2014,50(1):105-109
The Dieckmann condensation of 3,4-bis(methoxycarbonylmethyl) levoglucosenone derivative afforded two regioisomeric 9,11-dioxatricyclo[6.2.1.02,6]undecane derivatives at a ratio of 5: 3. The products can be used in the synthesis of iridoids. 相似文献
2.
I. M. Biktagirov L. Kh. Faizullina Sh. M. Salikhov M. G. Safarov F. A. Valeev 《Russian Journal of Organic Chemistry》2014,50(9):1317-1322
4,4-Dimethyl-3-nitro-10,11-dioxatricyclo[6.2.1.02,6]undec-5-en-7-one possessing a bicyclic iridoid skeleton was synthesized in two steps from isolevoglucosenone which was obtained in turn from levoglucosenone through 4-benzyloxy-2-tosyloxy derivative. 相似文献
3.
M. R. Gafurov T. B. Biktagirov G. V. Mamin D. V. Shurtakova E. S. Klimashina V. I. Putlyaev S. B. Orlinskii 《Physics of the Solid State》2016,58(3):469-474
The effect of codoping of hydroxyapatite (HAP) nanocrystals with average sizes of 35 ± 15 nm during “wet” synthesis by CO32? carbonate anions and Mn2+ cations on relaxation characteristics (for the times of electron spin–spin relaxation) of the NO32? nitrate radical anion has been studied. By the example of HAP, it has been demonstrated that the electron paramagnetic resonance (EPR) is an efficient method for studying anion–cation (co)doping of nanoscale particles. It has been shown experimentally and by quantummechanical calculations that simultaneous introduction of several ions can be energetically more favorable than their separate inclusion. Possible codoping models have been proposed, and their energy parameters have been calculated. 相似文献
4.
Marat Gafurov Timur Biktagirov Georgy Mamin Sergei Orlinskii 《Applied magnetic resonance》2014,45(11):1189-1203
Incorporation of the nitrogen-containing impurities in hydroxyapatite (HAp) powders with the sizes of the crystallites of (20–50) nm was studied using first-principles modeling combined with the multi-frequency (9 and 94 GHz) electron paramagnetic resonance (EPR) methods. It is shown that the observed EPR spectra are undoubtedly due to the presence of the bulk radiation-induced NO3 2? radicals. This conclusion is based on spin-polarized density functional theory calculations of spectroscopic parameters within gauge-including projector augmented wave framework followed by the exact comparison of the simulated EPR and electron–nuclear double resonance spectra with the experimental findings. In addition, a comprehensive analysis of the simulated properties allows us to suggest that the paramagnetic centers preferably occupy PO4 3? sites in the HAp structure. 相似文献
5.
Yavkin BV Mamin GV Orlinskii SB Gafurov MR Salakhov MKh Biktagirov TB Klimashina ES Putlayev VI Tretyakov YD Silkin NI 《Physical chemistry chemical physics : PCCP》2012,14(7):2246-2249
W-band pulsed EPR and ENDOR investigations of X-ray irradiated nanoparticles of synthetic hydroxyapatite Ca(9)Pb(PO(4))(6)(OH)(2) are performed. It is shown that in the investigated species lead ions probably replace the Ca(1) position in the hydroxyapatite structure. 相似文献
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7.
M. Gafurov T. Biktagirov B. Yavkin G. Mamin Y. Filippov E. Klimashina V. Putlayev S. Orlinskii 《JETP Letters》2014,99(4):196-203
Synthesized by the wet chemical precipitation technique, hydroxyapatite (HAp) powders with the sizes of the crystallites of 20–50 nm and 1 μm were analyzed by different analytical methods. By means of electron paramagnetic resonance (EPR) it is shown that during the synthesis process nitrate anions from the reagents (byproducts) could incorporate into the HAp structure. The relaxation times and EPR parameters of the stable axially symmetric NO 3 2? paramagnetic centers detected after X-ray irradiation are measured with high accuracy. Analyses of high-frequency (95 GHz) electron-nuclear double resonance spectra from 1H and 31P nuclei and ab initio density functional theory calculations allow suggesting that the paramagnetic centers and nitrate anions as the precursors of NO 3 2? radicals preferably occupy PO 4 3? site in the HAp structure. 相似文献
8.
In an EPR study of the catalytic system TiCl4 + Al(i-C4H9)3 in toluene and isopentane in TiCl4/oligopiperylene + Al(i-C4H9)3 in toluene, we have observed a dependence of the linewidth of the hyperfine structure on the mobility of the complex in solution.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 174–177, March–April, 2007. 相似文献
9.
Oxidation with CrO<Subscript>3</Subscript>·2Py of levoglucosenone and 1,3-dienes Diels-Alder adducts
I. M. Biktagirov L. Kh. Faizullina Sh. M. Salikhov F. Z. Galin M. G. Safarov F. A. Valeev 《Russian Journal of Organic Chemistry》2016,52(5):711-720
Diels-Alder adducts of levoglucosenone with 1,3-butadiene, piperylene, and isoprene, and also some of their derivatives undergo allylic oxidation with CrО3·2Py only in the case when the effect of a keto group or of another electron-acceptor group in the γ-position with respect to the double bond is removed. 相似文献
10.
V. V. Biktagirov O. V. Mikhailov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(7):1177-1179
Toluene solutions of titanium tetrachloride-triisobutyl aluminium varying in molar ratio from 1: 3 to 1: 30 are studied by electron paramagnetic resonance spectroscopy at 77 K. It is shown that the stepwise reduction of Ti(IV) to Ti(III) occurs under these conditions, resulting in the formation of TI 2 7+ and TI 2 6+ heterovalent compounds. A feasible mechanism for the interaction between TiCl4 and Al(i-Bu)3 is proposed. 相似文献