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51.
Russian Journal of General Chemistry - Investigation of the structure and conformational properties of ammonia borane molecule in the cavity of C60, C12B24N24, B36N24, C70, B41N29, C80, C14B33N33,... 相似文献
52.
Cherkashina K. D. Pochivalov A. S. Shakirova F. M. Shishov A. Yu. Bulatov A. V. 《Journal of Analytical Chemistry》2022,77(3):334-341
Journal of Analytical Chemistry - A method of liquid–liquid microextraction is proposed for the extraction and preconcentration of tetracycline antibiotics from milk. It involves the... 相似文献
53.
G. A. Berezovskii D. P. Pishchur O. G. Shakirova L. G. Lavrenova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(11):1827-1831
The temperature dependences of the heat capacities at 106–330 K of the monoligand Fe(NH2trz)3I2 (I) and mixed-ligand Fe(Htrz)0.3(NH2trz)2.7SiF6 · H2O (II) complexes (Htrz is 1,2,4-triazole, and NH2trz is 4-amino-1,2,4-triazole) were studied by adiabatic vacuum calorimetry. The 1A1 ⇔ 5T2 spin transition was observed in these compounds. The thermodynamic parameters of phase transitions in I and II were determined. 相似文献
54.
Maria G. Babashkina Elmira R. Shakirova Dr. Damir A. Safin Felix D. Sokolov Axel Klein Łukasz Szyrwiel Maria Kubiak Henryk Kozlowski Dmitriy B. Krivolapov 《无机化学与普通化学杂志》2010,636(15):2626-2632
Reaction of O,O′‐diisopropylthiophosphoric acid isothiocyanate (iPrO)2P(S)NCS with 1,10‐diaza‐18‐crown‐6, 1,7‐diaza‐18‐crown‐6, or 1,7‐diaza‐15‐crown‐5 leads to the N‐thiophosphorylated bis‐thioureas N,N′‐bis[C(S)NHP(S)(OiPr)2]‐1,10‐diaza‐18‐crown‐6 ( H2LI ), N,N′‐bis[C(S)NHP(S)(OiPr)2]‐1,7‐diaza‐18‐crown‐6 ( H2LII ) and N,N′‐bis[C(S)NHP(S)(OiPr)2]‐1,7‐diaza‐15‐crown‐5 ( H2LIII ). Reaction of the potassium salts of H2LI–III with a mixture of CuI and 2,2′‐bipyridine ( bpy ) or 1,10‐phenanthroline ( phen ) in aqueous EtOH/CH2Cl2 leads to the dinuclear complexes [Cu2(bpy)2LI–III] and [Cu2(phen)2LI–III] . The structures of these compounds were investigated by 1H, 31P{1H} NMR spectroscopy, and elemental analysis. The crystal structures of H2LI and [Cu2(phen)2LI] were determined by single‐crystal X‐ray diffraction. Extraction capacities of the obtained compounds in comparison to the related compounds 1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(=CMe2)CH2P(O)(OiPr)2]‐1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(S)NHP(O)(OiPr)2]‐1,10‐diaza‐18‐crown‐6 towards the picrate salts LiPic, NaPic, KPic. and NH4Pic were also studied. 相似文献
55.
The working conditions were found for the determination of medicinal substances anesthesin (benzocaine,I), novocaine (II), novocainamide (procainamide,III), and sodium 4-aminosalicylate (IV) as their 4,6-dinitrobenzofuroxan derivatives by flow-injection analysis with spectrophotometric detection (λ 510 nm). The
best conditions were attained using a mixture of ethanol (methanol) and a buffer solution of pH 6.68 (30: 70 vol %). The analytical
range for the analytes was 0.08-5.0 μg/mL. The detection limits (3σ,n = 4) were 0.04 (I), 0.05 (II), 0.07 (III), and 0.03 (IV) μg/mL. Procedures for determining 4-aminobenzoic and 4-aminosalicylic
acid derivatives in pharmaceuticals containing ephedrine, atropine, dimedrol, and inorganic salts and in biological fluids
(protein hydrolyzate, blood plasma, and whole blood) were developed. 相似文献
56.
Vladimir D. Kiselev Ilzida I. Shakirova Dmitry A. Kornilov Helen A. Kashaeva Lubov N. Potapova Alexander I. Konovalov 《Journal of Physical Organic Chemistry》2013,26(1):47-53
Solvent, temperature, and high pressure influence on the rate constant of homo‐Diels–Alder cycloaddition reactions of the very active hetero‐dienophile, 4‐phenyl‐1,2,4‐triazolin‐3,5‐dione (1), with the very inactive unconjugated diene, bicyclo[2,2,1]hepta‐2,5‐diene (2), and of 1 with some substituted anthracenes have been studied. The rate constants change amounts to about seven orders of magnitude: from 3.95.10?3 for reaction (1+2) to 12200 L mol?1 s?1 for reaction of 1 with 9,10‐dimethylanthracene (4e) in toluene solution at 298 K. A comparison of the reactivity (ln k2) and the heat of reactions (?r‐nH) of maleic anhydride, tetracyanoethylene and of 1 with several dienes has been performed. The heat of reaction (1+2) is ?218 ± 2 kJ mol?1, of 1 with 9,10‐dimethylanthracene ?117.8 ± 0.7 kJ mol?1, and of 1 with 9,10‐dimethoxyanthracene ?91.6 ±0.2 kJ mol?1. From these data, it follows that the exothermicity of reaction (1+2) is higher than that with 1,3‐butadiene. However, the heat of reaction of 9,10‐dimethylanthracene with 1 (?117.8 kJ mol?1) is nearly the same as that found for the reaction with the structural C=C counterpart, N‐phenylmaleimide (?117.0 kJ mol?1). Since the energy of the N=N bond is considerably lower (418 kJ/bond) than that of the C=C bond (611 kJ/bond), it was proposed that this difference in the bond energy can generate a lower barrier of activation in the Diels–Alder cycloaddition reaction with 1. Linear correlation (R = 0.94) of the solvent effect on the rate constants of reaction (1+2) and on the heat of solution of 1 has been observed. The ratio of the volume of activation (?V≠) and the volume of reaction (?Vr‐n) of the homo‐Diels–Alder reaction (1+2) is considered as “normal”: ?V≠/?Vr‐n = ?25.1/?30.95 = 0.81. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
57.
In terms of coefficients of an equation under consideration, we derive 16 variants of collections of conditions of resolvability of this equation in quadratures. Every collection consists of three identities that interconnect five coefficients appearing in left-hand side of an equation. 相似文献
58.
Airat R. Tuktarov Artur A. KhuzinZulfiya R. Shakirova Natal’ya R. Popod’koUsein M. Dzhemilev 《Tetrahedron letters》2014
The reaction of C60 with EtMgBr and different nitriles in the presence of Ti(Oi-Pr)4 as the catalyst was performed for the first time to give novel fullerotetrahydropyridines. 相似文献
59.
Two N-thiophosphorylated thiosemicarbazides of the common formula RC(S)NHP(S)(OiPr)2 [R = PhNHNH- (1); EtN(NH2)- (2)] have been synthesized and characterized by IR, 1H and 31P spectroscopy, and the single crystal X-ray diffraction method. Single crystal X-ray diffraction studies showed the thiosemicarbazides form both intra- and intermolecular hydrogen bonds, which in turn lead to polymeric chain formation. Moreover, according to the X-ray data of the phenylsubstituted thiosemicarbazide, the formation of intermolecular H?η6-phenyl interactions were established. 相似文献
60.
The methods of preparation and reactivity of aliphatic nitramino alcohols as well as their ethers and esters, which are promising
intermediates in the synthesis of aliphatic nitramines used as the components of gunpowder and fuel compositions, are considered. 相似文献