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1.
Structure and Stability of Quaternary Ammonium Interhalides: Experimental and Quantum-Chemical Study
Simonyan S. S. Kletskii M. E. Chernov'yants M. S. Gol'eva V. E. 《Russian Journal of General Chemistry》2003,73(4):575-582
The electronic structure of a series of ammonium interhalides [R1R2R3R4N]XI2, where R1 = CH3, C2H5, C3H7, F, H; R2 = R3 = R4 = CH3, H; X = Cl, Br, I, was studied by ab initio calculations (RHF/3-21G, RHF/HW, MP2/HW). The thermodynamic stability of these compounds correlates with the strength of the hydrogen bond N-H···X and three-center interhalide bond X-I-I. Calculations confirmed that, in polar solvents, these compounds preferably decompose to [R1R2R3R4N]+ and XI2
- (with subsequent decomposition of the anion), and in nonpolar solvents, to the neutral species [R1R2R3R4N]X and I2. The calculation results were compared to the experimental data obtained by single crystal X-ray diffraction, 1H NMR spectroscopy, and spectrophotometry. 相似文献
2.
Kazheva O. N. Aleksandrov G. G. D'yachenko O. A. Chernov'yants M. S. Simonyan S. S. Lykova E. O. 《Russian Journal of Coordination Chemistry》2004,30(10):739-746
Complex formation in systems containing 3-carboxypropyltriphenylphosphonium or tetraphenylphosphonium bromide, molecular iodine, and chloroform solution was compared. The maximum number of iodine molecules coordinated by bromides in the solution was established by spectrophotometric method using a function of average iodine number and the stability constants of the complexes were determined. The diiodobromide [(C6H5)4P]BrI2 was studied by X-ray diffraction analysis. The ab initio calculations were performed for [Y(R)4]I3 (Y = N, P, As; R = CH3, C6H5). The obtained experimental data and the correlations with the results of quantum-chemical calculations revealed that the tetraphenylphosphonium cation binds diiodobromide anions through the terminal halogen atoms with equal probability. 相似文献
3.
Iodohalides and halides of the choline series were separated by capillary electrophoresis using an unmodified fused-silica capillary. The developed procedures ensure the determination of iodohalides in the presence of ammonium ions. They were tested in the analysis of model pharmaceuticals of the composition organic iodohalide : polyvinyl pyrrolidone (PVP) (1 : 4). The proposed procedure ensures the estimation of the concentration of choline-mimetic substances in the range from 1 × 10–5 to 5 × 10–3 M. 相似文献
4.
V. A. Anisimova O. I. Askalepova K. N. Bagdasarov M. S. Chernov'yants 《Chemistry of Heterocyclic Compounds》1988,24(3):281-284
Refluxing 2-cyanomethylbenzimidazole in alcohol with alkyl halides led to low yields of N-alkylated products. Addition of base to the reaction mixture shifted the course of the reaction to form mainly N,C-dialkyl substituted products. In DMF or with an excess of alkyl halide at elevated temperature both N-mono- and N,N-dialkyl substituted materials were formed together.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 345–349, March, 1988. 相似文献
5.
Chernov'yants MS Khohlov EV Bondarenko GI Burykin IV 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,81(1):640-644
The charge-transfer complexes (CTC) of few thioamide: 1-methylimidazoline-2-thione (MMI), 3-methyl-1-ethoxycarbonilimidazoline-2-thione (Carb), 5-methylbenzimidazoline-2-thione (BIZ), benzothiazoline-2-thione (BTZ), benzoxazoline-2-thione (BOZ) as σ-donors and diiodine as σ-acceptor were studied by spectroscopic methods (UV/Vis, (1)H NMR). CTC formation constants of thioamides with diiodine were determined using the function of the average-iodine number. The charge-transfer complexes of thioamides as π-donors with tetracyanoethylene (TCNE) as π-electron acceptor, were studied by UV-spectroscopy in dichloromethane and chloroform solutions. The mechanism of interaction MMI and Carb with TCNE have been studied by EPR spectroscopy. Spectral characteristics and formation constants are discussed in the terms of electron donor affinity of thioamides and the nature of the organic solvent used. The ionization potentials of donors were estimated from the CT transition energies of their complexes. The photolytic equilibrium constants of five thioamides are determined using pH-metric titrations. 相似文献
6.
The history of the department, its educational activity, the main fields of its scientific work, and the main achievements are presented. 相似文献
7.
M. S. Chernov'yants V. E. Gol'eva A. I. Pyshchev 《Journal of Analytical Chemistry》2003,58(2):139-143
The following biologically active diiodohalides of organic cations were studied: N-cetylpyridinium, trimethylbenzylammonium, triethylbenzylammonium, and N,N-dimethylmorpholinium diiodochlorides; N-cetylpyridinium, tetramethylammonium, tetrabutylammonium, and N,N-dimethylmorpholinium diiodobromides; and N,N-dimethylmorpholinium and butyroylcholinium triiodides. A simple and rapid procedure was proposed for the determination of the above compounds; it is based on the conversion of organic diiodohalides into the corresponding triiodides (300 nm 4 × 104; 370 nm 2 × 104) in the presence of excess potassium iodide (RSD 2%). An extraction–spectrophotometric method was developed for the quantitative determination of the biologically active compounds in pharmaceutical dosage forms based on their ion associates with anionic dyes, erythrosine (m
min = 1.25–3.30 g; RSD 3%) and Bromothymol Blue (m
min = 3.85 g; RSD = 3%), or a cationic dye—1,3-dimethyl-2-(4-morpholinophenyl)azobenzimidazolium phenylsulfate (m
min = 2.32–8.26 g; RSD 4%). The developed procedures were used for monitoring drug substances in model pharmaceutical preparations (RSD 4%). 相似文献
8.
Kazheva O. N. Aleksandrov G. G. D'yachenko O. A. Chernov'yants M. S. Lykova E. O. Tolpygin I. E. Raskita I. M. 《Russian Journal of Coordination Chemistry》2004,30(8):599-603
Complexation in the N-ethylquinolinium iodide–molecular iodine system in a chloroform solution is studied. The stability constant of N-ethylquinolinium triiodide (I) is determined by spectrophotometric methods of stoichiometric dilution using the average iodine number function. Compound I with the [C9H7NC2H5]I3 composition is studied by X-ray diffraction analysis. The crystal structure is formed by alternating layers of cations arranged by the ladder type and triiodide anions with equalized interatomic distances. The triiodide anions are linked to form chains through strongly shortened intermolecular contacts. 相似文献
9.
Kazheva O. N. D'yachenko O. A. Chernov'yants M. S. Gol'eva V. E. Pyshchev A. I. 《Russian Journal of General Chemistry》2002,72(10):1521-1524
The complex formation in the system bis[2-(trimethylammonio)ethyl] succinate diodide-iodine involves no more than two iodine molecules. The crystal structure of the salt [(CH3)3N(CH2)2OCOCH2]2(I3)2 is formed by layers of inorganic anions (I3
-) and organic dications (centrosymmetric dications {[(CH3)3N · (CH2)2OCOCH2]+}2), evenly alternating along the a axis. The crystal structure of the salt [(CH3)3N(CH2)2·OCOCH2]2(I3)2(I2)0.5 is formed by organic and inorganic layers evenly alternating along the [011] diagonal, with a centrosymmetric iodine molecule. 相似文献
10.
A new capillary electrophoretic (CE) method was developed for the simple and selective determination of iodine in 0.5 mol l(-1) NaCl. The proposed method is based on the in-capillary derivatization of iodine with thiosulfate ions using the zone-passing technique and direct photometric detection of the iodide and tetrathionate formed. The optimal conditions for the separation and derivatization reaction were established by varying the concentration of iodine, electrolyte pH and applied voltage. The optimized separations were carried out in phosphate electrolyte (pH 6.86) using direct photometric detection at 253.7 nm. Common photometric detection absorbing anions such as Cl(-), NO(2)(-), S(2)O(3)(2-) did not give any interference. Valid calibration (r(2) = 0.994) is demonstrated in the range 16.5-198.1 mg l(-1) of iodine. The detection limit (calculated according to K. Doerffel, Statistik in der analytischen Chemie, 1990) was 11.53 mg l(-1) (by iodide peak area) and 8.45 mg l(-1) (by tetrathionate peak area). The proposed system was applied to the determination of iodine after oxidation of iodide in underground water. 相似文献