排序方式: 共有32条查询结果,搜索用时 15 毫秒
1.
Perišić-Janjić Nada U. Ž. Jovanović Bratislav Janjić Natasa J. Rajković Olga S. Antonović Dušan G. 《平面色谱法杂志一现代薄层色谱法》2003,16(6):425-432
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of nine newly synthesized s-tri-azines has been studied by thin-layer chromatography on C18/UV254... 相似文献
2.
Stevo Stevi Bratislav Iri
anin Witold Kosmala Zdenk marda 《Mathematical Methods in the Applied Sciences》2019,42(5):1687-1701
Some formulas for well‐defined solutions to four very special cases of a nonlinear fifth‐order difference equation have been presented recently in this journal, where some of them were proved by the method of induction, some are only quoted, and no any theory behind the formulas was given. Here, we show in an elegant constructive way how the general solution to the difference equation can be obtained, from which the special cases very easily follow, which is also demonstrated here. We also give some comments on the local stability results on the special cases of the nonlinear fifth‐order difference equation previously publish in this journal. 相似文献
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We have analyzed a linear molecular chain with exciton excitations when the number of excitons is not conserved. The dispersion law depends on two independent variables and it is surfaced in a 3D plot. The same conclusion is valid for the concentrations of excitons and exciton pairs. As it was expected, physical characteristics of the finite chain depend on spatial coordinates. All results are compared to the corresponding results of an infinite chain. 相似文献
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Perišić-Janjić Nada U. Jevrić Lidija R. Bončić-Caričić Gordana A. Jovanović Bratislav Ž. 《平面色谱法杂志一现代薄层色谱法》2001,14(4):277-282
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of four groups of s-triazine derivatives (15 compounds) has been studied on aminoplast and cellulose... 相似文献
6.
Crystallization of silver trifluoroacetate from chloroform solutions containing triphenylphosphine sulfide affords a trigonal and a monoclinic form of a 6:4 complex {[CF3C(O)OAg]6(Ph3PS)4} of C2 symmetry with different amounts of chloroform in the crystals. With the Ph3PS components as template molecules, the CF3C(O)OAg units are assembled to form a 6-membered metallacycle codetermined by metallophilic bonding and enclosed by a 24-membered ring [AgOCO]6. A complex of the type [LAgOC(O)CF3]2, with L representing the isocyanide ligand pTolSO2CH2NC, has been shown to have a conventional bicyclic structure with three-coordinate silver atoms engaged in transannular metallophilic interactions. 相似文献
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Jovanović BZ Perić-Grujić AA Marinković AD Vajs VV 《Rapid communications in mass spectrometry : RCM》2002,16(21):2044-2047
Mass spectrometry has been applied in order to study the main fragmentation routes of some 4-pyrimidene carboxylic acids. Differences in fragmentation were caused by the nature of the substituent in position 2 of the pyrimidine ring, while the methyl group in position 1, 3 or 6 did not influence the fragmentation route. 相似文献
9.
A LFER Kinetic Study of The Reaction of 5‐Substituted Orotic Acids with Diazodiphenylmethane 下载免费PDF全文
Fathi H. Assaleh Aleksandar D. Marinković Jasmina B. Nikolić Saša Ž. Drmanić Danijela Brković Nevena Prlainović Bratislav Ž. Jovanović 《国际化学动力学杂志》2016,48(7):367-378
Linear free energy relationships (LFER) were applied to the kinetic data for the reaction of 5‐substituted orotic acids, series 1 , with diazodiphenylmethane (DDM) in N,N–dimethylformamide and compared with results obtained for 2‐substituted benzoic acids, series 2 . The correlation analysis of the kinetic data with σ substituent parameters was carried out using SSP (single substituent parameter) methods. From the sign and value of proportinality constant ρ, lower sensitivity to the substituent effect was obtained in series 1 , 0.876, than in the series 2 , 1.877. Evaluation of substituent “ortho‐effect” was performed using the Charton model, which includes the steric substituent parameter, and Fujita and Nishioka's model, which describes the total ortho‐effect as contribution of ordinary polar effect, the ortho‐steric and ortho‐polar effects. Results of correlations, obtained by using the Charton model, showed highest contribution of the polar effect, 0.861 vs. 2.101, whereas the steric effect is of lowest significance, 0.117 vs. 0.055, for series 1 and 2 , respectively. Also, a low negative value of coefficient with the steric effect, –0.08, obtained from the Fujita–Nishioka model indicated low steric effect, influencing a decrease of the reaction rate in series 1 . The structural and substituent effects were also studied by using the density functional theory method, and together with kinetic data, it gave a better insight into the influence of the effect of both geometry and substituent on the π?electron density shift induced reactivity of investigated acids. 相似文献
10.
Alan R. Katritzky Giuseppe Musumarra Kumars Sakizadeh Sayed M.M. El-Shafie Bratislav Jovanovic 《Tetrahedron letters》1980,21(28):2697-2699
-Substituents in 2, 4, 6-triphenylpyridiniums are transferred to piperidine, morpholine and pyridine by unimolecular and/or bimolecular processes in chlorobenzene solution. These processes are quite distinct and afford no evidence for a mechanism intermediate between SN1 and SN2. 相似文献