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81.
Anife Ahmedova Nikola Burdzhiev Samuele Ciattini Elena Stanoeva Mariana Mitewa 《Comptes Rendus Chimie》2010,13(10):1269-1277
The current study describes the synthesis of a new 1,3-indandione derivative with conjugated N-phenylaza-15-crown-5 moiety (4). The crystal structure of compound 4 was solved and its optical properties were studied in various solvents and in presence of alkaline and alkaline-earth metal ions. Quantum chemical (DFT) methods were employed to describe the structure and the optical properties of the studied compound and its complexes. The obtained results indicated that the synthesis of compound 4 using acid-catalyzed aldol reaction between 2-acetyl-1,3-indandione and the corresponding aldehyde is accompanied with an unexpected deacetylation step. In this way, the N-phenylaza-15-crown-5 moiety is directly conjugated with the 1,3-indandione fragment, known as a very strong electron acceptor. Therefore, the absorption spectra of 4 are only slightly influenced by complexation with Ba2+ and Sr2+ ions. 相似文献
82.
83.
Unequal-sphere packing model is applied for the simulation of large number of hexagonal adlayer structures with surface coverage between theta=13 and theta=1 on the hexagonal substrate, with atomic radius of the adsorbate and substrate atoms as the only input. Each structure is characterized with respect to collective adlayer properties: the average adlayer height and the adlayer roughness. The distribution of hexagonal arrangements is presented in a special plot, which can be used for identification and characterization of hexagonal adlayers of different surface coverages and atomic registries. The most likely structures are related to the extreme values of our model parameters. The usefulness of this methodology is successfully demonstrated by comparison with some real adsorbate-substrate systems, i.e., halogens and rare gases adsorbed on (111) surface. Besides the agreement with experimental results, our model offers new insight into the formation of atomic adlayers and detailed analysis of the atomic registry. We believe that our approach will be of use for identification of probable structures among the large number of combinatorial possibilities in theoretical studies and for better interpretation of experimental results (i.e., scanning-tunneling microscopy images of atomic adlayers). 相似文献
84.
Nikola T. Burdzhiev 《Tetrahedron》2006,62(35):8318-8326
The reaction between glutaric anhydride (1) and N-benzylidenebenzylamine (3) was studied in detail by 1H NMR spectroscopy under different reaction conditions. The major product was (±)-trans-1-benzyl-6-oxo-2-phenylpiperidine-3-carboxylic acid (2), which was converted into new substituted piperidin-2-ones via transformations of the carboxylic group. The final products are expected to possess pharmaceutical activities, and the relevant screenings are in course. 相似文献
85.
Thomas Zimmermann Nikola Pustet Albrecht Mannschreck 《Monatshefte für Chemie / Chemical Monthly》2000,131(10):1083-1090
Summary. The enantiomers of substituted spiro[cyclohexadiene-dihydroacridines] were separated by enantioselective liquid chromatography
with the sorbent/solvent systems triacetylcellulose/methanol, tris-(3,5-dimethylphenylcarbamoyl)-cellulose/silica gel (Chiralcel
ODTM)/n-heptane/2-propanol, and (+)-poly-(trityl methacrylate)/silica gel/n-heptane/2-propanol. Interconversion barriers of the enantiomers were determined for a series of derivatives by thermal racemization.
Electrocyclic ring opening/ring closure in terms of the Woodward-Hoffmann rules is discussed for the enantiomerization mechanism; the interconversion of the enantiomers by enolization is ruled out
by deuterium exchange experiments.
Received April 3, 2000. Accepted April 12, 2000 相似文献
86.
Multifaceted Studies of the DNA Interactions and In Vitro Cytotoxicity of Anticancer Polyaromatic Platinum(II) Complexes 下载免费PDF全文
Benjamin J. Pages Dr. Jennette Sakoff Dr. Jayne Gilbert Prof. Alison Rodger Dr. Nikola P. Chmel Nykola C. Jones Dr. Sharon M. Kelly Dale L. Ang Prof. Janice R. Aldrich‐Wright 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(26):8943-8954
This study reports a detailed biophysical analysis of the DNA binding and cytotoxicity of six platinum complexes (PCs). They are of the type [Pt(PL)(SS‐dach)]Cl2, where PL is a polyaromatic ligand and SS‐dach is 1S,2S‐diaminocyclohexane. The DNA binding of these complexes was investigated using six techniques including ultraviolet and fluorescence spectroscopy, linear dichroism, synchrotron radiation circular dichroism, isothermal titration calorimetry and mass spectrometry. This portfolio of techniques has not been extensively used to study the interactions of such complexes previously; each assay provided unique insight. The in vitro cytotoxicity of these compounds was studied in ten cell lines and compared to the effects of their R,R enantiomers; activity was very high in Du145 and SJ‐G2 cells, with some submicromolar IC50 values. In terms of both DNA affinity and cytotoxicity, complexes of 5,6‐dimethyl‐1,10‐phenanthroline and 2,2′‐bipyridine exhibited the greatest and least activity, respectively, suggesting that there is some correlation between DNA binding and cytotoxicity. 相似文献
87.
88.
The hydrolysis of the iron(III) ion in sodium chloride medium without organic ligands and in the presence of acetate and EDTA ligands was studied by emf method, at 25°C. The data indicate the effect of the organic ligands. In the presence of acetate ion the beginning of hydrolysis of the iron(III) ion is slightly shifted toward lower pH values, while in the presence of EDTA, as a strong complex forming ligand, the beginning of hydrolysis is shifted toward higher pH values for 2.5 pH units. 相似文献
89.
Michael Neumann-Spallart o. Univ. Prof. Dr Nikola Getoff 《Monatshefte für Chemie / Chemical Monthly》1975,106(6):1359-1367
The photolysis of 0.5 mole/l monochloroacetic acid in aqueous solution at 253.7 nm was studied and as products were determined: Cl? (?=0.34), CH2OHCOOH (?=0.19), CO2 (?=0.12), CH3COOH (?=0.08), HCHO (?=0.004) and CH4 (?=0.001). Based on these results a probable reaction mechanism is discussed to explain the rather complicated process. 相似文献
90.
Ljiljana S. Jovanović Nikola J. Ević Luka J. Bjelica Biljana F. Abramović Ferenc F. Gaál Nándor L. Rehák 《Monatshefte für Chemie / Chemical Monthly》1992,123(12):1071-1079
Summary The acid-base properties of the -oxo bridged dimeric iron complexes [FeL]2O with the ligands based on S-alkyl-1,4-bis(substituted salicylidene)isothiosemicarbazide and a tetramer with S-methyl-1,4-bis(salicylidene)isothiosemicarbazide, {[FeL]2O}2I3·I2, were investigated by cyclic voltammetry at glassy carbon electrode inDMF. Studies were carried out in the presence of either a weak (phenol) or a strong (HClO4 aq.) acid. The stoichimoetry of the reaction, changes in the general voltammetric pattern and the electrode reaction mechanism were discussed. These studies served as the basis for three-electrode amperometric titrations to determine the content of several of these complexes.
Voltammetrische und titrimetrische Untersuchung der Säure-Base-Eigenschaften einiger -oxo dimerer Eisen(III)-Komplexe inDMF-Lösungen
Zusammenfassung Die Säure-Base-Eigenschaften einiger dimerer -oxo-Eisen(III)-Komplexe [FeL]2O mit Liganden auf Basis von 1,4-bis(substituierten Salicyliden)S-(alkyl)isothiosemicarbaziden sowie eines tetrameren Komplexes mit 1,4-Bis(salicyliden)S-methylisothiosemicarbazid, {[FeL]2O}2I3·I2, wurden mittels zyklischer Voltammetrie an der Glaskohlenstoffelektrode inDMF-Lösungen untersucht. Die Messungen wurden in Gegenwart entweder einer schwachen (Phenol) oder einer starken (HClO4 aq.) Säure ausgeführt. Die Stöchiometrie der Reaktion, die Änderungen der voltammetrischen Kurven und der Elektroden-Reaktionsmechanismus wurden diskutiert. Diese Untersuchungen stellten eine Basis für Drei-Elektroden amperometrische Titrationen dar, die für die Bestimmung des Gehalts einiger dieser Komplexe angewendet wurden.相似文献