卷 87, 编号 5 (2017)
- 年: 2017
- 文章: 37
- URL: https://journals.rcsi.science/1070-3632/issue/view/13617
Article
Structure, magnetic, and electrical properties of bismuth niobates doped with d-elements: XVI. Magnetic properties of manganese-containing solid solutions of bismuth orthoniobate BiNiO4
摘要
Magnetic susceptibility and ESR properties of manganese-containing solid solutions of bismuth orthoniobate BiNb1–xMnxO4–δ have been studied. Mn(II), Mn(III), and Mn(IV) atoms as well as their dimers exhibiting antiferro- and ferromagnetic types of exchange have been found in the solid solutions. Parameters of the exchange interactions in the clusters and the distribution of monomers and dimers of manganese atoms in the solid solutions have been calculated as functions of the paramagnetic atom fraction.
Special features of preparation of nanosized zirconium diboride powders of various dispersity
摘要
Products of the zirconium powder reaction with amorphous boron in a Na2B4O7 ionic melt at 650–850°C and those of the ZrCl4 reaction with NaBH4 at 300–725°C have been studied by means of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry, and elemental analysis. At temperature ≥750°C, single-phase ZrB2 with the particle size of 60–80 nm is formed in a Na2B4O7 ionic melt, whereas the ZrB2 powder obtained via the reaction of ZrCl4 with NaBH4 at temperature ≥575°C consists of particles differing in the shape, some of which are close to spherical with diameter of 10–35 nm.
Modification of magnesium silicate with 15(2)-methyl ester of 13(1),17(3)-diamino-N,N′-bis(2-hydroxyethyl)-13(1),17(3)-dioxochlorin e6
摘要
Magnesium silicates modified with 15(2)-methyl ester of 13(1),17(3)-diamino-N,N′-bis(2-hydroxyethyl)-13(1),17(3)-dioxochlorin e6 have been synthesized by heat treatment in water containing small fraction of ethanol. X-ray phase analysis, differential scanning calorimetry, thermogravimetry, and UV-Vis spectroscopy studies have shown that the synthesized samples contain individual molecules of 15(2)-methyl ester of 13(1),17(3)-diamino-N,N′-bis(2-hydroxyethyl)-13(1),17(3)-dioxochlorin e6 held on the inorganic substrate surface by electrostatic interaction and hydrogen bonding.
Cyclophanes: Simulation of the formation enthalpy by quantum-chemical methods
摘要
Comparison of experimental values of gas-phase formation enthalpy of cyclophanes with the results of semiempirical quantum-chemical simulation has revealed good linear correlation with the PM-3 data. Using the derived equation, formation enthalpies of 30 cyclophanes have been predicted.
X-ray emission spectroscopy and theoretical study of the electronic structure of hexamethyldisiloxane and octamethylcyclotetrasiloxane
摘要
Electronic structure of hexamethyldisiloxane and octamethylcyclotetrasiloxane has been studied by means of X-ray emission spectroscopy and quantum-chemical simulation at the density functional theory level. From the analysis of the fine structure of X-ray emission SiKβ1-spectra and simulated densities of electronic states, the special features of chemical interactions of Si, O, and C atoms in these molecules are determined.
Electrochemical amination of benzene in aqueous-acetic solutions of sulfuric acid
摘要
Indirect cathodic amination of benzene with hydroxylamine in the presence of Ti(IV)/Ti(III) mediator system in aqueous media containing 4–11 mol/L H2SO4 and 13–5.5 mol/L AcOH has been studied. Aniline, diphenyl, and isomeric phenylenediamines are the electrolysis products at 25–60°C. The increase in temperature favors the formation of the monoamino compound. Aniline yield with respect to hydroxylamine at complete conversion of the latter has reached 78.7%, mass fraction of aniline being 97.1%.
The interaction of low- and medium-chlorinated biphenyls with sodium methoxide with the account for thermodynamic modeling
摘要
The interaction of low- and medium-chlorinated congeners of polychlorinated biphenyls of the Trikhlorbifenil technical mixture with sodium methoxide in dimethylsulfoxide has been studied by means of experimental and calculation methods. Thermodynamic modeling of the process has revealed exclusive formation of the methoxy derivatives in the studied process. whereas the experiment has revealed the formation of methoxy, hydroxy, and methoxy(hydroxy) derivatives of congeners of polychlorinated biphenyls.
Synthesis and physico-chemical properties of ionic liquids—3-methyl-1-alkyloxycarbonylmethylpyridinium hexafluorophosphates
摘要
Ionic liquids based on 1-alkyloxycarbonylmethyl-3-methylpyridinium and Cl– and PF6– anions have been synthesized. The conductivity of their solutions in acetonitrile and the thermal stability over 25–500°C in air have been determined.
Luminescence and photochemical properties of hydrazones of aromatic aldehydes
摘要
Luminescence and photochemical properties found by us earlier for several hydrazones of aromatic aldehydes have been shown to be characteristic also of other compounds of this class. The structure of the product of reversible photochemical reaction of hydrazones of aromatic aldehydes is explained by specific interactions between the lone electron pairs of the two vicinal nitrogen atoms in the molecule of hydrazine. Compounds possessing photochromic properties have been suggested and prerequisites of application of luminescent hydrazones as luminophors have been formulated.
Synthesis of 4-hydroxy-5-methyl-2-[2-(4-oxo-4H-chromen-3-yl)ethenyl]-6H-1,3-oxazin-6-ones and their reaction with hydrazine
摘要
4-Hydroxy-6H-1,3-oxazin-6-ones containing a 3-vinylchromone fragment in the 2-position were synthesized. The direction of their reactions with hydrazine hydrate was found to depend on the solvent nature. The reaction in protic solvents (methanol, acetic acid) resulted in recyclization of both oxazine ring to 1,2,4-triazole and pyranone ring to pyrazole. Aprotic acetonitrile favored attack of hydrazine exclusively on the oxazine ring, while the 3-vinylchromone fragment remained intact.
Synthesis of podands modified with thiosemicarbazide and fluoroalkyl(hydroxy)pyrazoline fragments
摘要
1,8-Bis(diisothiosemicarbazido)-3,6-dioxaoctane have been synthesized by subsequent treatment of 2,2′-(ethylenedioxy)bisethylamine with carbon disulfide, sodium chloroacetate, and hydrazine hydrate. 1,8-Bis- (diisothiosemicarbazido)-3,6-dioxaoctane has reacted with lithium 1,1-difluoropenta-2,4-dionate in glacial acetic acid to yield 1,8-bis[5R*,5′R*(5-hydroxy-5-difluoromethyl-4,5-dihydro-3-methyl-1H-pyrazol-1-yl)-1-carbothioamido]-3,6-dioxaoctane. The molecular and crystal structure of the product has been determined by X-ray diffraction analysis.
Efficient synthesis of bis(1,5,3-dithiazepanes). Sorption of palladium(II) from nitric acid solutions
摘要
Bis(1,5,3-dithiazepanes) have been synthesized via cyclocondensation of aliphatic α,ω-diamines and hydrazine with formaldehyde and ethane-1,2-dithiol. Palladium(II) sorption with bis(1,5,3-dithiazepanes) from nitric acid solutions has been studied via a static method. Bis(1,5,3-dithiazepanes) efficiently extract palladium(II) from 0.1−4 mol/L nitric acid solutions at room temperature.
Synthesis of acyclic three-unit products with 3-alkyl-1,3,4-thiadiazoline fragments
摘要
A method of synthesis of acyclic trimeric products based on 3-alkyl-5-amino-2-imino-1,3,4-thiadiazoline in the presence of calcium chloride as catalyst has been suggested.
Functionalization of 5-(4-alkoxybenzyl)-4-R-4H-1,2,4-triazole-3-thiols. Synthesis of novel DNA methylation inhibitors
摘要
Aminomethylation and cyanoethylation reactions of 5-(4-alkoxybenzyl)-4-methyl(phenyl, allyl)-4H-1,2,4-triazole-3-thiols have been investigated. According to NMR spectroscopy data, the reactions occur at the nitrogen atom Ν2. The effect of the synthesized compounds on cancer DNA methylation has been evaluated.
Photostability and fluorescence parameters of porphyrinoids: The effect of the macrocycle structure and the medium
摘要
The effects of the macrocycle structure and the medium nature on photodecomposition of porphyrinoids under UV irradiation have been studied. The influence of protonation, nonplanar structure of the molecule, and reactivity of NH bonds on the photostability of porphyrins and their analogs has been shown.
Reactions of N-(2,2-dichloro-1-cyanoethenyl)-N′-methyl(phenyl)ureas with aliphatic amines
摘要
Novel derivatives of 3,3-dichloroprop-2-enenitrile containing methylurea or phenylurea fragments have been synthesized. The obtained N-(2,2-dichloro-1-cyanoethenyl)-N′-methyl(phenyl)ureas undergo intramolecular cyclization in the presence of triethylamine to form 4-(dichloromethylidene)-5-imino-1-methyl (phenyl)imidazolidin-2-ones. Reactions of N-(2,2-dichloro-1-cyanoethenyl)-N′-methylurea with aliphatic amines have afforded 4-(alkylamino)-4-(dichloromethyl)-5-imino-1-methylimidazolidin-2-ones.
Synthesis of chiral phosphonobenzaldehydes and phosphonotyrosine
摘要
A method for obtaining of chiral phosphonobenzaldehydes has been developed. The Abramov reaction between dimenthyl phosphite and 4-diethoxymethylbenzaldehyde followed by separation of stereoisomers has yielded enantiomerically pure (1S)- and (1R)-1-hydroxyphosphonates. The resulting phosphonates, after removal of acetal protection, have been converted to (1S)- and (1R)-1-hydroxymethylphosphonobenzaldehydes. By reacting with (diethylamino)trifluorosulfurane, 1-hydroxyphosphonates have been converted to 4-(1-fluoromethyl)phosphonobenzaldehydes. The synthesized chiral phosphonobenzaldehydes are convenient chiral reactants for the preparation of phosphorus analogs of natural compounds, as has been shown with the example of synthesis of the phosphonium analog of phosphotyrosine.
Carboxyl derivatives of phosphazenes
摘要
The review describes the modern methods of synthesis and chemical modification of carboxylcontaining phosphazenes. The possibility of their use in the synthesis of polyamides, epoxy resins, star-shaped and structured polymers, hydrogels, and metal complexes is considered. Carboxyl-containing phosphazenes and their derivatives are of great interest for medicine, electronics, photonics, and design of multipurpose hightech composite materials, offering wide opportunities for further research and application.
Synthesis and complex formation of spirobenzopyranindolines containing rhodamine fragment
摘要
The interaction of 7-hydroxy-6-formyl-substituted spiropyrans and Rhodamine B aminoethylamide has afforded spirobenzopyrans containing rhodamine fragment bound to the benzopyran part via the methyleneaminoethyl spacer. The prepared spiropyrans exist in the spiropyran-spirolactam form in the acetone solution and exhibit weak photochromism at 283 K. The addition of Cd, Co, Ni, and Zn perchlorates to the spiropyrans solution results in the coloration due to the complex formation. The composition and stability of the complexes has been determined by means of spectrophotometry.
Dinuclear copper(I) complexes with substituted benzimidazole ligands. Synthesis and photo- and electroluminescent properties
摘要
New dinuclear copper(I) complexes with bridging bis-diimine ligands were synthesized on the basis of benzimidazole derivatives. The obtained complexes showed photo- and electroluminescent properties. Copper-containing emitters exhibited yellow, orange, and yellow–green electroluminescence with a maximum brightness of 1166 cd/m2.
Electrochemical synthesis of anhydrous luminescent Tb3+ complexes with aromatic and heterocyclic carboxylic acids
摘要
The electrochemical synthesis of anhydrous terbium(III) complex compounds TbL3 and Tb2L3 with several aromatic and heterocyclic carboxylic acids has been performed. Thermal stability of the synthesized complexes has been studied by means of thermogravimetry, and terbium(III) 4-tert-butylbenzoate has been found the most thermally stable (up to 400°C). Luminescent properties of the obtained compounds have been studied, and the terbium(III) complex with 2,3-pyridinedicarboxylic acid has exhibited the most efficient luminescence.
Interaction of ferrocene with styrene and methyl methacrylates in the media of different polarity
摘要
The interaction of ferrocene with styrene and methyl methacrylate in media of different polarity (hexane, tetrachloromethane, and ethanol) has been studied by means of UV spectroscopy using the isomolar series method. For both monomers, intermediate complexes are formed, the medium polarity significantly affecting the complexes formation. Ferrocene acts differently in the interaction with styrene (being the electron acceptor) and methyl methacrylate (being the electron donor). It has been discovered that only in the case of ethanol a charge-transfer complex between ferrocene and styrene is formed. Possible structures of the intermediate complexes have been suggested.
Complex formation of daunomycin with poly(vinylpyrrolidone) and poly(ethylene glycol)
摘要
Complexes of the anthracycline antitumor antibiotic daunomycin with biocompatible polymer carriers, poly(vinylpyrrolidone) and poly(ethylene glycol), have been studied. According to the UV–visible absorption spectroscopy and dynamic light scattering data, variation of the weight ratio of the components leads to the formation of antibiotic–polymer complexes in which the polymer is linked through hydrophobic and electrostatic interactions to certain functional groups of the antibiotic molecules. The concentration constants for the complex formation have been calculated.
Effect of ferrocene on the synthesis of graft copolymers of vinylpolysiloxane and styrene
摘要
The effect of ferrocene on the synthesis of graft poly(dimethylsiloxanes) by radical copolymerization of a polysiloxane containing terminal trivinylsiloxy groups with styrene. The backbone in the synthesized graft copolymers is formed by a linear poly(dimethylsiloxane) with a part of its vinyl groups involved in grafting polystyrene chains. The products were studied by gel permeation chromatography, 1Н NMR spectroscopy, and optical microscopy.
Kinetic features of the reaction of polyvinyl alcohol with epichlorohydrin in an alkaline medium
摘要
The kinetics of the reaction of polyvinyl alcohol with epichlorohydrin in an aqueous sodium hydroxide solution has been studied. The process rate has been shown to be diffusion-limited. Size exclusion chromatography data have revealed that polyvinyl alcohol chain branching proceeds slower than the nucleophilic substitution of the hydroxyl groups of polyvinyl alcohol with introduction of glycidyl groups.
Synthesis of N-methylpiperidin-4-one derivatives and evaluation of their anti-endometrial cancer activity
摘要
Four novel N-methylpiperidin-4-one derivatives were synthesized and characterized by IR, 1H NMR, HRMS, and single crystal X-ray crystallography. The anticancer activity of these compounds was studied on five human endometrial cancer cell lines (RL-95-2, HEC-1A, HEC-1B, AN3CN and HECCL-1). Efficient antitumor effect was found for the 3,5-difluorophenyl- and 3-cyanophenyl-substituted derivatives.
Synthesis and molecular docking studies of novel 2-phenyl-4-{4-[(1-phenyl-1H-1,2,3-triazol-4-yl)methoxy]benzylidene}oxazol-5(4H)-one derivatives
摘要
2-Phenyl-4-{4-[(1-phenyl-1H-1,2,3-triazol-4-yl)methoxy]benzylidene}oxazol-5(4H)-one derivatives were synthesized by click chemistry reactions. Exploration of molecular interaction of the obtained compounds, performed through molecular docking studies with α-glucosidase, revealed the high docking scores (LibDock) in the range of 135.056–126.164 as compared to acarbose (136.345).
One-pot synthesis of some 2-amino-4H-chromene derivatives using triethanolamine as a novel reusable organocatalyst under solvent-free conditions and its application in electrosynthesis of silver nanoparticles
摘要
A wide variety of 2-amino-4H-chromene derivatives with diverse substituents on the 4H-chromene ring were efficiently prepared via one-pot three-component reaction of an aromatic aldehyde and malononitrile with 2-hydroxynaphthalene-1,4-dione, ethyl acetoacetate, or naphthols in the presence of triethanolamine as a new organocatalyst under solvent-free conditions. The procedure is transition metal-free and environmentally friendly approach to various 2-amino-4H-chromene derivatives. Its advantages include short reaction time, high yields, low cost, and straightforward work-up. Triethanolamine is an efficient reusable catalyst. 2-Amino-4H-benzo[g]chromenes (ABgC) were applied as novel components of electro synthesis of silver nanoparticles.
An efficient green approach to aldol and cross-aldol condensations of ketones with aromatic aldehydes catalyzed by nanometasilica disulfuric acid in water
摘要
Aldol and cross-aldol condensations of aromatic aldehydes with various ketones in the presence of nanometasilica disulfuric acid (NMSDSA) as heterogeneous catalyst are presented. The catalyst was prepared according to the developed earlier method using inexpensive and readily available starting materials. The highly active catalyst gave excellent yields of the desired aldol products without self-condensation reaction taking place. Reaction times were short, the procedure and work-up were simple, and no volatile or hazardous organic solvents were involved. The catalyst could be recovered three times with only slight reduction in activity.
Cyclopropyl-containing sulfonyl amino acids: Exploring the enantioseparation through chiral ligand-exchange chromatography
摘要
In the scope of a broader study focused on glutamate receptors regulators, we have been engaged in synthesis, analysis and pharmacological characterization of rigid analogues of glutamic acid. These compounds exhibited the bioisosteric replacement of the distal carboxylic group with the sulfonic one. Besides the sophisticated synthetic approach, we targeted preparation of a series of cyclopropyl-containing sulfonyl amino acids and development of a chromatographic enantioselective method suitable for distinguishing and quantifying the resulting isomers. Due to chelating ability, the chiral ligand-exchange chromatography (CLEC) was used for diastereo- and enantioseparation of the synthesized compounds. The CLEC-based enantioseparation was achieved by using a chiral mobile phase (CMP) system with N,N-dimethyl-(S)-phenylalanine [(S)-DMP] as the chiral selector. Only one of the investigated enantiomeric pairs was undiscriminated with the employed CLEC–CMP system which, very importantly, produced the simultaneous diastereo- and enantioseparation of two compounds of the series. Furthermore, the large α and RS values computed for three enantiomer pairs could be a good basis for a successful scale-up to a semi-preparative level.
Porous hierarchical magnesium oxide-based heterogeneous catalyst for the Knoevenagel condensation
摘要
Herein, an operationally facile and efficient Knoevenagel reaction catalyzed by porous hierarchical MgO/Mg(OH)2 is presented. Condensation of various aldehydes with malononitrile proceeds under mild conditions and gives the target products with high yields.
Physicochemical, spectroscopic, and anti-tumor studies of cefradine complexes with Ca(II), Zn(II), Fe(III), Au(III), and Pd(II) ions
摘要
Five new cefradine (Cef) drug complexes were synthesized by 1 : 1 chemical reactions with Ca(II), Zn(II), Fe(III), Au(III), and Pd(II) ions in alkaline methanol/distilled water media. The general formula of Cef complexes can be presented as [M(Cef)Cln]·Cly·xH2O, where (M = CaII, ZnII, FeIII, AuIII, or PdII; n = 1, 2; y = 0,1; and x = 0, 3, 7, 14). Structures and physicochemical characteristics of complexes are studied by elemental analyses, IR, Raman and UV-Vis spectra, effective magnetic moments, X-ray powder diffraction (XRD), molar conductivity, SEM and TEM methods. Cef drug acts as a tridentate ligand toward the metal ions via oxygen atoms of the carbonyl β-lactam and carboxylate groups and nitrogen of the amino group. The effective magnetic moment of the paramagnetic Fe(III) complex in the solid state was assigned to the octahedral geometric structure. Antibacterial activity of the complexes were tested against some kinds of bacteria and fungi strains. Cytotoxicity of Au(III) complex was tested on human colon carcinoma (HCT-116) and hepatocellular carcinoma cells (HepG-2) using the MTT viability test. The results demonstrated the significant cytotoxic effect compared to the other complexes.
Letters to the Editor
Synthesis of bimetallic nanoparticles based on cobalt and nickel. Effects of their composition and structure on catalytic and magnetic properties
摘要
Bimetallic core-shell nanoparticles Co@Ni and Ni@Co and CoNi alloy ones have been prepared via polyol synthesis. Comparison of morphology, magnetic, and catalytic properties of the nanoparticles have revealed that the particles structure rather than the nickel/cobalt ratio determines their catalytic activity in the model reaction of p-nitrophenol reduction into p-aminophenol.
Pseudo-topochemical synthesis of iron(0) in aqueous solution containing dispersed titanium
摘要
The reaction of iron(III) ions with dispersed titanium in aqueous solution has been studied. The Fe–Ti species thus obtained have been found to be a combination of core–shell microparticles with the titanium core coated with ultramicro- and nanosized α-Fe nuclei and an ultrathin outer iron(III) oxide layer with a developed surface.
Alkylation of CH acids with haloidalkyl-1,3-dioxolanes
摘要
Alkylation of diethyl malonate and Meldrum acid with haloalkyl-1,3-dioxolanes has afforded the substituted malonates; their decarboxylation has led to the formation of esters containing a cycloacetal fragment. Reactions of the substituted malonates with urea have yielded the corresponding substituted barbiturates. Monodecarboxylation of the obtained malonates has led to the formation of 1,3-dioxolane-carboxylates.
Reactions of phosphorylated 2,6-di-tert-butyl-4-methylidenecyclohexa-2,5-dien-1-ones with aliphatic, aromatic, and heteroaromatic thiols
摘要
The addition of alkanethiols, benzenethiol, and hetarenethiols to phosphorylated quinomethanes afforded P,S- and N,P,S-containing polyfunctional organic compounds as potential bactericidal agents.