Volume 88, Nº 12 (2018)
- Ano: 2018
- Artigos: 49
- URL: https://journals.rcsi.science/1070-3632/issue/view/13704
Article
Formation and Thermal Behavior of Nanocrystalline Bi2Ti2O7
Resumo
Formation of nanocrystalline bismuth titanate Bi2Ti2O7 with pyrochlore structure obtained via thermal decomposition of a co-precipitated product has been studied. The onset of vigorous formation of Bi2Ti2O7 has been shown to correlate with the melting point of the surface phase based on bismuth oxide. The upper temperature limit of the region of nanocrystalline Bi2Ti2O7 stability has been found. Technological parameters of synthesis of Bi2Ti2O7 with average crystallite size of 75–130 nm have been determined.
Synthesis of Nanocrystalline HoFeO3 Photocatalyst via Heat Treatment of Products of Glycine-Nitrate Combustion
Resumo
Specific features of the formation of orthorhombic and hexagonal holmium orthoferrite during heat treatment of the products of glycine-nitrate combustion have been studied. Photocatalytic activity of orthorhombic nanocrystals of holmium orthoferrite in the process of photoinduced decomposition of Methyl Orange in an aqueous solution under visible light irradiation has been studied.
Borazine Thermal Decomposition in Unsaturated Vapor
Resumo
The temperature dependence of vapor pressure over liquid and solid borazine has been measured by static tensiometry method with a membrane null-manometer at 200–259 K. Gas-phase heat-induced decomposition of borazine in its unsaturated vapor has been studied over the 373–473 K range.
Study of the Kinetics of Esterification of Dichloromaleic Anhydride with Methanol in the Presence of Zeolitic Catalysts
Resumo
Kinetics and mechanism of esterification of dichloromaleic anhydride with C1–C4 alcohols in the presence of zeolitic catalysts have been studied. The stage-by-stage Langmuir–Hinshelwood mechanism of heterogeneous catalysis at acidic active surface sites of zeolites has been suggested. The kinetic model has been elaborated, the parameters of the experimental data fitting have been calculated.
Thermal Reactions of Polyfluoro-ortho-chloroarenethiols with Tetrafluoroethylene
Resumo
Co-pyrolysis of 2,5-dichloro-3,4,6-trifluorobenzenethiol, 2-chloro-4-trifluoromethyl-3,5,6-trifluorobenzenethiol, and 3-chloro-2,5,6-trifluoropyridine-4-thiol with tetrafluoroethylene has given, heptafluoro-5- chloro-2,3-dihydrobenzo[b]thiophene, 6-trifluoromethylheptafluoro-2,3-dihydrobenzo[b]thiophene, and heptafluoro- 2H,3H-thieno[2,3-c]pyridine, respectively, as the major products. The reactions of these thiols containing the chlorine atom in the ortho-position to the thiol group differ from that between 4-chloro-2,3,5,6- tetrafluorobenzenethiol and tetrafluoroethylene, the latter one giving perfluoroindane as the major product.
Properties of 2-Iodomethyl-2,3-dihydro[1,3]oxazolo[3,2-a]pyridinium Triiodide
Resumo
2-Iodomethyl-2,3-dihydro[1,3]oxazolo[3,2-a]pyridinium triiodide was synthesized by the reaction of 1-allylpyridin-2(1H)-one with hydrogen iodide in the presence of hydrogen peroxide or with iodine in acetone. The title compound reacted with palladium(II) iodide in DMSO to give crystalline bis(2-iodomethyl-2,3-dihydro[1,3]oxazolo[3,2-a]pyridinium) di-μ2-iodido-tetraiodidodipalladate(II) whose structure was proved by X-ray analysis. The reaction of 2-iodomethyl-2,3-dihydro[1,3]oxazolo[3,2-a]pyridinium triiodide with sodium iodide in acetone afforded 2-iodomethyl-2,3-dihydro[1,3]oxazolo[3,2-a]pyridinium iodide which decomposed into initial 1-allylpyridin-2(1H)-one and iodine on heating in methanol.
Synthesis and Properties of New 4-Oxo-4,5-dihydro-1,3-oxazolium Perchlorates
Resumo
D-Pantoic acid amide obtained by treatment of D-(–)-pantolactone with ammonia reacted with acetic anhydride in the presence of perchloric acid to give 5-[2-(acetoxy)-1,1-dimethylethyl]-2-methyl-4-oxo- 4,5-dihydro-1,3-oxazolium perchlorate. Reaction of the latter with aromatic aldehydes afforded 2-(2- arylethenyl)-4-oxo-4,5-dihydro-1,3-oxazolium perchlorates which showed no appreciable growth-regulating activity but clearly exhibited antidotal activity against 2,4-dichlorophenoxyacetic acid (2,4-D herbicide).
Antioxidant Activity of 2,6-Di-tert-butylphenol Derivatives in Lipid Peroxidation and Hydrogen Peroxide Decomposition by Human Erythrocytes in vitro
Resumo
1-(3,5-Di-tert-butyl-4-hydroxyphenyl)propane-1,2-dione dioxime and 3,5-di-tert-butyl-4-hydroxybenzohydrazide showed a high antioxidant efficiency in comparison to the known inhibitors 2,6-di-tertbutylphenol, 2,6-di-tert-butyl-4-mercaptophenol, and 2,6-di-tert-butyl-4-methylphenol (BHT), in model nonenzymatic human erythrocyte membrane lipid peroxidation.
Macrocyclic Receptors Based on Monosubstituted Pillar[5]arene Containing a 3,3′-Iminodipropanoic Acid Fragment
Resumo
Pillar[5]arene derivatives containing 3,3′-iminodipropanoic acid, its hydrazide, and amide fragments have been synthesized for the first time. The spectral characteristics (IR, 1H NMR) of the synthesized macrocycles have been analyzed.
Synthesis of 8-Methyl-5-[(methylsulfanyl)methyl]-3-thiabicyclo[3.3.1]non-7-en-6-one and Its Extraction Ability for Gold(III)
Resumo
An efficient one-pot procedure has been proposed for the synthesis of 8-methyl-5-[(methylsulfanyl) methyl]-3-thiabicyclo[3.3.1]non-7-en-6-one from accessible natural raw materials. A stable complex of the title compound with gold(III) has been obtained by the extraction method, and the mode of its coordination to the metal ion has been determined by IR and NMR spectroscopy.
Effect of Nitrogen-Containing Bases on Oxidation of Ferrocenylboric and Ferrocenylcarboxylic Acids with Hydrogen Peroxide in Water and Water–Acetonitrile Mixed Solvent
Resumo
The effect of triethylamine and pyridine on the kinetics and mechanism of ferrocenylboric and ferrocenylcarboxylic acids oxidation with hydrogen peroxide in water and aqueous-organic media has been studied. The addition of amines has accelerated the oxidation of ferrocenylboric acid both by hydrogen peroxide and by oxygen. Triethylamine has slowed down the oxidation of ferrocenylacetic acid and stabilized the formed zwitter-ion Fc+CH2COO–. Ferrocenylcarboxylic acid has not been oxidized by H2O2. The mechanism of the reaction has been suggested.
Chemisorption Activity of Mercury(II) Cyclopentamethylenedithiocarbamate: Synthesis, Structure, and Thermal Behavior of the [Hg2{S2CN(CH2)5}4] and [Au3{S2CN(CH2)5}6][Au{S2CN(CH2)5}2][Hg2Cl6]2 Complexes
Resumo
The dinuclear complex mercury(II) cyclopentamethylenedithiocarbamate (piperidine-1-carbodithioate) [Hg2{S2CN(CH2)5}4] was synthesized and its chemisorption activity toward a solution of AuCl3 in 2 M HCl was studied. The chemisorption of gold from the solution forms an ionic gold(III)‒mercury(II) dithiocarbamato-chlorido complex comprising three isomeric gold cations and an unsymmetrical hexachlorodimercurate anion. The structural organization and thermal behavior of the resulting compounds was studied.
Synthesis, Structure, and X-Ray Photoelectron Spectra of Cobalt and Copper Complexes with 2-{(E)-[2-(4-Hydroxybutylamino)benzimidazol-1-yl]iminomethyl}phenol
Resumo
A new azomethine compound, 2-{(E)-[2-(4-hydroxybutylamino)benzimidazol-1-yl]iminomethyl}- phenol, and its cobalt(II) and copper(II) complexes were synthesized and characterized by IR, 1Н NMR, and X-ray photoelectron spectroscopy and quantum-chemical calculations. The crystal and molecular structures of the cobalt complex were established by X-ray diffraction analysis. The oxidation state of the cobalt ion in the complex after its crystallization from the solution was defined more exactly by X-ray photoelectron spectroscopy.
Synthesis and Spectral Characteristics of Sn(IV) Tetraphenylporphyrinates
Resumo
Coordination reactions of 5,10,15,20-tetraphenylporphyrin, 2-bromo-5,10,15,20-tetraphenylporphyrin, 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin, 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin and metal-exchange reactions of their cadmium complexes with tin(II) chloride in dimethylformamide are described. Optimum conditions for the synthesis of Sn(IV) tetraphenylporphyrinates have been elaborated. The obtained substances have been identified by electron absorption spectroscopy, 1H NMR spectroscopy, and mass-spectroscopy.
Synthesis of Mesomorphic Derivatives of Methyl 2,4-Dihydroxybenzoate and Spectral and Luminescence Properties of Their Lanthanide Complexes
Resumo
The derivatives of methyl 2,4-dihydroxybenzoate containing fragments of different organic acids in position 4 have been synthesized. Their mesomorphic properties have been investigated. Lanthanide complexes of the prepared compounds have been obtained. Their spectral properties have been studied.
Reaction of Arabinogalactan Modified by Salicylic and 4-Aminobenzoic Acids with Iodine
Resumo
The regularities of the reactions in arabinogalactan–salicylic (and/or 4-aminobenzoic) acid–iodine systems in aqueous solutions were studied by spectral methods. The compositions of the complexes and their stability constants were determined and the standard thermodynamic parameters of complex formation (ΔHº, ΔGº, ΔSº) were estimated. It was shown that the modification of arabinogalactan by a drug compound stabilizes the complexes and increases the iodine concentration in them. The synthesized compounds were found to exhibit a high bactericidal activity.
Scheme of the Complex Formation of DNA Telomeric Sequence with TMPyP4 Porphyrine
Resumo
The model of the complex formation in a DNA oligonucleotide solution in the presence of TMPyP4 porphyrine has been recognized using a matrix method basing on the experimentally observed composition-property features. The experimental data on UV spectroscopic titration of G4 Tel22 oligonucleotide by TMPyP4 porphyrine have been interpreted in terms of equilibrium complex formation of the ligand with the macromolecule at four independent binding sites (coordination vacancies). The suggested matrix model has considered the mutual influence of the ligands bound at each of the Tel22 coordination vacancies. Sequential attachment of the TMPyP4 ligand to the Tel22(TMPyP4)n complex has affected the shape of the UV absorption spectrum of the earlier bound ligands. The cross-validation of the conventional stepwise complex formation model and the matrix binding model has confirmed the validity of the new interpretation.
Features of Thermal Oxidation of Polyacylonitrile in the Presence of Carbon Nanotubes
Resumo
Chemical transformations in the course of heat treatment of polyacrylonitrile films containing highly dispersed multiwalled carbon nanotubes have been analyzed. It has been shown that the introduction of the nanotubes results in the cyclization reaction completeness at lower temperature in comparison of the pristine polyacrylonitrile, and the formed product has more regular structure.
Facile Catalyst-Free Synthesis of New Functionalized 1H-Pyrazolo[1,2-b]phthalazines
Resumo
Some new derivatives of 3-amino-1-aryl-N-butyl-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]- phthalazine-2-carboxamide are synthesized via in situ Knoevenagel condensation of aromatic aldehydes with N-butyl-2-cyanoacetamide, which leads to 3-aryl-N-butyl-2-cyanoacrylamides. This is followed by the reaction with phthalhydrazide upon refluxing in ethanol under catalyst-free conditions. The products are characterized on the basis of IR, 1H and 13C NMR spectral data.
Synthesis, Biological Evaluation, and Molecular Docking of 1,4-Benzodioxan Derivatives as Potential Antibacterial Agents
Resumo
A series of novel 1,4-benzodioxan derivatives containing Schiff base are synthesized by the method of splicing active substructures. All compounds are assayed for antimicrobial activity. The preliminary results indicate that most of the products demonstrate higher antibacterial activity against Gram-negative bacteria strains than Gram-positive bacteria strains. Compounds 4d and 4m exhibit better antibacterial activity against E. coli (MIC = 0.78 and 0.17 μg/mL), respectively; compound 4g displays better antibacterial activity against P. aeruginosa (MIC = 0.78 μg/mL). Eleven common antibacterial targets are selected for molecular docking of target compounds. The results demonstrate that all target compounds have the strongest binding energy to Tyrosine-tRNA synthetase (-CDOCKER_INTERACTION_ENERGY, kcal/mol: 47.1486 and 47.3776). Therefore, it is speculated that the target compounds can be used as novel tyrosine-tRNA synthetase inhibitors.
Novel Bis(1,2,4-oxadiazolyl) Fused Thiazole Derivatives: Synthesis and Anticancer Activity
Resumo
A novel series of bis-1,2,4-oxadiazole fused benzothiazole derivatives 9a–9j are synthesized, and their structures are confirmed by 1H and 13C NMR, and mass spectral data. All products are evaluated in vitro for their anticancer potential against a panel of four human cancer cell lines such as lung cancer (A549), breast carcinoma (MCF-7), melanoma (A375), and colon cancer (HT-29). The combretastatin-A4 is used as standard drug. All compounds 9a–9j exhibit significant anticancer activity with IC50 values ranging from 0.11±0.01 to 14.6±3.89 μM. Among these, compounds 9a–9d, 9h, 9i demonstrate more potent activity than the control.
Synthesis, Antioxidant, and Antileishmanial Activities of New Bis-N-amino Triazole Derivatives
Resumo
Synthesis of new bis-N-imino triazole derivatives containing oxadiazole 2, its Mannich base 3, and the S-alkyl group 4 is presented. Bis-N-iminotriazole 2 is formed in the reaction of compound 1 with terephthalaldehyde. Bis N-iminotriazole derivatives containing Mannich base 3 are synthesized by the reaction of morpholine or piperidine with the compound 2. The compound 2 also reacts with alkyl halides (butyl, pentyl, hexyl, heptyl) to give S-alkylated bis-N-imino triazoles 4. Structures of the new compounds are characterized by IR, 1H, and 13C NMR, and mass spectral data. Antioxidant (FRAP and DPPH assay) and antileishmanial activities tests of the compounds indicate that the products 2, 3a, and 3b demonstrate moderate antioxidant activity in both DPPH and FRAP assays. The antileishmanial tests indicate high activity of the compounds 3a and 3b.
Comparative Studies on DNA Binding, Photocleavage, and Photophysical Properties of Ru(II) Complexes Containing TIP {TIP = 2-(Thiophen-2-yl)-1H-imidazo[4,5-f][1,10]-phenanthroline} Ligand
Resumo
A thiophene contained imidazo phenanthroline ligand TIP {TIP = 2-(thiophen-2-yl)-1H-imidazo-[4,5-f][1,10]phenanthroline{ and its mononuclear Ru(II) polypyridyl complexes [Ru(phen)2TIP]2+ (1) (phen = 1,10-phenanthrolene) and [Ru(bpy)2TIP]2+ (2) (bpy = 2,2'-bipyridyl), are synthesized and characterized by UVVis, IR, 1H and 13C NMR, and ESI-MS spectra. Interaction of these complexes with CT-DNA is studied using UV-Vis and florescence spectra, viscosity measurements and molecular docking studies. The latter supports binding ability of complexes with stability constants deduced from UV-Vis and florescence spectra. The studies reveal that both Ru(II) polypyridyl complexes bind to DNA predominantly by intercalation, and the binding constant of complex 1 is greater than that of complex 2. Complexes 1 and 2 cleave the pBR 322 DNA under UV light.
Synthesis, Antimicrobial, and Antioxidant Studies of Some New Indolo[3,2-c]isoquinoline Derivatives
Resumo
As a part of systematic study, new series of 6-{[5-(5-substituted 2-phenyl-1H-indol-3-yl)- methyleneamino]-1,3,4-oxadiazol-2-yl}-8-substituted-6H-indolo[3,2-c]isoquinolin-5(11H)-ones and their derivatives are synthesized and evaluated for their biological activities. Compound 8a displays potent antimicrobial activity against bacteria E. coli, K. penumoniae, and S. aureus, and fungi A. niger, A. flavus, and A. fumigates. Compounds 7a and 8a demonstrate promising radical scavenging and chelating with ferrous ions (Fe2+). According to the accumulated data the designed motifs exhibit higher biological activities than the reference compounds.
1,3,4-Triarylpyrazoles Containing 2-Thioxoimidazolidinones and Different Fused Systems: Synthesis and Antimicrobial Activity
Resumo
A group of new analogs of 1,3,4-trisubstituted pyrazoles functionalized 2-thioxoimidazolidinones and fused heterocyclic systems are synthesized. Their tests of antimicrobial activity against several bacterial and fungal strains indicated relatively high activity. The composition of the novel products was elucidated from spectroscopic data.
Synthesis and Anticancer Activity of 1,2,4-Oxadiazol Linked Benzimidazole Derivatives
Resumo
A new series of 1,2,4-oxadiazole linked benzimidazole derivatives 11a–11j are synthesized. Their structures are confirmed by 1H and 13C NMR and mass spectral data. The products are tested for their anticancer activity against three human cancer cell lines, MCF-7 (breast), A549 (lung), and A375 (melanoma). The compounds 11b, 11c, 11g, and 11h are determined to be more potent than the control (MCF-7).
Efficient Synthesis of New Pyrimido[5′,4′:5,6]pyrano[2,3-d]pyrimidine-2,4,6(1H,3H)-triones via the Tandem Intramolecular Pinner–Dimroth Rearrangement, and Their Antibacterial Activity
Resumo
Synthesis of new 8-alkyl-5-aryl-1,3-dimethyl-5,7-dihydro-2H-pyrimido[5′,4′:5,6]pyrano[2,3-d]- pyrimidine-2,4,6(1H,3H)-triones by the high yield reaction of 7-amino-5-aryl-1,3-dimethyl-2,4-dioxo-1,3,4,5- tetrahydro-2H-pyrano[2,3-d]pyrimidine-6-carbonitriles with aliphatic carboxylic acids in the presence of POCl3 is presented. It is probable that synthesis of these new products proceeds via the tandem intramolecular Pinner–Dimroth rearrangement. The products are characterized by FT-IR, 1H, and 13C NMR spectra and evaluated for their antibacterial activity against gram +ve bacteria (Staphylococcus aureus and Staphylococcus epidermidis) and gram–ve bacteria (Escherichia coli and Pseudomonas aeruginosa) using the disc diffusion method.
Pyran Derivatives: Anti-Breast Cancer Activity and Docking Study
Resumo
Four novel pyran derivatives 1–4 are synthesized and characterized by IR, 1H NMR, HRMS, and single crystal X-ray data. Anticancer activity of the compounds is tested against four human breast cancer cells (HCC1937, HCC70, MDA-MB-436, and BT474) by MTT assay. Molecular docking study supports the biological assay data and suggests that compound 2 has a potential as an anticancer agent.
Synthesis and Antibacterial Evaluation of Benzofuran Based 3,5-Disubstituted Isoxazoles
Resumo
A series of novel benzofuran-isoxazole 7a–7j hybrid heterocyclic molecules are synthesized. The structures of compounds 7a–7j are assessed by IR, NMR, MASS spectroscopy and elemental analysis. The target compounds 7a–7j are screened for their antibacterial activity and demonstrated excellent to moderate activity against gram-positive and gram-negative bacteria.
Synthesis, Characterization, and Anticancer Activity of Some Thiazole and Imidazolidine Derivatives Containing Pyridine Moiety
Resumo
5-Phenyl-2-[(6-acetylpyridine-2-ylethylidene)hydrazino]thiazole 4 and 1-[(6-acetylpyrid-ine-2-ylethylidene)amino]-2-thioxoimidazolidine-4-one 6 are synthesized by cyclization of 1-[1-(6-acetylpyridin-2- yl)ethylidene]thiosemicarbazide 2 with phenacyl(ω)bromide or ethyl chloroacetate in the presence of fused sodium acetate. Reaction of compounds 2, 4, and 6 with acetic anhydride gives N-triacetyl derivative 3 and N-acetyl derivatives 5 and 7. Treatment of compound 6 with 4-methoxy benzaldehyde yields the corresponding carbanol derivative 8. Structures of the synthesized heterocyclic compounds are characterized by EI-MS and NMR spectroscopy. Antitumor activity of compounds 4, 6, 8, and 9 is evaluated against human breast carcinoma cell line (MCF-7).
Solvent Free Synthesis of N-Substituted Pyrrole Derivatives Catalyzed by Silica Sulfuric Acid
Resumo
Sulfuric acid immobilized on silica gel is used as an efficient catalyst in the synthesis of N-substituted pyrrole derivatives by the Clauson–Kaas pyrrole synthesis. The solvent free reaction mixture is stirred by grinding. Within very short reaction time the process leads to the corresponding products without any decomposition recorded.
Miniature Nanostructured Power Sources on the Basis of Direct Nuclear Energy Conversion
Resumo
Tiny nanostructured high-energy power sources based on the direct conversion of nuclear energy to electricity are developed for power supply of microelectronic and micromechanical devices, as well as remote objects. The role of energy converters in such power sources is played by metal–insulator–metal (MIM) structures with a characteristic layer thickness of 10–100 nm, and highly thermodynamically stable and radiation resistant asymmetric supercapacitors comprising a nanostructured carbon electrode and an inorganic electrolyte possessing high thermodynamic and radiation resistance are applied for energy accumulation. The predicted autonomous operation time of the power sources is not less than 20 years, specific energy is 103 kWh/kg, and capacity is not less than 1 kWh/kg.
Monolayers of Supramolecular Cryptate Complexes at the Electrode/Solution Interface
Resumo
The results of investigation of the electrochemical properties of cryptand 222 from the macropolycyclic ligands group and its complexes with cations were summarized. Emphasis was placed on the properties of the adsorbed layers of these substances at the electrode/solution interface. Adsorption parameters of the compounds studied were calculated in the framework of the Frumkin–Damaskin theory of adsorption of organic substances using the regression analysis. Comparative analysis of the data obtained was carried out.
Formazan-Containing Solid-Phase Reagent Indicator Systems for Environmental Analysis
Resumo
Research results on synthesis and application of solid-phase reagents containing formazan groups were considered. The influence of the composition and structure of immobilized organic ligands on the sorption and analytical properties of the test-tools obtained were discussed. Data on the chromogenic properties of formazan-containing analytical systems suitable for rapid testing of toxic elements in environmental samples were presented.
Comprehensive Research on the Response of MIS Sensors of Pd‒SiO2‒Si and Pd‒Ta2O5‒SiO2‒Si Structures to Various Gases in Air
Resumo
The response Pd–SiO2–Si and Pd–Ta2O5–SiO2–Si metal‒insulator‒semiconductor (MIS) sensors to H2, H2S, NO2, C2H5SH, NH3, and Cl2 in air was studied. The static and dynamic characteristics of the MIS sensors were obtained. The minimum detectable concentrations of the test gases were determined. It is shown that the MIS sensors are highly sensitive to the studied gases.
Dynamics of the Remote and Contact Interaction of Liquid Droplets with Film-Like and Fibrous-Porous Polymeric Materials
Resumo
The problem of inkjet printing quality was considered for the case of synthetic polymer-based film-like and fibrous-porous materials. Physical modeling of inkjet printing on polypropylene using water-based ink revealed remote interaction of liquid droplets with films and nonwoven webs, responsible for the droplet path deviation from the vertical fall and the droplet moving across the polymer film surface after the contact or holding at the fiber ends. Relationships were established and controlling techniques were proposed for the processes of absorption and spreading of liquid droplets in the materials to be printed with the view of increasing the accuracy of printing information symbols and reducing ink consumption.
Photoelectrochromic Organic Systems
Resumo
The electrochemical properties of photochromic compounds from the classes of diarylethenes, fulgides, quinones, spiropyrans, and dihydropyrenes exhibiting photoelectrochromic properties were analyzed for the first time. It was demonstrated that, depending on the structure and on the nature of the substituents, these compounds can exhibit electrochromic transformations under reversible oxidation of both the initial and photoinduced forms. Photochromic and electrochromic properties displayed by a number of organic compounds make them promising candidates for development of new dual-mode photo- and electrocontrolled switches for various applications.
A Multifunctional Photochromic Light-Modulating Polymer Film
Resumo
The results of the authors’ studies on development of a multilayer photochromic sun-protective energy-saving polymer film able of reversibly changing its light transmission depending on the intensity of the activating irradiation and of permanently reflecting thermal radiation were analyzed.
Photochromic Systems with Dynamic Adaptive Photobleaching
Resumo
Results of own investigations on photochromic systems bleaching reversibly under sun light depending on the intensity of excitant radiation are described. The results are aimed to be used for the development of camouflage coatings and civil cloths with photoinduced dynamic automatic color change.
Photocurable and Thermosetting Polymer Materials on the Basis of Benzocyclobutene and Its Derivatives for Electronics
Resumo
One of the promising directions, which have already been applied in many technological processes in manufacturing electronic components and devices, is the use of organic polymer materials. Continuous improvement of electronics and widening the scope of its application has led to strengthening of the requirements to materials used in its production. Polymer materials must possess a set of properties providing efficiency, reliability, and longevity of such devices. Such requirements include thermal stability at temperatures of up to 300–400°C, dielectric properties, optical transparency in the UV, visible, and near-IR ranges, chemical stability, etc. This review article covers the available information on existing polymer materials on the basis of benzocyclobutene and its derivatives, and their physicochemical properties. Comparative evaluation of materials on the basis of benzocyclobutene and its derivatives, including analogs, is made, and their application in electronic devices is described.
Principal Regularities of the Aging Behavior of Glass-Filled Polyamides
Resumo
The results of research on the aging of glass-filled polycaproamide materials are reviewed. The data on the influence of the type and concentration of glass fillers, stabilizers, and modifiers of different chemical structures, used in the manufacture of glass-filled polyamides, on the formation of the supramolecular structure of polyamides and porous structure of complex composites are summarized. Irreversible changes in the performance and mechanical properties of glass-filled polyamides are shown to be caused by damage accumulation on the glass-fiber–polyamide interface. This damage manifests itself in an increase in the volume and surface area of pores and a decrease in their average size due to crystallization and re-crystallization processes, which occur during initial storage time (1–3 years) and involve changes in crystallinity and ratio between different crystallinity forms in polyamide-6, as well as due to seasonal and daily temperature changes during further storage periods. A strong impact of storage conditions (temperature and humidity) on the level of polymer degradation and structural transformations is revealed. The mechanism of humidity (as a climatic factor) effect is established. A change of the relaxation mechanism at temperatures above 140°C (transition from the kinetic to diffusion region) is demonstrated. The main fields of practical application of the results presented in this paper are outlined.
Letters to the Editor
Bis(tetrahydro-2H-pyran-2-ylmethyl)sulfide and -Sulfoxide from Sulfur Dichloride and 5-Hexen-1-ol
Resumo
The reaction of sulfur dichloride with 5-hexen-1-ol has given bis(tetrahydro-2H-pyran-2-ylmethyl)-sulfide in 87% yield. Oxidation of the latter with NaIO4 has afforded bis(tetrahydro-2H-pyran-2-ylmethyl)-sulfoxide in 96% yield.
Novel Reactions of Tropylium Salts with Heterocyclic Diamines
Resumo
The reactions of tropylium salts with 2,5-diamino-1,3,4-thiadiazol, 3,5-diamino-1,2,4-thiadiazol, and 2,6-diaminopyridine have given novel products of substitution of hydrogen atoms of two amino groups in thiadiazols and of hydrogen atoms at С3 and С5 positions in 2,6-diaminopyridine.