Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).1
V. Starova, D. Khomenko, R. Doroshchuk, R. Lampeka
The development of new fluorescent reagents for determination of trace amounts of zinc in biological samples is an actual issue. Efficient reagents should characterized by high hydrophobicity, low sensitivity to media acidity and intense fluorescence in the long-wavelength region of the spectrum. Therefore, the using of a rigid π-conjugated molecule of 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole as a fluorescent probe for the determination of zinc micro-quantities in biological samples is considered as a rational choice. 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole is a highly hydrophobic ligand (logP=3.0±0.1). Dissociation of the protonated nitrogen atom in the pyridine cycle of the ligand occurs at pH = 4, рКа1= 3.98±0.05. The pKa2 value is equal to 8.74 ± 0.03 and corresponds to the dissociation of the N-H group of the triazole fragment. The absorption spectrum of the ligand solution in DMSO is characterized by two bands with maximum at 272 nm and 320 nm due to intraligand π-π * transitions. The values of the molar absorption coefficient for these bands are 1.18·104 l·mol-1·cm-1 and 1.36·104 l·mol-1·cm-1, respectively. Two bands at 402 nm and 535 nm are also observed on the fluorescence spectra of the ligand. The high fluorescence intensity in the long-wavelength region of the spectrum indicates the promising use of this ligand as an analytical reagent at a creation of new fluoresce techniques. 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole as chelating ligand can form two complex compounds in DMSO solution with composition ML and ML2. Complex formation is accompanied by the appearance of a third absorption band in the visible regions of the spectrum at 440 nm (ε440≈ 6,5·103 l·mol-1·cm-1) due to LMCT transitions. In addition, the complex formation leads to fluorescence quenching. Developed fluorescent techniques for determination of zinc quantities in a sample of hair and in a tablet of vitamins "Duovit" are characterized by satisfactory precision and accuracy. The range of zinc concentrations determining in the hair sample is 71–286 μg/g, Sr=0.033 (n=3, P=0.95). The zinc content that was found in the "Duovit" tablet is well correlated with the declared content. This indicates the good selectivity of ligand in relation to the accompanying microelements.
{"title":"3-(2-PYRIDIL)-5-(2-HYDROXYPHENYL)-1,2,4-TRIAZOL AS A REAGENT FOR FLUORIMETRIC DETERMINATION OF MICRO-AMOUNTS OF ZINC","authors":"V. Starova, D. Khomenko, R. Doroshchuk, R. Lampeka","doi":"10.17721/1728-2209.2019.1(56).1","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).1","url":null,"abstract":"The development of new fluorescent reagents for determination of trace amounts of zinc in biological samples is an actual issue. Efficient reagents should characterized by high hydrophobicity, low sensitivity to media acidity and intense fluorescence in the long-wavelength region of the spectrum. Therefore, the using of a rigid π-conjugated molecule of 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole as a fluorescent probe for the determination of zinc micro-quantities in biological samples is considered as a rational choice. 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole is a highly hydrophobic ligand (logP=3.0±0.1). Dissociation of the protonated nitrogen atom in the pyridine cycle of the ligand occurs at pH = 4, рКа1= 3.98±0.05. The pKa2 value is equal to 8.74 ± 0.03 and corresponds to the dissociation of the N-H group of the triazole fragment. The absorption spectrum of the ligand solution in DMSO is characterized by two bands with maximum at 272 nm and 320 nm due to intraligand π-π * transitions. The values of the molar absorption coefficient for these bands are 1.18·104 l·mol-1·cm-1 and 1.36·104 l·mol-1·cm-1, respectively. Two bands at 402 nm and 535 nm are also observed on the fluorescence spectra of the ligand. The high fluorescence intensity in the long-wavelength region of the spectrum indicates the promising use of this ligand as an analytical reagent at a creation of new fluoresce techniques. 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole as chelating ligand can form two complex compounds in DMSO solution with composition ML and ML2. Complex formation is accompanied by the appearance of a third absorption band in the visible regions of the spectrum at 440 nm (ε440≈ 6,5·103 l·mol-1·cm-1) due to LMCT transitions. In addition, the complex formation leads to fluorescence quenching. Developed fluorescent techniques for determination of zinc quantities in a sample of hair and in a tablet of vitamins \"Duovit\" are characterized by satisfactory precision and accuracy. The range of zinc concentrations determining in the hair sample is 71–286 μg/g, Sr=0.033 (n=3, P=0.95). The zinc content that was found in the \"Duovit\" tablet is well correlated with the declared content. This indicates the good selectivity of ligand in relation to the accompanying microelements.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"121 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76545414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).8
O. Kharchenko, V. Smokal, O. Krupka, A. Kolendo
It's known that polystyrene is one of the most widely used plastics. The materials based on it are used in almost all branches of engineering and human's daily life. Therefore, the creation of new highly effective thermal stabilizers for polystyrene remains as the actual task of polymer chemistry. Combining fragments of basic industrial monomer with the modifiers in the polymer matrix provides the ability to control performance properties of obtained materials. Investigation of thermostabilitive action of new styrylquinoline containing methacrylic monomers on polystyrene have been described in this work. Polystyrene and copolymers based on styrene and new methacrylic styrylquinoline containing monomers were synthesized by free radical thermoinitiated polymerization. 2,2´-Azo-bisisobutyronitrile (1 mass per cent) was used as initiator. Styrylquinoline monomers (3 mol per cent) were added to styrene for making modified samples. Polymerization was carried out by heating of reactants in ethyl acetate during 16 hours. Polymers were precipitated in isopropanol and dried at vacuum. The impact of such dopants – 2-[2-(4-methoxyphenyl)ethenyl]quinolin-8-yl 2-methylpropyl-2-enoate (М1), 2-(2-phenylethenyl)quinolin-8-yl 2-methylpropyl-2-enoate (М2), 2-[2-(4-nitrophenyl)ethenyl]quinolin-8-yl 2-methylpropyl-2-enoate (М3) were investigated. Thermostability of polystyrene and modified samples styrene:M1, styrene:M2, styrene:M3 were studied by dynamic thermograviametric analysis. It was shown that destruction of polystyrene with dopants M1-M2 starts at 41–42°С higher than reference polystyrene prepared at the same conditions and polystyrene of brand STYRONE (Switzerland). Sample with dopant M3 begins destruction with lower speed than reference polystyrene. First one loses 20% of weight at 347°С while reference polystyrene loses 50% of weight. It means, that dopant M3 can act as retarder of thermal destruction of polystyrene. It was found that new monomers have thermal stabilizing effect after its covalent introducing and can act as effective inhibitors of thermodestruction of polystyrene in the air.
{"title":"THERMOSTABILITY OF POLYSTYRENE BY STYRYLQUINOLINE CONTAINING METHACRYLATES","authors":"O. Kharchenko, V. Smokal, O. Krupka, A. Kolendo","doi":"10.17721/1728-2209.2019.1(56).8","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).8","url":null,"abstract":"It's known that polystyrene is one of the most widely used plastics. The materials based on it are used in almost all branches of engineering and human's daily life. Therefore, the creation of new highly effective thermal stabilizers for polystyrene remains as the actual task of polymer chemistry. Combining fragments of basic industrial monomer with the modifiers in the polymer matrix provides the ability to control performance properties of obtained materials. Investigation of thermostabilitive action of new styrylquinoline containing methacrylic monomers on polystyrene have been described in this work. Polystyrene and copolymers based on styrene and new methacrylic styrylquinoline containing monomers were synthesized by free radical thermoinitiated polymerization. 2,2´-Azo-bisisobutyronitrile (1 mass per cent) was used as initiator. Styrylquinoline monomers (3 mol per cent) were added to styrene for making modified samples. Polymerization was carried out by heating of reactants in ethyl acetate during 16 hours. Polymers were precipitated in isopropanol and dried at vacuum. The impact of such dopants – 2-[2-(4-methoxyphenyl)ethenyl]quinolin-8-yl 2-methylpropyl-2-enoate (М1), 2-(2-phenylethenyl)quinolin-8-yl 2-methylpropyl-2-enoate (М2), 2-[2-(4-nitrophenyl)ethenyl]quinolin-8-yl 2-methylpropyl-2-enoate (М3) were investigated. Thermostability of polystyrene and modified samples styrene:M1, styrene:M2, styrene:M3 were studied by dynamic thermograviametric analysis. It was shown that destruction of polystyrene with dopants M1-M2 starts at 41–42°С higher than reference polystyrene prepared at the same conditions and polystyrene of brand STYRONE (Switzerland). Sample with dopant M3 begins destruction with lower speed than reference polystyrene. First one loses 20% of weight at 347°С while reference polystyrene loses 50% of weight. It means, that dopant M3 can act as retarder of thermal destruction of polystyrene. It was found that new monomers have thermal stabilizing effect after its covalent introducing and can act as effective inhibitors of thermodestruction of polystyrene in the air.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91062003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).10
O. Kharchenko, V. Smokal, O. Krupka, A. Kolendo
Polymethylmethacrylate is widely use material in optics due to its atmosphere resistance, chemical stability, good mechanical properties, transparency and light transmission. Due to these properties, PMMA is often used as a polymeric matrix for creating photosensitive polymers and polymers with nonlinear optical (NLO) properties. Materials with NLO properties can be made by introducing moleculas of chromophores into the polymer chain. There are two fundamentally different ways of doing this. The first is to create composite material where the chromophore is a dispersed phase and is introduced into the system as a "guest". In the second case, the chromophore is introduced into the polymer chain covalently, and can be included in the side and the main chain. Studies of polymers containing NLO chromophore in the side chain have shown a number of advantages: better orientation of the chromophores under the action of an electric field; relaxation processes are much slower; increasing time and thermal stability; increasing the glass transition temperature of the polymer. Based on present knowledge we decided to design new methacrylic polymers with styrylquinoline chromophore in side chain. The polymerization ability of the new monomers for free radical homopolymerization was investigated kinetically by using dilatometric method. It was found that new 2-styrylquinoline containing monomers are able to homopolymerization with high conversions (63–83%). The polymerization was carried out in DMF using 2,2´-azobisisobutyronitrile as initiator at 80°C in argon atmosphere. The products of polymerization were characterized by 1H NMR spectroscopy. It was installed that all new monomers have bigger speed of polymerization (Ksum= 1.36–8.33×103 l/mol×s) then methylmethacrylate (Ksum= 0.5×103 l/mol×s), phenylmethacrylate (Ksum= 1.1×103 l/mol×s) and similar to polymerization of 2-methyl-8-oxyquinoline methacrylate (Ksum= 3.28×103 l/mol×s). It was found that speed of polymerization increases with increasing electron donating power of substitute in paraposition of the aromatic ring. It has been proven that presence of electron acceptor group reduces speed of polymerization.
{"title":"KINETIC'S INVESTIGATION OF METHACRYLIC MONOMERS BASED ON 2-STYRYLQUINOLINE","authors":"O. Kharchenko, V. Smokal, O. Krupka, A. Kolendo","doi":"10.17721/1728-2209.2019.1(56).10","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).10","url":null,"abstract":"Polymethylmethacrylate is widely use material in optics due to its atmosphere resistance, chemical stability, good mechanical properties, transparency and light transmission. Due to these properties, PMMA is often used as a polymeric matrix for creating photosensitive polymers and polymers with nonlinear optical (NLO) properties. Materials with NLO properties can be made by introducing moleculas of chromophores into the polymer chain. There are two fundamentally different ways of doing this. The first is to create composite material where the chromophore is a dispersed phase and is introduced into the system as a \"guest\". In the second case, the chromophore is introduced into the polymer chain covalently, and can be included in the side and the main chain. Studies of polymers containing NLO chromophore in the side chain have shown a number of advantages: better orientation of the chromophores under the action of an electric field; relaxation processes are much slower; increasing time and thermal stability; increasing the glass transition temperature of the polymer. Based on present knowledge we decided to design new methacrylic polymers with styrylquinoline chromophore in side chain. The polymerization ability of the new monomers for free radical homopolymerization was investigated kinetically by using dilatometric method. It was found that new 2-styrylquinoline containing monomers are able to homopolymerization with high conversions (63–83%). The polymerization was carried out in DMF using 2,2´-azobisisobutyronitrile as initiator at 80°C in argon atmosphere. The products of polymerization were characterized by 1H NMR spectroscopy. It was installed that all new monomers have bigger speed of polymerization (Ksum= 1.36–8.33×103 l/mol×s) then methylmethacrylate (Ksum= 0.5×103 l/mol×s), phenylmethacrylate (Ksum= 1.1×103 l/mol×s) and similar to polymerization of 2-methyl-8-oxyquinoline methacrylate (Ksum= 3.28×103 l/mol×s). It was found that speed of polymerization increases with increasing electron donating power of substitute in paraposition of the aromatic ring. It has been proven that presence of electron acceptor group reduces speed of polymerization.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"92 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86819285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).2
N. Smyk, B. Kopanytsa
A certain level of NO3- in water is necessary for the growth of algae. Most aquatic organisms can survive at relatively high nitrate levels, but concentrations higher than 0.2 mg/l cause fish diseases, eutrophication and algal bloom in aquariums. Thus, it is necessary to monitor the level of nitrates in aquarium water. When choosing the method of nitrate level analysis that will be used to develop an in-site saltwater monitor system, we should take into account several key factors, such as the threshold concentration and possible inferences, including high levels of Cl- in saltwater. Other desired criteria for the method are the need to get results in real time, low cost of production, and a way to perform the measurements in-site without the need for highly skilled personnel. The voltammetry was chosen as a method that satisfies our criteria. It is known that nitrate can be reduced quantitatively on a copper electrode. However, the copper electrode becomes poisoned after only a few minutes of use. Previous studies showed that a thin layer of copper deposited on the surface of various commonly used electrodes significantly improve the perfomance of the sensing system. This paper describes the fabrication process of voltammetric sensor and shows the advantage of using a glassy carbon electrode modified with electrodeposited copper layer to measure the concentration of nitrate in sea water. We have found that the modified sensor can be effectively used to catalyze nitrate reduction with a welldefined reduction wave with E= -1.1 V. We performed the cyclic voltammetric (CV) experiments and chose an optimal supporting electrolyte and the optimal conditions for the pretreatment. It was found that the peak current of nitrate increases with the increase of Cl- concentration and is stable in the range (2–3)⋅10-1 mol/l. The pH value from 3.5 to 6.0 does not influence the reaction on an electrode. The developed sensor was used to direct determine of nitrate in artificial seawater without of any sample preparation. Potentiometry with standard proсedure of Cl- precipitation was used to validate all the results. The values obtained by both methods were in good agreement with each other.
{"title":"MODIFIED ELECTRODE FOR NO3- DETERMINATION IN SALINE WATERS BY VOLTAMMETRY METHOD","authors":"N. Smyk, B. Kopanytsa","doi":"10.17721/1728-2209.2019.1(56).2","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).2","url":null,"abstract":"A certain level of NO3- in water is necessary for the growth of algae. Most aquatic organisms can survive at relatively high nitrate levels, but concentrations higher than 0.2 mg/l cause fish diseases, eutrophication and algal bloom in aquariums. Thus, it is necessary to monitor the level of nitrates in aquarium water. When choosing the method of nitrate level analysis that will be used to develop an in-site saltwater monitor system, we should take into account several key factors, such as the threshold concentration and possible inferences, including high levels of Cl- in saltwater. Other desired criteria for the method are the need to get results in real time, low cost of production, and a way to perform the measurements in-site without the need for highly skilled personnel. The voltammetry was chosen as a method that satisfies our criteria. It is known that nitrate can be reduced quantitatively on a copper electrode. However, the copper electrode becomes poisoned after only a few minutes of use. Previous studies showed that a thin layer of copper deposited on the surface of various commonly used electrodes significantly improve the perfomance of the sensing system. This paper describes the fabrication process of voltammetric sensor and shows the advantage of using a glassy carbon electrode modified with electrodeposited copper layer to measure the concentration of nitrate in sea water. We have found that the modified sensor can be effectively used to catalyze nitrate reduction with a welldefined reduction wave with E= -1.1 V. We performed the cyclic voltammetric (CV) experiments and chose an optimal supporting electrolyte and the optimal conditions for the pretreatment. It was found that the peak current of nitrate increases with the increase of Cl- concentration and is stable in the range (2–3)⋅10-1 mol/l. The pH value from 3.5 to 6.0 does not influence the reaction on an electrode. The developed sensor was used to direct determine of nitrate in artificial seawater without of any sample preparation. Potentiometry with standard proсedure of Cl- precipitation was used to validate all the results. The values obtained by both methods were in good agreement with each other.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77182153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).6
A number of new derivatives of o-alkoxy cinnamic acids were obtained from various coumarins by opening the lactone fragment and O-alkylation of the endocyclic Oxygen atom. The α-hetaryl-β-(2-alkoxy-5-chlorophenyl)cinnamic acids were obtained from 3-(benzothiazol-2-yl)-6-chlorocoumarin and 3-(benzimidazol-2-yl)-6-chlorocoumarin by treatment with diluted alkali followed by p-methylbenzyl chloride or dimethyl sulfate addition, respectively. A similar reaction stages (opening in aqueous alkali and alkylation of the phenolate anion) was applied to the synthetic analogues of psoralen – 5-methylfuro[3,2-g]coumarins with various substituents in the furan fragment. Thus it was possible to obtain a number of 3- and 4-substituted 3-(6-alkoxybenzofuran-5-yl)but-2-enoic acids. But in this case, the conversion of the starting furo[3,2-g]coumarins to cinnamic acid derivatives was not complete even after long time of reaction with a big excess of an alkylation agent. Therefore, the necessary step is the separation of the target acid from unreacted coumarin by dissolving the product in a saturated NaHCO3 solution. The insoluble part is a practically pure starting material, which can be recycled in the reaction; so the total yield of the product would be increased. To demonstrate the synthetic abilities of 3-(6-alkoxybenzofuran-5-yl)but-2-enoic acids these compounds were used in synthesis of amides with pharmacophore fragments: a phenethylamine derivative with an additional sulfamide group and a β-alanine derivative. The experiments showed that the 3-azolylcoumarins and furo[3,2-g]coumarins coumarin cycle's opening occurs only in aqueous alkali, and when alkylated in an organic solvent in the presence of K2CO3, the lactone fragment remains unchanged. The 7-hydroxy-6-(isocoumarin-3-yl)-4-methylcoumarin cycle turned out to be more labile. The result of alkylation of this compound with ethyl acetate of chloroacetic acid in the presence of K2CO3 depended on the nature of the aprotic solvent and the temperature of reaction. So, when this reaction was carried out in boiling acetone, only the free hydroxyl group at position 7 of coumarin was alkylated. But when the initial coumarin was heated at 100°С with an excess of an alkylating agent in DMSO, simultaneous alkylation of both the free 7-OH group and the endocyclic Oxygen atom occurred.
{"title":"CERTAIN CASES OF o-ALKOXYCINNAMIC ACIDS CREATION FROM COUMARINS IN O-ALKYLATION CONDITION","authors":"","doi":"10.17721/1728-2209.2019.1(56).6","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).6","url":null,"abstract":"A number of new derivatives of o-alkoxy cinnamic acids were obtained from various coumarins by opening the lactone fragment and O-alkylation of the endocyclic Oxygen atom. The α-hetaryl-β-(2-alkoxy-5-chlorophenyl)cinnamic acids were obtained from 3-(benzothiazol-2-yl)-6-chlorocoumarin and 3-(benzimidazol-2-yl)-6-chlorocoumarin by treatment with diluted alkali followed by p-methylbenzyl chloride or dimethyl sulfate addition, respectively. A similar reaction stages (opening in aqueous alkali and alkylation of the phenolate anion) was applied to the synthetic analogues of psoralen – 5-methylfuro[3,2-g]coumarins with various substituents in the furan fragment. Thus it was possible to obtain a number of 3- and 4-substituted 3-(6-alkoxybenzofuran-5-yl)but-2-enoic acids. But in this case, the conversion of the starting furo[3,2-g]coumarins to cinnamic acid derivatives was not complete even after long time of reaction with a big excess of an alkylation agent. Therefore, the necessary step is the separation of the target acid from unreacted coumarin by dissolving the product in a saturated NaHCO3 solution. The insoluble part is a practically pure starting material, which can be recycled in the reaction; so the total yield of the product would be increased. To demonstrate the synthetic abilities of 3-(6-alkoxybenzofuran-5-yl)but-2-enoic acids these compounds were used in synthesis of amides with pharmacophore fragments: a phenethylamine derivative with an additional sulfamide group and a β-alanine derivative. The experiments showed that the 3-azolylcoumarins and furo[3,2-g]coumarins coumarin cycle's opening occurs only in aqueous alkali, and when alkylated in an organic solvent in the presence of K2CO3, the lactone fragment remains unchanged. The 7-hydroxy-6-(isocoumarin-3-yl)-4-methylcoumarin cycle turned out to be more labile. The result of alkylation of this compound with ethyl acetate of chloroacetic acid in the presence of K2CO3 depended on the nature of the aprotic solvent and the temperature of reaction. So, when this reaction was carried out in boiling acetone, only the free hydroxyl group at position 7 of coumarin was alkylated. But when the initial coumarin was heated at 100°С with an excess of an alkylating agent in DMSO, simultaneous alkylation of both the free 7-OH group and the endocyclic Oxygen atom occurred.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90673342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).4
N. Golovata, N. Kotova, Natalia Usenko
In the present work, the Gibbs energies of mixing of liquid alloys of the Ge-Mn-Gd ternary system were determined, which was made on the basis of an analysis of published data on the thermodynamic properties of liquid alloys of boundary binary systems that form the ternary Ge-Mn-Gd, as well as on the basis of the model calculations in these binary systems. To determine the activities of the components, the Gibbs energies of mixing, and the enthalpies of mixing of liquid alloys of the Ge-Mn(Gd) systems, for which alloying process is accompanied by significant heat release, an ideal associated solution model was applied. For the melts of the Mn-Gd system, which are characterized by rather insignificant exothermic effects, a model of regular solutions was used. The surface of the Gibbs energy of mixing for the alloys of the Ge-Mn-Gd ternary system has been determined on the basis of the concentration dependences of the Gibbs energies of mixing obtained for constituent binary systems under the assumption of additivity of pair interactions using the Redlich-Kister-Muggianu method. The obtained topology of the Gibbs energy isolines projections is compared with the thermochemical properties of liquid alloys of this system that we have determined earlier. A comparative analysis of the topology of these surfaces in the Ge-Mn-Gd system led to the conclusion that the surfaces of ΔG and ΔmH monotonically decrease from the manganese-rich angle of the diagram towards the Ge-Gd side of the concentration triangle. The minimum value of the thermodynamic characteristics of mixing of the ternary liquid alloys corresponds to the composition, which coincides with the composition of the most stable intermetallic compound in the Ge-Gd system. From the course of isolines of free energies and integral enthalpies of mixing, one can also conclude about the influence of a short-range order, existed in the Ge-Mn system near the composition with a mole fraction of mangan greater than 0.7, on the properties of ternary alloys in the vicinity of this composition. Thus, the topology of isolines and the large exothermic values of the obtained thermodynamic properties allow us to make a reasonable conclusion that the strong interaction between unlike components inherent in the Ge-Gd system in the solid state is also maintained for liquid alloys of the Ge-Mn-Gd system.
{"title":"MODELING OF THERMODYNAMIC PROPERTIES OF THE MELTS OF TERNARY Ge-Mn-Gd SYSTEM","authors":"N. Golovata, N. Kotova, Natalia Usenko","doi":"10.17721/1728-2209.2019.1(56).4","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).4","url":null,"abstract":"In the present work, the Gibbs energies of mixing of liquid alloys of the Ge-Mn-Gd ternary system were determined, which was made on the basis of an analysis of published data on the thermodynamic properties of liquid alloys of boundary binary systems that form the ternary Ge-Mn-Gd, as well as on the basis of the model calculations in these binary systems. To determine the activities of the components, the Gibbs energies of mixing, and the enthalpies of mixing of liquid alloys of the Ge-Mn(Gd) systems, for which alloying process is accompanied by significant heat release, an ideal associated solution model was applied. For the melts of the Mn-Gd system, which are characterized by rather insignificant exothermic effects, a model of regular solutions was used. The surface of the Gibbs energy of mixing for the alloys of the Ge-Mn-Gd ternary system has been determined on the basis of the concentration dependences of the Gibbs energies of mixing obtained for constituent binary systems under the assumption of additivity of pair interactions using the Redlich-Kister-Muggianu method. The obtained topology of the Gibbs energy isolines projections is compared with the thermochemical properties of liquid alloys of this system that we have determined earlier. A comparative analysis of the topology of these surfaces in the Ge-Mn-Gd system led to the conclusion that the surfaces of ΔG and ΔmH monotonically decrease from the manganese-rich angle of the diagram towards the Ge-Gd side of the concentration triangle. The minimum value of the thermodynamic characteristics of mixing of the ternary liquid alloys corresponds to the composition, which coincides with the composition of the most stable intermetallic compound in the Ge-Gd system. From the course of isolines of free energies and integral enthalpies of mixing, one can also conclude about the influence of a short-range order, existed in the Ge-Mn system near the composition with a mole fraction of mangan greater than 0.7, on the properties of ternary alloys in the vicinity of this composition. Thus, the topology of isolines and the large exothermic values of the obtained thermodynamic properties allow us to make a reasonable conclusion that the strong interaction between unlike components inherent in the Ge-Gd system in the solid state is also maintained for liquid alloys of the Ge-Mn-Gd system.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86098617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).3
V. Vеrbа, O. Zaporozhets, I. Кucharenko, E. Кul'baka
Antimony and its compounds are widely used in industry, making it one of the priority pollutants of air and the aquatic environment. Excess of antimony is selectively concentrated in a thyroid gland, a liver, a spleen. The manifestation of the toxic effect of antimony is a variety of impaired functions of the human body, so the content of this element in drinking water normalizes is at the level of 5 μg/l. Recently, tellurium has also been increasingly the subject of research by analyst chemists. Tellurium is a biologically active element and its concentrations in the environment are strictly regulated. According to sanitary rules and regulations, the maximum allowable concentration of tellurium in drinking water is 0.01 mg/l. The article is devoted to the elaboration of solid-phase reagents based on the quaternary ammonium salt (QAS) immobilized on silica gel and to the development on this basis of sorption-spectrometric and visual test-methods of the determination of Sb(III) and Te(IV). The mechanism of the interaction between QAS immobilized on silica gel and the anions iodide complex of antimony and tellurium was studied. It was found that it proceeds by the ion-associative mechanism. Conditions of sorption preconcentration of anionic complexes of elements were optimized. For the quantitative sorption of antimony (III), the weight of the sorbent is 0.020 g and the volume of the solution is 25.0 ml. Under these conditions, the anionic complex is sorbed by 98%. The maximum concentration ratio is 1.25 l/g. The sorption equilibrium in the system is established in 20 minutes. For the quantitative extraction of tellurium (IV), the optimal weight of the sorbent is 0.050 g and a solution volume of 25.0 ml. Under these conditions, the degree of sorption reaches about 80%. The maximum concentration ratio is 0.4 l/g. The sorption equilibrium in the system is established in 15 minutes. The influence of foreign ions on the extraction degree of the investigated elements, and also on the magnitude of analytical signal, was studied. Sorptionspectrometric and visual test-methods of the determination of Sb(III) and Te(IV) in pharmaceutical preparation "Antimonium tartaricum" and "Tellurium Metalicum".
{"title":"SORPTION PRECONCENTRATION AND DETERMINATION OF ANTIMONY AND TELLURIUM ON MODIFIED SILICA GEL","authors":"V. Vеrbа, O. Zaporozhets, I. Кucharenko, E. Кul'baka","doi":"10.17721/1728-2209.2019.1(56).3","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).3","url":null,"abstract":"Antimony and its compounds are widely used in industry, making it one of the priority pollutants of air and the aquatic environment. Excess of antimony is selectively concentrated in a thyroid gland, a liver, a spleen. The manifestation of the toxic effect of antimony is a variety of impaired functions of the human body, so the content of this element in drinking water normalizes is at the level of 5 μg/l. Recently, tellurium has also been increasingly the subject of research by analyst chemists. Tellurium is a biologically active element and its concentrations in the environment are strictly regulated. According to sanitary rules and regulations, the maximum allowable concentration of tellurium in drinking water is 0.01 mg/l. The article is devoted to the elaboration of solid-phase reagents based on the quaternary ammonium salt (QAS) immobilized on silica gel and to the development on this basis of sorption-spectrometric and visual test-methods of the determination of Sb(III) and Te(IV). The mechanism of the interaction between QAS immobilized on silica gel and the anions iodide complex of antimony and tellurium was studied. It was found that it proceeds by the ion-associative mechanism. Conditions of sorption preconcentration of anionic complexes of elements were optimized. For the quantitative sorption of antimony (III), the weight of the sorbent is 0.020 g and the volume of the solution is 25.0 ml. Under these conditions, the anionic complex is sorbed by 98%. The maximum concentration ratio is 1.25 l/g. The sorption equilibrium in the system is established in 20 minutes. For the quantitative extraction of tellurium (IV), the optimal weight of the sorbent is 0.050 g and a solution volume of 25.0 ml. Under these conditions, the degree of sorption reaches about 80%. The maximum concentration ratio is 0.4 l/g. The sorption equilibrium in the system is established in 15 minutes. The influence of foreign ions on the extraction degree of the investigated elements, and also on the magnitude of analytical signal, was studied. Sorptionspectrometric and visual test-methods of the determination of Sb(III) and Te(IV) in pharmaceutical preparation \"Antimonium tartaricum\" and \"Tellurium Metalicum\".","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76341009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).9
V. Ovdenko, D. Vyshnevskyi, S. Studzinsky, N. Davidenko
Two new symmetric azomethine dyes capable of photoinduced isomerization were synthesized by condensing symmetric bis-aldehyde (obtained by the reaction of epichlorohydrin with 4-oxybenzaldehyde) with 4-nitroaniline and 4-chloroaniline, respectively. The yield of the target products decreases with the transition from nitro-substituted azomethine to chlorine-substituted. This is due to the greater basicity of the starting amines with nitro-substitution when increasing the acceptor force of the substituent complicates the course of the reaction. Azomethines are characterized by absorption with a maximum at 400–410 nm, which makes them sensitive to radiation with a blue component of the spectrum. The photoelectric properties of azomethines upon irradiation were investigated by the method of measuring the surface potential with the help of a Kelvin dynamic probe. The maximum value of the electric potential of the photosensitive films free surface during irradiation with white LED at I = 60 W/m2 is about 270 mV in the case of azomethine with a nitro group in the 4,4' position and about 125 mV in the case of azomethine with chlorine as a substituent. That is, the magnitude of the electric potential of the free surface decreases approximately twice during the transition from nitro substituent to chlorine. This may be explained by the fact that the photoinduced changes in azomethine with a higher acceptor substituent flow more quickly and with greater efficiency. But at the same time, the reverse changes when turning off the light are just as fast. For chlorine substituted azomethine samples, the reverse process proceeds rather slowly, which may indicate greater stability over time of the photochemically modified form in case of chlorine substitution compared to the nitro-substituted analogue. Thus, the synthesized azomethines can be used in the development of new photovoltaic media and recording media for optical information recording.
{"title":"SYNTHESIS AND PHOTOVOLTAIC PROPERTIES OF SYMMETRIC BIS-AZOMETHINES WITH ACCEPTOR SUBSTITUENTS IN THE 4,4'-POSITION","authors":"V. Ovdenko, D. Vyshnevskyi, S. Studzinsky, N. Davidenko","doi":"10.17721/1728-2209.2019.1(56).9","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).9","url":null,"abstract":"Two new symmetric azomethine dyes capable of photoinduced isomerization were synthesized by condensing symmetric bis-aldehyde (obtained by the reaction of epichlorohydrin with 4-oxybenzaldehyde) with 4-nitroaniline and 4-chloroaniline, respectively. The yield of the target products decreases with the transition from nitro-substituted azomethine to chlorine-substituted. This is due to the greater basicity of the starting amines with nitro-substitution when increasing the acceptor force of the substituent complicates the course of the reaction. Azomethines are characterized by absorption with a maximum at 400–410 nm, which makes them sensitive to radiation with a blue component of the spectrum. The photoelectric properties of azomethines upon irradiation were investigated by the method of measuring the surface potential with the help of a Kelvin dynamic probe. The maximum value of the electric potential of the photosensitive films free surface during irradiation with white LED at I = 60 W/m2 is about 270 mV in the case of azomethine with a nitro group in the 4,4' position and about 125 mV in the case of azomethine with chlorine as a substituent. That is, the magnitude of the electric potential of the free surface decreases approximately twice during the transition from nitro substituent to chlorine. This may be explained by the fact that the photoinduced changes in azomethine with a higher acceptor substituent flow more quickly and with greater efficiency. But at the same time, the reverse changes when turning off the light are just as fast. For chlorine substituted azomethine samples, the reverse process proceeds rather slowly, which may indicate greater stability over time of the photochemically modified form in case of chlorine substitution compared to the nitro-substituted analogue. Thus, the synthesized azomethines can be used in the development of new photovoltaic media and recording media for optical information recording.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84798586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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