Bulletin of Taras Shevchenko National University of Kyiv. Chemistry最新文献

{"title":"FLUORESCENCE CHARACTERISTICS OF FLUORESCEIN AND EOSIN Y SOLUTIONS IN WATER-MICELLAR SURFACTANT MEDIA","authors":"V. Klovak, L. Nechpai, Serhii Lelyushok, S. Kulichenko","doi":"10.17721/1728-2209.2020.1(57).6","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).6","url":null,"abstract":"The effect of cationic, anionic and nonionic surfactants on the fluorescence properties of fluorescein and eosin Y aqueous solutions has been investigated. It has been found that sodium dodecyl sulfate does not affect the position of the maximum wavelengths of solutions of fluorescein and eosin Y in the study of the effect of an anionic surfactant on the fluorescence emission intensity of dyes. The intensity of the signal of the dye solutions when changing the concentration of anionic surfactant changes little. As the concentration of non-ionic surfactant increases, the fluorescence emission intensity of the fluorescein solutions decreases. In contrast, with increasing concentration of Triton X-100, there is an increase in the signal intensity of solutions of more hydrophobic eosin Y with subsequent access to the \"plateau\" at СТХ-100≥5.1·10–2 mol/L. The position of the maxima fluorescence emission wavelengths for the fluorescein solutions in the 0-1.0·10–5 mol/L range of concentrations of cationic surfactant cetylpyridinium chloride remain unchanged. The position of the maxima shifts to the long-wavelength region of the spectrum at higher concentrations of CPC. The nature of the position dependence of the fluorescence emission maxima of eosin Y solutions in the presence of cationic surfactants is similar. The effect of fluorescence quenching has also been shown in the study of the influence of organic substances of cationic nature on the signal intensity of fluorescein solutions. It has been shown that the concentration dependence is linear in the (0.1–4.0)·10–1 mol/L range of isoniazid molecule concentrations. The data obtained can be implemented in the development of conditions and methods for the determination of pharmacologically active substances of cationic nature by reaction with fluorescein in medicines.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78356140","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}

{"title":"OPTICAL AND PHOTOCHEMICAL PROPERTIES OF POLYMERS BASED ON 2-(4-METHACRYOXYSTYRYL)QUINOLINE","authors":"O. Krupka, V. Smokal, O. Kharchenko, B. Derkowska-Zielinska","doi":"10.17721/1728-2209.2020.1(57).15","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).15","url":null,"abstract":"The design and synthesis of new polymer materials with controlled and predictable properties is still a challenge. Photoactive chromophore can be incorporated into a polymer in several different ways: guest-host systems, main chain polymers and side chain polymers. While none of these options are not perfect and each has its advantages and disadvantages. However, the chromophore functionalized polymers were found to be more effective due to: high concentration of the chromophores can be introduced; polymers with chromophore moiety show increased stability of poling induced SHG activity and decrease of the orientation relaxation process; absence of phase separation lessens the scattering losses; such techniques as plasma etching, optically induced index changes, laser ablation, electrical poling can be applied; multilayer phormation assists in easy integration with electronic and optical components. The principles of design of various molecular photoswitches and logical devices, in particular, those based on the photoisomerization reaction of diarylethylenes have been actively investigated in recent years. Azasubstituted diarylethylenes (DAE) styrylquinolines containing a central double bond and an endocyclic nitrogen atom, have become the subject of interest due to their ability to reversible transformations (photoisomerization and protonation). In this work, photosensitive polymers were synthesized by radical polymerization of corresponding styrylquinoline derivatives with comonomers methyl methacrylate (MMA) using asobisisobutyronitrile (AIBN) as radical initiator. We present results obtained for thin films of the methacrylic polymers incorporating styrylquinoline side-group as optically active molecule. Synthesis of 2-(4-methacryloxystyryl)quinolone and 2-(4-methacryloxystyryl)-6-methoxyquinoline was described. The polymers were obtained by free radical polymerization of methacrylic monomers in dimethylformamide with azobisisobutyronitrile as initiator. The products of polymerization were characterized and evaluated by 1HNMR, UV spectroscopy. Glass transition temperatures were characterized by DSC method. It was found 133°C, 110°C, 130°C, 112°C for P1, P1MMA, P2, P2MMA respectively. Their optical and photochemical properties as well as temperature dependence of the photoluminescence of diarylethylenes have been investigated.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82147384","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}

{"title":"STRUCTURAL AND SPECTRAL STUDIES OF THE MIXED-LIGAND CATION COMPLEX OF LANTHANUM [Lа(L)2bipy2]BPh4 WITH CARBACYLAMIDOPHOSPHATE (CAPH) TYPE LIGAND AND 2,2'-BIPYRIDINE","authors":"M. Struhatska, I. Olyshevets, V. Dyakonenko, V. Ovchynnikov, S. Shishkina, V. Amirkhanov","doi":"10.17721/1728-2209.2020.1(57).4","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).4","url":null,"abstract":"A new cationic mixed-ligand complex [Lа(L)2bipy2]BPh4 (where L-= bis(N,N'-diethylamide)(N'-trichloroacetyl)-triamidophosphate anion, bipy = 2,2'-bipyridine) has been synthesized and studied by the means of IR, 1H NMR spectroscopy, thermogravimetric and X-ray structural analyses. Low-frequency shifts of the absorption bands of the carbonyl and phosphoryl groups of phosphorylated ligand in the IR spectra of the complex compared with similar absorption bands in the spectrum of \"free\" CAPh ligand are Δν(C = O) = 117 cm–1 and Δν(P = O) = 137 cm–1. The analysis of integral signal intensity in the investigated NMR spectra of coordination compounds [Lа(L)2bipy2]BPh4 indicates the molar ratio of ligand : bipyridine : tetraphenylborate anion as a 2:2:1, which corresponds to the proposed structure of the complexes. The compound has been obtained in monocrystalline form. The structure of the complex has been determined by X-ray structural analysis, its ionic structure was proved, and the coordination of two CAPh ligands through the oxygen atoms of the carbonyl and phosphoryl groups was confirmed. Based on the structural data, it was determined that the La3+ ion is octocoordinated (surrounded by four oxygen atoms from two chelated phosphoryl ligands and four nitrogen atoms from two 2,2'-bipyridine molecules). The coordination polyhedron of central ion is interpreted as a square antiprism. Complex cations and tetraphenylborate anions are connected both by electrostatic interaction and by weak intermolecular C – H ∙∙∙ π-contacts between phenyl substituents of BPh4- and molecules of 2,2'-bipyridine. It was established by thermogravimetric analysis that the complex [Lа(L)2bipy2]BPh4 obtained is thermally stable up to a temperature of 150 °C. Significant decomposition of the complex begins at a temperature of 150 °C, occurs in one stage and most intensively continues up to 300 °C. The total weight loss is 78 %.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89910915","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}

{"title":"DETERMINATION OF ORTHOPHOSPHATE IN WATER BY SOLID-PHASE CHEMILUMINESCENT METHOD","authors":"G. Sumarokova, R. Linnik, О. Zaporozhets, L. Zinko","doi":"10.17721/1728-2209.2020.1(57).17","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).17","url":null,"abstract":"Phosphorus is one of the most important nutrients. Excessive content of its compounds in water objects leads to eutrophication, as well as reduces water quality. Methods based on the formation of molybdophosphate heteropolyacid (HPA) in an acidic medium with its subsequent reduction and spectrophotometric detection of the formed reduced \"blue\" HPA are most often used to determine phosphorus compounds. These methods are unsuitable for the analysis of waters with a phosphorus content <40 μg /L. The use of the chemiluminescent method (CL) makes it possible to increase the sensitivity of the determination, but CL detection in an acidic medium under the conditions of formation of HPA is limited by the existing indicator systems. To increase the selectivity of the method for determining the microquantities of phosphate relative to metal ions, we used an approach based on the adsorption removal of analyte with next determination using the CL method. Previous removal of phosphate from an aqueous solution in the form of reduced molybdostibiumphosphate HPA was released using batch technique in optimal conditions of its formation in the solution. Silica modified with cetyltrimethylammonium bromide was used as anion exchange adsorbent. Then the concentrate was processed with alkaline lucigenin solution and registration of the CL glow resulting from the reaction. Under optimal conditions of phosphate determination, the calibration curve is linear in the range from 3.7 to 147 μg PO43–/L with a detection limit of 0.8 μg PO43–/L. Cations K+, Na+, Fe(III), Mo(VI), NH4+ and anions Cl–, F–, HCO3–, С4Н4О62–, Asc–, NO2–, SO42–, as well as EDTA, do not interfere. Silicates (SiO32–) do not interfere with the determination of phosphate, even in 100-fold excess. Nitrates at concentrations below the average content in drinking water do not interfere with the determination. The developed technique was tested on a sample of pump room water. The technique is characterized by high sensitivity and a wide range of detectable concentrations. It is not inferior in sensitivity to flow methods using fluorescent or chemiluminescent detection.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"228 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74094875","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}

{"title":"REACTION OF PYRIDO[2,1-a]ISOINDOLE WITH З (R)- AND (S)- N-α-METHILBENZYLMALEIMIDE","authors":"T. Yegorova, B. Barnych, Z. Voitenko","doi":"10.17721/1728-2209.2020.1(57).11","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).11","url":null,"abstract":"Selective chemical reactions create new possibilities for controlled synthesis of compounds with pre-designed properties for further use in medical chemistry, material science and other fields. This is especially useful for such synthetic methodology as [4+2] cycloaddition. Current work is dedicated to study of reactions between N-chiral maleinimides with cyclic dienes based on the pyridoisoindol. Pyrido[2,1-a]isoindol turned out to be the most practical object to study the first example of asymmetric variant of the Diels-Alder reaction involving condensed isoindols. Previously, we established that this heterocyclic system, in contrast to other azino- and azoloisoindols, upon undergoing cycloaddition with non-chiral maleinimides gives only rearranged adducts of the first type. This type of compounds have also interesting stereochemistry: in solid state they have twisted double bond (twist angle 7-10°), while in solution they exist as a mixture of athropodiastereomeres due to the asymmetric Carbon atom and hindered rotation around С–С bond between exocyclic double bond and 2-(α-pyridil)phenyl fragment. Initial expectation was that chiral induction would influence the ratio of corresponding athropodiastereomeres. Calculations show that there are four possible athropodiastereomeres due to the chiral center and sterically hindered chiral axis. In case of non-chiral dienophiles, reaction results in two major diastereomeres (for our purposes marked as A and B) with 70:30 ration and two minor isomers (marked С and D respectively), the latter constituting less than 5% of the total amount. Major and minor isomers are in constant complex equilibrium, controlled via slow rotation of around corresponding С-С bond on one hand (which is the reason for athropodiastereomeres between major forms A and B, shown via NMR spectra at different temperatures), and on the other hand – fast equilibrium due to the 1,5-sigmatropic shift (cause for the minor forms C and D). Target reaction was studied under standard conditions for this rearrangement and under the kinetic control in the inert atmosphere at -80°С using TiCl4 as catalyzer. We therefore show that reaction pathway is similar to our previous examples and results in rearranged adducts of the first type. Ratio of athropodiastereomeres (both major and minor forms) is different from previous examples using non-chiral 2-substituted maleimides. Asymmetric induction spontaneously transfers from influencing the Diels-Alder reaction to influencing synchronic sigmatropic rearrangement, which is the final stage in the formation of the rearranged adduct of the first type in condensed isoindol systems.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84203500","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}

{"title":"GAS SENSITIVE SEMICONDUCTOR NANOMATERIALS FOR CREATION OF HYDROGEN SENSORS","authors":"I. Matushko, L. Oleksenko, N. Maksymovych, Galina Skolyar, O. Roik, G. Fedorenko, L. Lutsenko, Oleksandr Ripko","doi":"10.17721/1728-2209.2020.1(57).10","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).10","url":null,"abstract":"Co-precipitaion method and sol-gel technique were used to prepare semiconductor microcrystalline and nanosized SnO2/Sb2O5 and Со/SnO2/Sb2O5 (0.15 wt.% Sb) materials aimed to create high sensitive hydrogen sensors. Morphology and phase composition of the obtained samples were studied by SEM, TEM and XRD methods. It was found that microcrystalline SnO2/Sb2O5 material with particle size of 1–30 μm was obtained by a co-precipitation method and nanosized SnO2/Sb2O5 material with particle size of 5–25 μm (an average size – 12 nm) was obtained by a zol-gel method. Only cassiterite phase was detected for both microcrystalline and nanosized materials. Sensitivity measurements of the sensors were carried out with using of air-hydrogen mixtures in the concentration range of 40 – 1145 ppm Н2, and dynamic characteristics (response time and relax time) were evaluated for 40 ppm Н2 at different heater power consumptions – 0.25 and 0.35 W. To increase sensitivities of the sensors, cobalt oxide, a known catalyst for hydrogen oxidation, was added to the resulting SnO2/Sb2O5 materials. It was shown that the sensors obtained by a zol-gel method demonstrate more significant sensitivity to hydrogen concentration in comparison with the sensors obtained by a co-precipitation method. It is probably associated with a higher surface area of the nanomaterial that agrees with its smaller particles as compared with the particles of the microcrystalline material. The Co-containing sensors based on the nanosized SnO2/Sb2O5 material are established to reveal higher sensitivity to Н2 than microcrystalline Co/SnO2/Sb2O5 sensors. The Co-containing sensors based on the nanosized SnO2/Sb2O5 material were found to have better dynamic characteristics than microcrystalline Co/SnO2/Sb2O5 sensors. The sensitivities increase and the response and recovery time decrease were found for both sensor materials at increasing of the sensors heater power consumption. The obtained results can be explained with different degree of energy surface heterogeneity of the used materials. The sensor response time is determined by the time of dynamic equilibrium establishment of the hydrogen oxidation reaction on the sensor surface and the recovery time is determined by the time of desorption of the H2 oxidation reaction products (H2O) from the sensor surface. Because of the processes, the sensor with a gas sensitive layer based on the nanosized material possessing with more homogeneous structure of its surface (according to the obtained TEM data) demonstrates improved gas sensitive properties in comparison with the sensor based on the microcrystalline material. The obtained results concerning the sensitivities to H2 and the dynamic parameters of the created sensors point to possibility of effective usage of the sensors based on the nanomaterial to detect H2 in air in the practice.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"61 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90373869","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}

{"title":"FEATURES OF COMPONENT INTERACTION IN LIQUID ALLOYS OF TERNARY Al-Ge-3d-Me (Me = Mn, Fe, Ni, Cu) SYSTEMS","authors":"N. Kotova, Natalia Usenko, N. Golovata","doi":"10.17721/1728-2209.2020.1(57).9","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).9","url":null,"abstract":"The features of the component interaction in liquid alloys of ternary Al-Ge-3d-Me systems (Me = Mn, Fe, Ni, Cu) are described. A joint analysis of the concentration dependences of the enthalpies of mixing of liquid alloys previously obtained by the authors via high-temperature calorimetry, and also of the phase diagrams of the constituent binary systems was carried out. The relationship between the enthalpy values and the type of short-range ordering in liquid alloys of the studied systems was established. The visual similarity of the topology of the projections of ΔmH isolines of the Al-Ge-Fe (Ni, Cu) liquid alloys and a completely different course of the isolines of the enthalpies of mixing for the liquid Al-Ge-Mn alloys are established. The changes in the absolute values of the ΔmHmin from system to system are observed. The enthalpies are approximately the same for the Al-Ge-Mn and Al-Ge-Fe systems (about -20 kJ⋅mol-1), they increase significantly from Al-Ge-Fe to Al-Ge-Ni (-50 kJ⋅mol-1), and then decrease substantially towards the Al-Ge-Cu system (-15 kJ⋅mol-1). For the Al-Ge-Mn (Fe, Ni, Cu) liquid alloys the lines of extreme interaction are located near the 3d-corner of the concentration triangle. These lines connect the compositions of the most stable intermetallic compounds in binary Al(Ge)-Mn(Fe, Ni, Cu) systems. It has been shown that the thermodynamic properties of Al-Ge-Fe (Ni, Cu) liquid alloys are mainly determined by the pair interaction of the components of the constituent binary Al-Fe(Ni, Cu) and Ge-Fe(Ni, Cu) systems, the influence of Al-Fe(Ni, Cu) systems being prevailed. For the Al-Ge-Mn system, the interaction of components in the Ge-Mn binary system gives the main contribution to the thermodynamic properties of the ternary system. The Al-Ge-Mn (Fe, Cu) systems are characterized by significantly lower absolute values of the heats of alloy formation compared to the Al-Ge-Ni one. The specified characteristics of component interaction in the ternary systems under consideration and different values of the enthalpies of mixing are determined by the peculiarities and regular changes of the electronic structure of 3d metals across the 3d series from Mn to Cu.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84175945","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}

{"title":"REACTION OF 2-HETARYL-2-(DIHYDROFURAN-2(3H)-ILIDEN)ACETONITRILES WITH AROMATIC AMINES","authors":"R. Shemehen, O. Khilya, Y. Volovenko","doi":"10.17721/1728-2209.2020.1(57).12","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).12","url":null,"abstract":"This article reports on the reaction of 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles with aromatic amines as N-nucleophiles. 2-Hetaryl-2-(furanyl-2-ylidene)acetonitriles represent versatile building blocks in syntheses of ω-(N-aryl)alkyl substituted heterocycles due to the presence of 1,3-bielectrophilic acrylonitrile fragment functionalized with unsaturated heterocyclic ring and nucleophilic azaheterocyclic moiety. The carbonyl group masked within the N-arylpyrrolidinylidene fragment which undergoes a ring opening through the reaction with nucleophiles. So, a method for the synthesis of 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles and 2-hetaryl-2-(N-arylpyrrolidin-2-ylidene)acetonitriles has been developed by us. The proposed scheme is based on the available reagents using. As a result of Michael addition, the aromatic amines to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles followed by ring transformations has formed two types of products, depending on the reaction conditions. The reaction of substituted furanylylideneacetonitriles with aromatic amines proceeds in good to high yields affording the corresponding 3-(arylamino)hex-2-enenitriles and 2-(N-arylpyrrolidin-2-ylidene)acetonitriles derivatives. The stereochemistry of the ring-opening reaction follows the rules of a classical SN2 mechanism. The resulting linear products can be cyclized to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles in high yields by treatment with the catalytic amount of acid or the equimolar amount of aromatic amines. Under these conditions 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles arising from reaction gives the ring closure. Since both ring-opening and cyclisation occur with fixed stereochemistry the reaction appears a valuable modification to the preparation of acetonitriles derivatives.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78271802","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}

{"title":"STRUCTURE OF THE ZINC COMPLEX WITH CYCLOHEXYL AСETOACETATE","authors":"O. Shtokvysh, L. Koval, V. Dyakonenko, V. Pekhnyo","doi":"10.17721/1728-2209.2020.1(57).16","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).16","url":null,"abstract":"Binuclear complex of Zn(II) with cyclohexyl acetoacetate was obtained and structurally characterized for the first time. According to structural data, the crystal system is triclinic, space group P-1; a = 7.6530(4), b = 12.2412(8), c = 12.9102(9) Å; α = 90.198(5), β = 101.071(5), γ = 96.937(5) deg. The molecular structure corresponds to the formula [Zn2(C10H15O3)4(C2H5OH)2]. The complex is located in a special position to the symmetry center of the unit cell. The coordination polyhedrons of the Zn atoms are the same distorted octahedrons formed by six oxygen atoms. Each formed by 4 oxygen atoms in the equatorial position, which belong to three ligand molecules: terminal ligand (2 oxygen atoms) and bridged ligand (1 oxygen atom) which chelate the zinc atom of the named polyhedron and 1 oxygen atom belong to a bridged ligand that chelates the other nucleus and monodentantly coordinated to mentioned one. Two oxygen atoms occupy an axial position, one of which belongs to the terminal ligand, mentioned above and the other to the coordinated ethanol molecule. The bond between the complex nuclei is stabilized by two hydrogen bonds formed by the hydrogen atoms from hydroxyl groups of ethanol molecules and the enol oxygen atoms of the terminal ligands of the other nucleus. The compound was also characterized by IR-spectroscopy, characteristic bands (сm-1) are: ν(C–H) - 2936, 2860, ν(C=O) & ν(C=C) – 1612, ν(C=O) + δ(C–H) – 1532, ν(C=C) & ν(C-CH3)– 1252, δ(C–H) – 1172, π(C–H) – 784, ν(M–O) – 456, 416. IR spectroscopy data confirm the bidentate coordination of cyclohexyl acetoacetate to zinc atoms in deprotonated form with the formation of chelated metallocycles. The structure of the complex is similar to the structures of cobalt and nickel complexes with cyclohexyl acetoacetate. Analysis of XRD-data (which are supplemented with this work) for Co(II), Ni(II) and Zn(II) complexes with acetoacetic acid esters shows that their structure, in particular the number of metal centers in the structures, regardless of the nature of the central atom or the alcohol fragment, but determined the presence of components capable of complementing the coordination sphere of the metal in reaction media.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"653 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76838107","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}

{"title":"CATECHOLASE ACTIVITY OF A COPPER(II) COMPLEX WITH THE 2-(5-(1,2,4)TRIAZOLE-1-ILMETHYL-1H-(1,2,4)-TRIAZOLE-3-IL)-PYRIDYL","authors":"D. Khomenko, Roman O. Doroschuk, I. Odarych, I. Raspertova, R. Lampeka","doi":"10.17721/1728-2209.2020.1(57).5","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).5","url":null,"abstract":"Methods of the synthesis of 2-(5-(1,2,4)triazol-1-ylmethyl-1H-(1,2,4)-triazol-3-yl)-pyridine and a binuclear copper complex are described. The structure of the complex is established by X-ray structural analysis. The complex is a centrosymmetric [Cu2(L)2(NO3)2·2H2O]·H2O dimer. The Cu-Cu distance is 4.0408 (3) Å. In the complex the ligand is in a deprotonated state. Due to this, the triazole fragment acts as a bridge between the two metal centers. Copper ions are in an octahedral environment. The equatorial plane is formed by three triazole nitrogen atoms and one pyridyl nitrogen atom. The axial positions are occupied by a water molecule and a nitrate ion. Isotropic patterns corresponding to binuclear copper particles of the [Cu2L2-H]+ composition were registered in the ESI mass spectra of the solution of the [Cu2(L)2(NO3)2(H2O)2]·H2O complex. These data confirm the presence of a binuclear complex in solution. The catecholoxidase activity of the binuclear copper (II) complex based on 2-(5-(1,2,4)triazol-1-ylmethyl-1H-(1,2,4)-triazol-3-yl)-pyridine was studied. The kinetics of model reactions of the catecholase type were investigated by the method of initial velocities using a model substrate of 3,5-di-tert-butyl catechol (3,5-DTBK). At low concentrations of 3,5-DTBK, the dependence of the initial oxidation rate on the concentration of the substrate is linear, which corresponds to the first order of the reaction on the substrate. However, the dependence graph at higher concentrations of 3,5-DTBK is nonlinear and indicates the saturation of the catalyst with the substrate. The form of the dependence of the initial reaction rate on the substrate concentration is explained within the framework of the Michaelis-Menten model, which well describes the behavior of natural metaloenzymes.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85362473","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}