Pub Date : 2023-01-01DOI: 10.31489/2959-0663/1-23-9
Namita S. Surve, Asha B. Thomas, R. Bhole, Chyandrajyoti Y. Patil
Flash chromatography and Semi-Preparative High Performance Liquid Chromatography have showed them-selves as promising separation tools. These techniques assist in the process of isolation, fractionation and pu-rification of chemical, biological and pharmaceutical substances. The present article describes the recent ad-vancements made in flash chromatography and semi-preparative HPLC techniques in the last decade with specific focus on natural products. This article highlights the basics, instrumentation, current advancements made to facilitate the separation, advantages and applications of these two techniques. Flash chromatography is a versatile tool for the rapid but efficient separation and purification of analytes in relatively pure form. Nowadays, there are even functionalized silica pre-packed cartridges with different silica weights and particle sizes that are available to use. Flash separation using dual columns can be used to enhance separation of com-plex mixtures and can be applied to numerous classes of compounds. The semi-preparative techniques, de-spite their high cost, can be helpful in high purity separation and production of reference standards for the pharmaceutical industry. This comprehensive review presents a brief analysis of all the recent research em-ploying these two techniques for varied applications. This review will help chromatography specialists to make the decision of applying these two techniques in order to accelerate their research and development journey.
{"title":"Flash Chromatography and Semi-Preparative HPLC: Review on the Applications and Recent Advancements over the Last Decade","authors":"Namita S. Surve, Asha B. Thomas, R. Bhole, Chyandrajyoti Y. Patil","doi":"10.31489/2959-0663/1-23-9","DOIUrl":"https://doi.org/10.31489/2959-0663/1-23-9","url":null,"abstract":"Flash chromatography and Semi-Preparative High Performance Liquid Chromatography have showed them-selves as promising separation tools. These techniques assist in the process of isolation, fractionation and pu-rification of chemical, biological and pharmaceutical substances. The present article describes the recent ad-vancements made in flash chromatography and semi-preparative HPLC techniques in the last decade with specific focus on natural products. This article highlights the basics, instrumentation, current advancements made to facilitate the separation, advantages and applications of these two techniques. Flash chromatography is a versatile tool for the rapid but efficient separation and purification of analytes in relatively pure form. Nowadays, there are even functionalized silica pre-packed cartridges with different silica weights and particle sizes that are available to use. Flash separation using dual columns can be used to enhance separation of com-plex mixtures and can be applied to numerous classes of compounds. The semi-preparative techniques, de-spite their high cost, can be helpful in high purity separation and production of reference standards for the pharmaceutical industry. This comprehensive review presents a brief analysis of all the recent research em-ploying these two techniques for varied applications. This review will help chromatography specialists to make the decision of applying these two techniques in order to accelerate their research and development journey.","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73699689","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 : 2023-01-01DOI: 10.31489/2959-0663/1-23-10
G. Burkeyeva, A. Kovaleva, Y. Tazhbayev, Zhansaya M. Ibrayeva, J. Plocek
The possibility of using the polymeric matrix obtained as a result of “cold” polymerization of polypropylene glycol fumarate (p-PGF) with methacrylic acid (MAA) as a polymeric base for obtaining new adhesives of domestic production was demonstrated. The starting reagent (p-PGF) was synthesized by condensation polymerization of fumaric acid with propylene glycol in the presence of a catalyst, which reduced the temper-ature and shortened the process time. A number of solutions of p-PGF in MAA of different mass composi-tions were obtained and their rheological properties were determined. Curing of the studied solutions was car-ried out by radical polymerization at room temperature in the presence of the “cold curing” initiating system. The optimum composition and amount of components of the “cold” curing initiating system consisting of an initiator (benzoyl peroxide) and a promoter (dimethylaniline) were established. Technological parameters of curing (temperature, lifetime and curing time, the value of volume shrinkage) were determined. The obtained compounds were identified by infrared spectroscopy. The surface morphology of the cured samples was stud-ied by scanning electron microscopy. It was found that varying the composition of the initial polymer-monomer mixture allows controlling the physicochemical properties.
{"title":"Development of Energy-Efficient “Cold” Curing Method for Polypropylene Glycol Fumarate Using an Optimized Initiating System","authors":"G. Burkeyeva, A. Kovaleva, Y. Tazhbayev, Zhansaya M. Ibrayeva, J. Plocek","doi":"10.31489/2959-0663/1-23-10","DOIUrl":"https://doi.org/10.31489/2959-0663/1-23-10","url":null,"abstract":"The possibility of using the polymeric matrix obtained as a result of “cold” polymerization of polypropylene glycol fumarate (p-PGF) with methacrylic acid (MAA) as a polymeric base for obtaining new adhesives of domestic production was demonstrated. The starting reagent (p-PGF) was synthesized by condensation polymerization of fumaric acid with propylene glycol in the presence of a catalyst, which reduced the temper-ature and shortened the process time. A number of solutions of p-PGF in MAA of different mass composi-tions were obtained and their rheological properties were determined. Curing of the studied solutions was car-ried out by radical polymerization at room temperature in the presence of the “cold curing” initiating system. The optimum composition and amount of components of the “cold” curing initiating system consisting of an initiator (benzoyl peroxide) and a promoter (dimethylaniline) were established. Technological parameters of curing (temperature, lifetime and curing time, the value of volume shrinkage) were determined. The obtained compounds were identified by infrared spectroscopy. The surface morphology of the cured samples was stud-ied by scanning electron microscopy. It was found that varying the composition of the initial polymer-monomer mixture allows controlling the physicochemical properties.","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"0510 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83011464","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 : 2023-01-01DOI: 10.31489/2959-0663/3-23-1
Arstan M. Gazaliyev, N. Ivanova
This year, the famous scientist and organizer of science and education in Kazakhstan, Academician of the Na-tional Academy of Sciences of the Republic of Kazakhstan Z.M. Muldakhmetov turns 90 years old. His sci-entific activity is closely connected with such branches of the theory of the structure of matter as molecular spectroscopy and quantum chemistry. His path in science reflects the history of the development of these sci-entific disciplines. The article gives a brief description of the creation of a scientific school of quantum chem-istry in Kazakhstan with the direct participation of Z.M. Muldakhmetov.
{"title":"Z.M. Muldakhmetov — a Creator of the Scientific School of Quantum Chemistry in Kazakhstan","authors":"Arstan M. Gazaliyev, N. Ivanova","doi":"10.31489/2959-0663/3-23-1","DOIUrl":"https://doi.org/10.31489/2959-0663/3-23-1","url":null,"abstract":"This year, the famous scientist and organizer of science and education in Kazakhstan, Academician of the Na-tional Academy of Sciences of the Republic of Kazakhstan Z.M. Muldakhmetov turns 90 years old. His sci-entific activity is closely connected with such branches of the theory of the structure of matter as molecular spectroscopy and quantum chemistry. His path in science reflects the history of the development of these sci-entific disciplines. The article gives a brief description of the creation of a scientific school of quantum chem-istry in Kazakhstan with the direct participation of Z.M. Muldakhmetov.","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"20 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90416546","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 : 2023-01-01DOI: 10.31489/2959-0663/2-23-9
O. V. Ponomarenko, S. Panshina, A. Bakibaev, Rahmetulla Sh. Erkasov, Madina S. Kenzhebaj, Anel' S. Montaeva
In the chemistry of heterocyclic compounds, bicyclic bisureas — glycolurils, have a special place. Glycolurils are used as a basis for the industrial production of substances that have found application in many areas of human life. The variety of glycoluril derivatives and their properties is primarily due to various substituents in the bicyclic structure. In this review, 2,4,6,8-tetraazabicyclo[3.3.0.]octane-3,7-dione (glycoluril), as the main representative of bicyclic bisureas, its physico-chemical properties, and methods for the synthesis of deriva-tives based on it are considered. In particular, the main physico-chemical characteristics of glycoluril and the data obtained from its spectral analysis by IR, NMR spectroscopy and X-ray diffraction analysis are present-ed and discussed. The paper briefly outlines the known methods for the synthesis of glycolurils and related compounds, also highlights the chemical properties of glycoluril and its derivatives, as well as ways to modi-fy them. Coordination compounds based on N-alkylglycolurils as ligands are briefly considered. The reaction products of N-halogenation and N-acylation of glycolurils are presented and discussed. Reactions for obtain-ing phosphorus-, nitro- and nitroso derivatives of glycolurils; alkylation methods, Mannich reactions, thionization, alkaline hydrolysis and reduction reactions at the carbonyl group of glycolurils are also shown. There is a discussion of the macromolecules formation in the condensation reaction of glycoluril with formal-dehyde as precursors for the synthesis of cucurbit[n]urils.
{"title":"Glycoluril and Its Chemical Properties","authors":"O. V. Ponomarenko, S. Panshina, A. Bakibaev, Rahmetulla Sh. Erkasov, Madina S. Kenzhebaj, Anel' S. Montaeva","doi":"10.31489/2959-0663/2-23-9","DOIUrl":"https://doi.org/10.31489/2959-0663/2-23-9","url":null,"abstract":"In the chemistry of heterocyclic compounds, bicyclic bisureas — glycolurils, have a special place. Glycolurils are used as a basis for the industrial production of substances that have found application in many areas of human life. The variety of glycoluril derivatives and their properties is primarily due to various substituents in the bicyclic structure. In this review, 2,4,6,8-tetraazabicyclo[3.3.0.]octane-3,7-dione (glycoluril), as the main representative of bicyclic bisureas, its physico-chemical properties, and methods for the synthesis of deriva-tives based on it are considered. In particular, the main physico-chemical characteristics of glycoluril and the data obtained from its spectral analysis by IR, NMR spectroscopy and X-ray diffraction analysis are present-ed and discussed. The paper briefly outlines the known methods for the synthesis of glycolurils and related compounds, also highlights the chemical properties of glycoluril and its derivatives, as well as ways to modi-fy them. Coordination compounds based on N-alkylglycolurils as ligands are briefly considered. The reaction products of N-halogenation and N-acylation of glycolurils are presented and discussed. Reactions for obtain-ing phosphorus-, nitro- and nitroso derivatives of glycolurils; alkylation methods, Mannich reactions, thionization, alkaline hydrolysis and reduction reactions at the carbonyl group of glycolurils are also shown. There is a discussion of the macromolecules formation in the condensation reaction of glycoluril with formal-dehyde as precursors for the synthesis of cucurbit[n]urils.","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85529662","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 : 2023-01-01DOI: 10.31489/2959-0663/3-23-2
I. Irgibaeva, V. Minaeva
The article highlights the main periods of life, scientific and pedagogical activity of Boris Fillipovich Minaev: Doctor of Chemical Sciences, Professor, Academician of the Academy of Sciences of the Higher School of Ukraine, Honored Worker of Science and Technology of Ukraine. The article reflects Minaev's great contri-bution to scientific research and informs about his achievements in the field of physical organic chemistry and molecular electronics. At the end of this article an overview of his most important scientific papers is pre-sented.
{"title":"Professor Boris Filippovich Minaev: More than Half a Century of Scientific Activity and the 80th Anniversary of His Birth","authors":"I. Irgibaeva, V. Minaeva","doi":"10.31489/2959-0663/3-23-2","DOIUrl":"https://doi.org/10.31489/2959-0663/3-23-2","url":null,"abstract":"The article highlights the main periods of life, scientific and pedagogical activity of Boris Fillipovich Minaev: Doctor of Chemical Sciences, Professor, Academician of the Academy of Sciences of the Higher School of Ukraine, Honored Worker of Science and Technology of Ukraine. The article reflects Minaev's great contri-bution to scientific research and informs about his achievements in the field of physical organic chemistry and molecular electronics. At the end of this article an overview of his most important scientific papers is pre-sented.","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"96 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78591080","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 : 2023-01-01DOI: 10.31489/2959-0663/3-23-5
S. Beznosyuk
The article analyzes the future development of quantum nanotechnology based on attosecond physics of the subatomic level of the condensed state. There are considered the ways of realizing the main achievements of the second quantum revolution in subatomic nanotechnologies of materials, namely quantum entanglement, quantum contextuality and quantum dissipativity. The theoretical analysis of the prospects for this direction in the development of quantum subatomic nanotechnologies has been carried out within the framework of the well-known theory of thermal field dynamics of the condensed state. The analysis shows that subatomic en-tanglement of electron pairs is realized by attosecond single pulsed photons. The entangled electron pairs form the interfaces of supra-atomic capsules — quantum nanoelectromechanical systems (NEMS) of the con-densed state of the material. The Coulomb blockade of quantum NEMS interfaces is complemented by the fact that they are controlled by the infrastructure of subatomic two-electron sensors and actuators located at the interface boundaries. When the primary subatomic interfaces of NEMS function, secondary supra-atomic scale entangled pairs of electrons are generated, which dissipate the NEMS energy and form a dissipative multilevel hierarchy of condensed state interfaces at higher spatio-temporal scales of intelligent materials
{"title":"The Second Quantum Revolution: Development of Subatomic Quantum Nanotechnologies of Intelligent Materials","authors":"S. Beznosyuk","doi":"10.31489/2959-0663/3-23-5","DOIUrl":"https://doi.org/10.31489/2959-0663/3-23-5","url":null,"abstract":"The article analyzes the future development of quantum nanotechnology based on attosecond physics of the subatomic level of the condensed state. There are considered the ways of realizing the main achievements of the second quantum revolution in subatomic nanotechnologies of materials, namely quantum entanglement, quantum contextuality and quantum dissipativity. The theoretical analysis of the prospects for this direction in the development of quantum subatomic nanotechnologies has been carried out within the framework of the well-known theory of thermal field dynamics of the condensed state. The analysis shows that subatomic en-tanglement of electron pairs is realized by attosecond single pulsed photons. The entangled electron pairs form the interfaces of supra-atomic capsules — quantum nanoelectromechanical systems (NEMS) of the con-densed state of the material. The Coulomb blockade of quantum NEMS interfaces is complemented by the fact that they are controlled by the infrastructure of subatomic two-electron sensors and actuators located at the interface boundaries. When the primary subatomic interfaces of NEMS function, secondary supra-atomic scale entangled pairs of electrons are generated, which dissipate the NEMS energy and form a dissipative multilevel hierarchy of condensed state interfaces at higher spatio-temporal scales of intelligent materials","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89477696","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 : 2023-01-01DOI: 10.31489/2959-0663/3-23-13
Kamshat Sh. Makhadiyeva, L. Abulyaissova, M. S. Kasymova
Quantum chemical modeling and full geometry optimization of sisomicin and gentamicin was carried out by the correlation functional B3LYP using augmented with polarization functions for heavy atoms 6-311G(d) and Dunning’s correlation consistent cc-pVDZ basis sets. The effect of the basis set on the calculation results of molecular structure and quantum chemical descriptors of the titled compounds was studied. Special attention was paid to the intramolecular NH…N, OH…N, OH…O, NH…O hydrogen bonds in sisomicin and gentamicin. According to theoretical calculations, the distances between hydrogen and acceptor atoms are slightly larger than a typical length due to a significant deviation of the intramolecular H-bonds from a linearity. To evaluate the extent of electron density delocalization from the lone pairs of atoms into the antibonding neighboring orbitals and inside H-bonds within the systems, NBO (Natural Bond Orbital) analysis was used at two levels of theory. The most intensive interactions between electron donor and electron acceptor in the structures under consideration were determined and their delocalization energies were evaluated. Based on the obtained data, classical electrostatic nature of the weak H-bonds and conjugation effects stabilizing the molecules were suggested
{"title":"DFT-Based Study of the Intramolecular Interactions of Some Aminoglycosides","authors":"Kamshat Sh. Makhadiyeva, L. Abulyaissova, M. S. Kasymova","doi":"10.31489/2959-0663/3-23-13","DOIUrl":"https://doi.org/10.31489/2959-0663/3-23-13","url":null,"abstract":"Quantum chemical modeling and full geometry optimization of sisomicin and gentamicin was carried out by the correlation functional B3LYP using augmented with polarization functions for heavy atoms 6-311G(d) and Dunning’s correlation consistent cc-pVDZ basis sets. The effect of the basis set on the calculation results of molecular structure and quantum chemical descriptors of the titled compounds was studied. Special attention was paid to the intramolecular NH…N, OH…N, OH…O, NH…O hydrogen bonds in sisomicin and gentamicin. According to theoretical calculations, the distances between hydrogen and acceptor atoms are slightly larger than a typical length due to a significant deviation of the intramolecular H-bonds from a linearity. To evaluate the extent of electron density delocalization from the lone pairs of atoms into the antibonding neighboring orbitals and inside H-bonds within the systems, NBO (Natural Bond Orbital) analysis was used at two levels of theory. The most intensive interactions between electron donor and electron acceptor in the structures under consideration were determined and their delocalization energies were evaluated. Based on the obtained data, classical electrostatic nature of the weak H-bonds and conjugation effects stabilizing the molecules were suggested","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"10 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72595017","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 : 2023-01-01DOI: 10.31489/2959-0663/3-23-8
D. A. Sunchugashev, V. Cherepanov
In this work, the vibronic emission spectra of dithiophene (T2) and terthiophene (T3) molecules and their complexes with hydrogen sulfide and its dimmer were calculated at the TD-DFT / CAM-B3LYP / 6-31G(d) theory level. The solvent was taken into account within the PCM model. Vibronic spectra were calculated considering both the Herzberg-Teller and Duschinsky effects. Good agreement between the computed and experimental spectra was obtained. The vibration promoting modes forming vibronic progressions were found. Vibronic bands for bithiophene and terthiophene were formed by their low-frequency modes (≤370 cm–1), combinations of low-frequency modes with high-frequency modes (1497 and 1672 cm–1 for T2 and 1516 and 1573 cm–1 for T3), and with their composite high-frequency modes. The intensities of vibronic lines for the emission spectra of T2∙∙∙H2S, T3∙∙∙H2S and T2∙∙∙(H2S)2, T3∙∙∙(H2S)2 complexes were shown to de-crease 3.7, 2.6 and 5.5, 3.6 times compared to T2 and T3, respectively. The bathochromic shifts of the vibron-ic bands of dithiophene and terthiophene complexes with H2S and (H2S)2 did not exceed 130 cm–1 for all bands.
{"title":"Vibronic Emission Spectra of Dithiophene and Terthiophene and Their Complexes with H2S and (H2S)2","authors":"D. A. Sunchugashev, V. Cherepanov","doi":"10.31489/2959-0663/3-23-8","DOIUrl":"https://doi.org/10.31489/2959-0663/3-23-8","url":null,"abstract":"In this work, the vibronic emission spectra of dithiophene (T2) and terthiophene (T3) molecules and their complexes with hydrogen sulfide and its dimmer were calculated at the TD-DFT / CAM-B3LYP / 6-31G(d) theory level. The solvent was taken into account within the PCM model. Vibronic spectra were calculated considering both the Herzberg-Teller and Duschinsky effects. Good agreement between the computed and experimental spectra was obtained. The vibration promoting modes forming vibronic progressions were found. Vibronic bands for bithiophene and terthiophene were formed by their low-frequency modes (≤370 cm–1), combinations of low-frequency modes with high-frequency modes (1497 and 1672 cm–1 for T2 and 1516 and 1573 cm–1 for T3), and with their composite high-frequency modes. The intensities of vibronic lines for the emission spectra of T2∙∙∙H2S, T3∙∙∙H2S and T2∙∙∙(H2S)2, T3∙∙∙(H2S)2 complexes were shown to de-crease 3.7, 2.6 and 5.5, 3.6 times compared to T2 and T3, respectively. The bathochromic shifts of the vibron-ic bands of dithiophene and terthiophene complexes with H2S and (H2S)2 did not exceed 130 cm–1 for all bands.","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83482086","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 : 2023-01-01DOI: 10.31489/2959-0663/3-23-10
Lenara I. Valiulina, V. Cherepanov, R. Valiev
Magnetically induced ring currents, aromaticity, as well as polarizability and second hyperpolarizability of the metallocenothiaporphyrins with transition metals of group VIII (Fe, Ru) and isoelectronic cations of group IX (Со+, Rh+) and metallocene-containing annulenes ((C5H5)2М[n = 18–24] where M is Fe, Co+) have been studied computationally at Density Functional level of Theory (DFT). The calculations show that the value of average polarizability of the studied compounds depends on their character of the aromaticity. Aro-matic structures are characterized by larger polarizability than their corresponding antiaromatic congeners. The average polarizability of metallocenothiaporphyrins also depends on the magnitude of magnetically in-duced ring currents, which quantify the degree of electron delocalization. An increase in the number of -electrons in conjugation pathway plays a key role in the growth of polarizability. Aromaticity also influences on the second hyperpolarizability of metallocene-containing annulenes. In the case of compounds with the same number of conjugated electrons, the second hyperpolarizability is larger for more aromatic systems. To conclude, our results pinpoint the importance of electron delocalization on the polarizability and second hyperpolarizability of the studied metallocene-containig macrocycles
{"title":"Relationship between the Electric Polarizability and Aromaticity of Metallocene-Containing Macrocycles","authors":"Lenara I. Valiulina, V. Cherepanov, R. Valiev","doi":"10.31489/2959-0663/3-23-10","DOIUrl":"https://doi.org/10.31489/2959-0663/3-23-10","url":null,"abstract":"Magnetically induced ring currents, aromaticity, as well as polarizability and second hyperpolarizability of the metallocenothiaporphyrins with transition metals of group VIII (Fe, Ru) and isoelectronic cations of group IX (Со+, Rh+) and metallocene-containing annulenes ((C5H5)2М[n = 18–24] where M is Fe, Co+) have been studied computationally at Density Functional level of Theory (DFT). The calculations show that the value of average polarizability of the studied compounds depends on their character of the aromaticity. Aro-matic structures are characterized by larger polarizability than their corresponding antiaromatic congeners. The average polarizability of metallocenothiaporphyrins also depends on the magnitude of magnetically in-duced ring currents, which quantify the degree of electron delocalization. An increase in the number of -electrons in conjugation pathway plays a key role in the growth of polarizability. Aromaticity also influences on the second hyperpolarizability of metallocene-containing annulenes. In the case of compounds with the same number of conjugated electrons, the second hyperpolarizability is larger for more aromatic systems. To conclude, our results pinpoint the importance of electron delocalization on the polarizability and second hyperpolarizability of the studied metallocene-containig macrocycles","PeriodicalId":11690,"journal":{"name":"Eurasian Journal of Analytical Chemistry","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76936472","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 : 2023-01-01DOI: 10.31489/2959-0663/1-23-4
D. S. Saiko, Sergey A. Titov, I. Saranov, Danila G. Andreev, Natalja N. Lobacheva
In this work, studies were carried out on the water evaporation from concentrated solutions of such sugars as sucrose, fructose, glucose, galactose, to determine the evaporation mechanisms. Differential scanning calo-rimetry (DSC) method in the temperature range from –70 °C to +200 °C, as well as the combined thermo-gravimetric analysis with differential scanning calorimetry under isothermal conditions at temperatures of 30, 45, 60 °C were used. The analysis of the DSC curves of sucrose solutions at low temperatures shows that in sugar solutions with a concentration of 65 %, water does not produce melting peaks. Therefore, it can be con-sidered bound in the first hydration shells of sucrose. Isothermal thermogravimetric measurements give close to linear dependences of mass loss on time, and their slope being determined by temperature. At higher con-centrations of sucrose solutions DSC curves for disaccharides are shifted relative to the curves for monosac-charides. This may be due to the lower permeability of the film surface for water. The evaporation model based on the vacancy mechanism of water molecules movement in concentrated sugar solutions was pro-posed. According to this model, the region enriched with vacancies of water molecules gradually penetrates deep into the sample. In this case, the number of water molecules in each layer of the region sets at a certain level. The given model constructions are applicable to the initial stages of water evaporation from concentrat-ed sugar solutions.
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