Lyudmila Parfenova - Academia.edu (original) (raw)
Papers by Lyudmila Parfenova
Journal of Natural Products
Materials
The problem of the optimization of properties for biocompatible coatings as functional materials ... more The problem of the optimization of properties for biocompatible coatings as functional materials requires in-depth understanding of the coating formation processes; this allows for precise manufacturing of new generation implantable devices. Plasma electrolytic oxidation (PEO) opens the possibility for the design of biomimetic surfaces for better biocompatibility of titanium materials. The pulsed bipolar PEO process of cp-Ti under voltage control was investigated using joint analysis of the surface characterization and by in situ methods of impedance spectroscopy and optical emission spectroscopy. Scanning electron microscopy, X-ray diffractometry, coating thickness, and roughness measurements were used to characterize the surface morphology evolution during the treatment for 5 min. In situ impedance spectroscopy facilitated the evaluation of the PEO process frequency response and proposed the underlying equivalent circuit where parameters were correlated with the coating layer prop...
Phytochemistry Reviews
Ecdysteroids are polyhydroxylated sterols, and are widespread in the plant and animal world. To d... more Ecdysteroids are polyhydroxylated sterols, and are widespread in the plant and animal world. To date, over 520 ecdysteroids have been isolated from natural sources. The most accessible and studied representative of this class of compounds is 20-hydroxyecdysone (20E)—a universal hormone for the development and vital activity of insects and crustaceans. Moreover, ecdysteroids exhibit a wide spectrum of pharmacological activity for humans, without exerting toxic, androgenic, or estrogenic effects. In this regard, the search for new structures of ecdysteroids and their semi-synthetic analogs obtained as a result of various chemical transformations is in high demand. The review summarizes data for the period 2011–2021 regarding recent advances in the isolation of novel natural ecdysteroids, the chemical modifications, biological activity of semi-synthetic analogs and their prospects for practice.
Molecules, 2021
1-Hexene transformations in the catalytic systems L2MCl2–XAlBui2 (L = Cp, M = Ti, Zr, Hf; L = Ind... more 1-Hexene transformations in the catalytic systems L2MCl2–XAlBui2 (L = Cp, M = Ti, Zr, Hf; L = Ind, rac-H4C2[THInd]2, M = Zr; X = H, Bu i) and [Cp2ZrH2]2-ClAlR2 activated by MMAO-12, B(C6F5)3, or (Ph3C)[B(C6F5)4] in chlorinated solvents (CH2Cl2, CHCl3, o-Cl2C6H4, ClCH2CH2Cl) were studied. The systems [Cp2ZrH2]2-MMAO-12, [Cp2ZrH2]2-ClAlBui2-MMAO-12, or Cp2ZrCl2-HAlBui2-MMAO-12 (B(C6F5)3) in CH2Cl2 showed the highest activity and selectivity towards the formation of vinylidene head-to-tail alkene dimers. The use of chloroform as a solvent provides further in situ dimer dimerization to give a tetramer yield of up to 89%. A study of the reaction of [Cp2ZrH2]2 or Cp2ZrCl2 with organoaluminum compounds and MMAO-12 by NMR spectroscopy confirmed the formation of Zr,Zr-hydride clusters as key intermediates of the alkene dimerization. The probable structure of the Zr,Zr-hydride clusters and ways of their generation in the catalytic systems were analyzed using a quantum chemical approach (DFT).
The reaction between zirconocene dichloride and excess diethylzinc in d-6-benzene solution was st... more The reaction between zirconocene dichloride and excess diethylzinc in d-6-benzene solution was studied. It was found that the exchange reaction between Cp2ZrCl2 and Et2Zn is accompanied by the formation of such complexes as bis-(cyclopentadienyl)ethylzirconium chloride (EtZrCp2Cl), a zirconium-organozinc complex, and bis-(cyclopentadienyl)diethylzirconium (Et2ZrCp2). It was also found that as a result of ligand exchange in zirconocene dichloride–diethylzinc bimetallic systems, the zirconium-organozinc complex is formed in minor amounts. An assessment of the thermodynamic stability of the obtained products is given based on the results of DFT analysis. The description of the NMR spectral data of the obtained organozirconium complexes is carried out.
Molecular Catalysis, 2021
Abstract The reactions of zirconocene hydride, alkyl, and metallacyclopropane intermediates with ... more Abstract The reactions of zirconocene hydride, alkyl, and metallacyclopropane intermediates with chain and cluster models of methylaluminoxane (MAO) have been studied using a quantum chemical approach (DFT). These reactions are considered as possible activation steps of the key intermediates in various olefin transformations. Complexes with MAO differing in the structure and stability were tested for the propene insertion stage for which thermodynamic and activation parameters were determined. Comparative analysis of the results demonstrated a significant role of chain and cage MAO structures in the formation of the sites most active toward the alkene.
AIP Conference Proceedings, 2022
Synthesis of methyl 7-formylabieta-7,13-dien-18-oate was achieved by formylation of the abietic a... more Synthesis of methyl 7-formylabieta-7,13-dien-18-oate was achieved by formylation of the abietic acid methyl ester under Vilsmeier-Haack conditions. The in vitro cytotoxicity of the abietic and dehydroabietic acid derivatives against the NCI-60 cancer cell line panel was also studied. The dehydroabietic acid aminopropargyles showed promising antitumor activity against leukemia CCRF-CEM and RPMI-8226 cancer cell lines. RESULTS AND DISCUSSION Vilsmeier-Haack reaction of methyl abietate 1 has been carried out with various chlorinating agents such as POCl 3 , SOCl 2 and (COCl) 2 in the presence of DMF (Scheme 1). The dependence of yield of the formylated product on the reaction conditions is shown in Table 1. Among the tested Vilsmeier-Haack reagents, (COCl) 2 and DMF provided the 7-formyl derivative 2 in good yield (Table 1).
AIP Conference Proceedings, 2022
The effective one-pot method for the synthesis of new quaternized pyridine substituted analogs of... more The effective one-pot method for the synthesis of new quaternized pyridine substituted analogs of betulin has been developed. The method is based on the reaction of the initial triterpene with organic tribromides in pyridines. The effect of various organic tribromides (Tempo + Br3-, TBA + Br3-, Py•HBr•Br2) and pyridines (pyridine, 3,5-lutidine, 2,6lutidine, 4-picoline, and 2,4,6-collidine) in the yield of the desired products have also been investigated.
Alkenes, 2018
Alkene and olefin functionalization via addition of electro-or nucleophilic reagents is one of th... more Alkene and olefin functionalization via addition of electro-or nucleophilic reagents is one of the convenient synthetic methods for the insertion of heteroatoms into organic molecules. The use of organometallic reagents in these reactions in combination with the specific catalysts provides high substrate conversion and process selectivity. The introduction of this approach into the chemistry of organoaluminum compounds leads to the development of chemo-, regio-and stereoselective catalytic methods of alkene and olefin functionalization. The chapter focuses on the modern concepts of the alkene hydro-, carbo-and cycloalumination mechanisms, that is, the experimental and theoretical data on the intermediate structures involved in the product formation, the effects of the catalyst and organoaluminum compound structure, reaction conditions on the activity and selectivity of the bimetallic systems. The prospects of the development of enantioselective methods using these catalytic systems for the alkene and olefin transformations are considered.
Luminescence, 2021
The spectral-luminescent properties of 23 samples of zirconium complexes were studied. Mechanolum... more The spectral-luminescent properties of 23 samples of zirconium complexes were studied. Mechanoluminescence spectra of 10 complexes were obtained. The solid-state component of the mechanoluminescence spectrum, that is, the luminescence of the crystal itself, coincides with the photoluminescence spectra of these complexes, which attests to identical emission from the same excited states in the mechano- and photoluminescence, despite the different ways of excitation. The luminescence maximum is red-shifted as substituents appear in the ligand, in particular in the presence of a bridging group connecting π-ligands (ansa-complexes) and also on going to a substituted bis-indenyl complex rac- Me2 Si(2-Me-4-Ph-5-OMe-6-But -Ind)2 ZrCl2 ). It was found that mechanical destruction of rac-isomer of complex Mе2 С(2-Me-4-But -C5 H2 )2 ZrCl2 , unlike that of meso- isomer, is accompanied by a more than tenfold increase in the intensity and by a shift of the mechanoluminescence spectrum to longer wavelengths.
Chemistry of Heterocyclic Compounds, 2020
Chemico-Biological Interactions, 2021
The present study describes the synthesis of pyridinium derivatives of betulin, including new 4-m... more The present study describes the synthesis of pyridinium derivatives of betulin, including new 4-methyl- and 3,5-methyl-pyridinium analogs, their effect on artificial membrane systems (liposomes), cytotoxicity in models of prokaryotic (E. coli K-12 MG1655) and eukaryotic cells (rat thymocytes), as well as their effect on the functioning of membrane systems of rat liver mitochondria. We have shown that the presence of methyl groups in the pyridine ring of compounds determines the ability of the derivatives to effectively permeabilize the artificial membrane of lecithin liposomes for the fluorescent probe sulforhodamine B. The 4-methyl- and 3,5-methyl-pyridinium analogs inhibit the growth of E. coli K-12 MG1655 and, at the same time, did not have a cytotoxic effect on rat thymocytes. However, in the latter case, we noted a decrease in the mitochondrial potential of cells. The studied compounds reduced the functional activity of mitochondria, suppressing the activity of complexes of the respiratory chain and reducing the membrane potential. In addition, compounds containing methyl groups in the p- and m-positions of the pyridine ring were also able to permeabilize the inner membrane of mitochondria, causing them to swell. In this case, the most lipophilic compound containing two methyl substituents at the m-position of the pyridine fragment was most effective and had a protonophore effect on mitochondria. The paper discusses the dependence of the membranotropic and biological actions of the quaternized pyridine derivatives of betulin on their structure and lipophilicity.
Molecules, 2020
Currently, significant attention is attracted to the problem of the development of the specific a... more Currently, significant attention is attracted to the problem of the development of the specific architecture and composition of the surface layer in order to control the biocompatibility of implants made of titanium and its alloys. The titanium surface properties can be tuned both by creating an inorganic sublayer with the desired morphology and by organic top coating contributing to bioactivity. In this work, we developed a composite biologically active coatings based on hybrid molecules obtained by chemical cross-linking of amino acid bisphosphonates with a linear tripeptide RGD, in combination with inorganic porous sublayer created on titanium by plasma electrolytic oxidation (PEO). After the addition of organic molecules, the PEO coated surface gets nobler, but corrosion currents increase. In vitro studies on proliferation and viability of fibroblasts, mesenchymal stem cells and osteoblast-like cells showed the significant dependence of the molecule bioactivity on the structure ...
Surface and Coatings Technology, 2020
The paper concerns a choice in the biofunctionalization of the coatings produced by plasma electr... more The paper concerns a choice in the biofunctionalization of the coatings produced by plasma electrolytic oxidation: either with inorganic components by introducing CaP P-containing compounds into the coating (primarily hydroxyapatite), or with integrin-active organic components (primarily RGD peptides). The following coatings were analyzed: E1-titania PEO coating, E2-titania and CaP P containing PEO coating, E1 + RGDtitania PEO coating modified with integrin-active RGD (arginine-glycine-aspartic acid) tripeptide sequence anchored to the surface with a bisphosphonate linker. In terms of wear resistance, electrochemical corrosion behavior, and interaction with osteoblast-like cells, coating E1 + RGD seems to be the most promising for the titanium implants.
Catalysts, 2020
The activity and chemoselectivity of the Cp2ZrCl2-XAlBui2 (X = H, Bui) and [Cp2ZrH2]2-ClAlEt2 cat... more The activity and chemoselectivity of the Cp2ZrCl2-XAlBui2 (X = H, Bui) and [Cp2ZrH2]2-ClAlEt2 catalytic systems activated by (Ph3C)[B(C6F5)4] or B(C6F5)3 were studied in reactions with 1-hexene. The activation of the systems by B(C6F5)3 resulted in the selective formation of head-to-tail alkene dimers in up to 93% yields. NMR studies of the reactions of Zr complexes with organoaluminum compounds (OACs) and boron activators showed the formation of Zr,Zr- and Zr,Al-hydride intermediates, for which diffusion coefficients, hydrodynamic radii, and volumes were estimated using the diffusion ordered spectroscopy DOSY. Bis-zirconium hydride clusters of type x[Cp2ZrH2∙Cp2ZrHCl∙ClAlR2]∙yRnAl(C6F5)3−n were found to be the key intermediates of alkene dimerization, whereas cationic Zr,Al-hydrides led to the formation of oligomers.
Journal of Molecular Structure, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Natural Product Research, 2020
The introduction of the alkynyl moiety to the abietane diterpenic core by the modification of the... more The introduction of the alkynyl moiety to the abietane diterpenic core by the modification of the cycle E of dihydroquinopimaric acid methyl ester is described. The arylpropargyl, aminopropargyl, and 1,2,3-triazole derivatives are synthesized via Sonogashira reaction, Mannich reaction and click-chemistry, correspondingly. The antitumor effect towards the NCI-60 cancer cell line panel and antimicrobial activity against key ESKAPE pathogens of the synthesized compounds were studied in vitro. The cytotoxicity and hemolytic activity of the abietane derivatives was tested using HEK293 human embryonic kidney cell line and the human red blood cells, correspondingly. The methyl dihydroquinopimarate propargyl analogs showed high antitumor activity against leukemia (CCRF-CEM; SR), non-small cell lung cancer (NCI-H522), melanoma (LOX IMVI; MALME-3M), ovarian cancer (IGROV1), and renal cancer (786-0; UO-31) cell lines. The Mannich's diterpene bases with pyrrolidine and diethylamine fragments exhibited fungicidal activity towards Cr. neoformans (MIC= 16 μg/ml), while possessing low toxicity. The described modifications of the abietane diterpenoids have great potential for further development of new cytotoxic and fungicidal compounds.
Molecules, 2020
Being valuable precursors in the production of adhesives, lubricants, and other high-performance ... more Being valuable precursors in the production of adhesives, lubricants, and other high-performance synthetic compounds, alkene dimers and oligomers can be obtained using homogeneous zirconocene catalytic systems. Further advances in such systems require precise control of their activity and chemoselectivity, increasing both the purity and yield of the products. This relies on the process mechanism usually built around the consideration of the hydride complexes as active intermediates in the alkene di- and oligomerization; however, the majority of studies lack the direct evidence of their involvement. Parallel studies on a well-known Cp2ZrCl2-AlR3 or HAlBui2 and a novel [Cp2ZrH2]2-ClAlR2 (R = Me, Et, Bui) systems activated by methylaluminoxane (MMAO-12) have shown a deep similarity both in the catalytic performance and intermediate composition. As a result of the NMR studies, among all the intermediates considered, we proved that new Zr,Zr- hydride complexes having the type x[Cp2ZrH2∙C...
Journal of Natural Products
Materials
The problem of the optimization of properties for biocompatible coatings as functional materials ... more The problem of the optimization of properties for biocompatible coatings as functional materials requires in-depth understanding of the coating formation processes; this allows for precise manufacturing of new generation implantable devices. Plasma electrolytic oxidation (PEO) opens the possibility for the design of biomimetic surfaces for better biocompatibility of titanium materials. The pulsed bipolar PEO process of cp-Ti under voltage control was investigated using joint analysis of the surface characterization and by in situ methods of impedance spectroscopy and optical emission spectroscopy. Scanning electron microscopy, X-ray diffractometry, coating thickness, and roughness measurements were used to characterize the surface morphology evolution during the treatment for 5 min. In situ impedance spectroscopy facilitated the evaluation of the PEO process frequency response and proposed the underlying equivalent circuit where parameters were correlated with the coating layer prop...
Phytochemistry Reviews
Ecdysteroids are polyhydroxylated sterols, and are widespread in the plant and animal world. To d... more Ecdysteroids are polyhydroxylated sterols, and are widespread in the plant and animal world. To date, over 520 ecdysteroids have been isolated from natural sources. The most accessible and studied representative of this class of compounds is 20-hydroxyecdysone (20E)—a universal hormone for the development and vital activity of insects and crustaceans. Moreover, ecdysteroids exhibit a wide spectrum of pharmacological activity for humans, without exerting toxic, androgenic, or estrogenic effects. In this regard, the search for new structures of ecdysteroids and their semi-synthetic analogs obtained as a result of various chemical transformations is in high demand. The review summarizes data for the period 2011–2021 regarding recent advances in the isolation of novel natural ecdysteroids, the chemical modifications, biological activity of semi-synthetic analogs and their prospects for practice.
Molecules, 2021
1-Hexene transformations in the catalytic systems L2MCl2–XAlBui2 (L = Cp, M = Ti, Zr, Hf; L = Ind... more 1-Hexene transformations in the catalytic systems L2MCl2–XAlBui2 (L = Cp, M = Ti, Zr, Hf; L = Ind, rac-H4C2[THInd]2, M = Zr; X = H, Bu i) and [Cp2ZrH2]2-ClAlR2 activated by MMAO-12, B(C6F5)3, or (Ph3C)[B(C6F5)4] in chlorinated solvents (CH2Cl2, CHCl3, o-Cl2C6H4, ClCH2CH2Cl) were studied. The systems [Cp2ZrH2]2-MMAO-12, [Cp2ZrH2]2-ClAlBui2-MMAO-12, or Cp2ZrCl2-HAlBui2-MMAO-12 (B(C6F5)3) in CH2Cl2 showed the highest activity and selectivity towards the formation of vinylidene head-to-tail alkene dimers. The use of chloroform as a solvent provides further in situ dimer dimerization to give a tetramer yield of up to 89%. A study of the reaction of [Cp2ZrH2]2 or Cp2ZrCl2 with organoaluminum compounds and MMAO-12 by NMR spectroscopy confirmed the formation of Zr,Zr-hydride clusters as key intermediates of the alkene dimerization. The probable structure of the Zr,Zr-hydride clusters and ways of their generation in the catalytic systems were analyzed using a quantum chemical approach (DFT).
The reaction between zirconocene dichloride and excess diethylzinc in d-6-benzene solution was st... more The reaction between zirconocene dichloride and excess diethylzinc in d-6-benzene solution was studied. It was found that the exchange reaction between Cp2ZrCl2 and Et2Zn is accompanied by the formation of such complexes as bis-(cyclopentadienyl)ethylzirconium chloride (EtZrCp2Cl), a zirconium-organozinc complex, and bis-(cyclopentadienyl)diethylzirconium (Et2ZrCp2). It was also found that as a result of ligand exchange in zirconocene dichloride–diethylzinc bimetallic systems, the zirconium-organozinc complex is formed in minor amounts. An assessment of the thermodynamic stability of the obtained products is given based on the results of DFT analysis. The description of the NMR spectral data of the obtained organozirconium complexes is carried out.
Molecular Catalysis, 2021
Abstract The reactions of zirconocene hydride, alkyl, and metallacyclopropane intermediates with ... more Abstract The reactions of zirconocene hydride, alkyl, and metallacyclopropane intermediates with chain and cluster models of methylaluminoxane (MAO) have been studied using a quantum chemical approach (DFT). These reactions are considered as possible activation steps of the key intermediates in various olefin transformations. Complexes with MAO differing in the structure and stability were tested for the propene insertion stage for which thermodynamic and activation parameters were determined. Comparative analysis of the results demonstrated a significant role of chain and cage MAO structures in the formation of the sites most active toward the alkene.
AIP Conference Proceedings, 2022
Synthesis of methyl 7-formylabieta-7,13-dien-18-oate was achieved by formylation of the abietic a... more Synthesis of methyl 7-formylabieta-7,13-dien-18-oate was achieved by formylation of the abietic acid methyl ester under Vilsmeier-Haack conditions. The in vitro cytotoxicity of the abietic and dehydroabietic acid derivatives against the NCI-60 cancer cell line panel was also studied. The dehydroabietic acid aminopropargyles showed promising antitumor activity against leukemia CCRF-CEM and RPMI-8226 cancer cell lines. RESULTS AND DISCUSSION Vilsmeier-Haack reaction of methyl abietate 1 has been carried out with various chlorinating agents such as POCl 3 , SOCl 2 and (COCl) 2 in the presence of DMF (Scheme 1). The dependence of yield of the formylated product on the reaction conditions is shown in Table 1. Among the tested Vilsmeier-Haack reagents, (COCl) 2 and DMF provided the 7-formyl derivative 2 in good yield (Table 1).
AIP Conference Proceedings, 2022
The effective one-pot method for the synthesis of new quaternized pyridine substituted analogs of... more The effective one-pot method for the synthesis of new quaternized pyridine substituted analogs of betulin has been developed. The method is based on the reaction of the initial triterpene with organic tribromides in pyridines. The effect of various organic tribromides (Tempo + Br3-, TBA + Br3-, Py•HBr•Br2) and pyridines (pyridine, 3,5-lutidine, 2,6lutidine, 4-picoline, and 2,4,6-collidine) in the yield of the desired products have also been investigated.
Alkenes, 2018
Alkene and olefin functionalization via addition of electro-or nucleophilic reagents is one of th... more Alkene and olefin functionalization via addition of electro-or nucleophilic reagents is one of the convenient synthetic methods for the insertion of heteroatoms into organic molecules. The use of organometallic reagents in these reactions in combination with the specific catalysts provides high substrate conversion and process selectivity. The introduction of this approach into the chemistry of organoaluminum compounds leads to the development of chemo-, regio-and stereoselective catalytic methods of alkene and olefin functionalization. The chapter focuses on the modern concepts of the alkene hydro-, carbo-and cycloalumination mechanisms, that is, the experimental and theoretical data on the intermediate structures involved in the product formation, the effects of the catalyst and organoaluminum compound structure, reaction conditions on the activity and selectivity of the bimetallic systems. The prospects of the development of enantioselective methods using these catalytic systems for the alkene and olefin transformations are considered.
Luminescence, 2021
The spectral-luminescent properties of 23 samples of zirconium complexes were studied. Mechanolum... more The spectral-luminescent properties of 23 samples of zirconium complexes were studied. Mechanoluminescence spectra of 10 complexes were obtained. The solid-state component of the mechanoluminescence spectrum, that is, the luminescence of the crystal itself, coincides with the photoluminescence spectra of these complexes, which attests to identical emission from the same excited states in the mechano- and photoluminescence, despite the different ways of excitation. The luminescence maximum is red-shifted as substituents appear in the ligand, in particular in the presence of a bridging group connecting π-ligands (ansa-complexes) and also on going to a substituted bis-indenyl complex rac- Me2 Si(2-Me-4-Ph-5-OMe-6-But -Ind)2 ZrCl2 ). It was found that mechanical destruction of rac-isomer of complex Mе2 С(2-Me-4-But -C5 H2 )2 ZrCl2 , unlike that of meso- isomer, is accompanied by a more than tenfold increase in the intensity and by a shift of the mechanoluminescence spectrum to longer wavelengths.
Chemistry of Heterocyclic Compounds, 2020
Chemico-Biological Interactions, 2021
The present study describes the synthesis of pyridinium derivatives of betulin, including new 4-m... more The present study describes the synthesis of pyridinium derivatives of betulin, including new 4-methyl- and 3,5-methyl-pyridinium analogs, their effect on artificial membrane systems (liposomes), cytotoxicity in models of prokaryotic (E. coli K-12 MG1655) and eukaryotic cells (rat thymocytes), as well as their effect on the functioning of membrane systems of rat liver mitochondria. We have shown that the presence of methyl groups in the pyridine ring of compounds determines the ability of the derivatives to effectively permeabilize the artificial membrane of lecithin liposomes for the fluorescent probe sulforhodamine B. The 4-methyl- and 3,5-methyl-pyridinium analogs inhibit the growth of E. coli K-12 MG1655 and, at the same time, did not have a cytotoxic effect on rat thymocytes. However, in the latter case, we noted a decrease in the mitochondrial potential of cells. The studied compounds reduced the functional activity of mitochondria, suppressing the activity of complexes of the respiratory chain and reducing the membrane potential. In addition, compounds containing methyl groups in the p- and m-positions of the pyridine ring were also able to permeabilize the inner membrane of mitochondria, causing them to swell. In this case, the most lipophilic compound containing two methyl substituents at the m-position of the pyridine fragment was most effective and had a protonophore effect on mitochondria. The paper discusses the dependence of the membranotropic and biological actions of the quaternized pyridine derivatives of betulin on their structure and lipophilicity.
Molecules, 2020
Currently, significant attention is attracted to the problem of the development of the specific a... more Currently, significant attention is attracted to the problem of the development of the specific architecture and composition of the surface layer in order to control the biocompatibility of implants made of titanium and its alloys. The titanium surface properties can be tuned both by creating an inorganic sublayer with the desired morphology and by organic top coating contributing to bioactivity. In this work, we developed a composite biologically active coatings based on hybrid molecules obtained by chemical cross-linking of amino acid bisphosphonates with a linear tripeptide RGD, in combination with inorganic porous sublayer created on titanium by plasma electrolytic oxidation (PEO). After the addition of organic molecules, the PEO coated surface gets nobler, but corrosion currents increase. In vitro studies on proliferation and viability of fibroblasts, mesenchymal stem cells and osteoblast-like cells showed the significant dependence of the molecule bioactivity on the structure ...
Surface and Coatings Technology, 2020
The paper concerns a choice in the biofunctionalization of the coatings produced by plasma electr... more The paper concerns a choice in the biofunctionalization of the coatings produced by plasma electrolytic oxidation: either with inorganic components by introducing CaP P-containing compounds into the coating (primarily hydroxyapatite), or with integrin-active organic components (primarily RGD peptides). The following coatings were analyzed: E1-titania PEO coating, E2-titania and CaP P containing PEO coating, E1 + RGDtitania PEO coating modified with integrin-active RGD (arginine-glycine-aspartic acid) tripeptide sequence anchored to the surface with a bisphosphonate linker. In terms of wear resistance, electrochemical corrosion behavior, and interaction with osteoblast-like cells, coating E1 + RGD seems to be the most promising for the titanium implants.
Catalysts, 2020
The activity and chemoselectivity of the Cp2ZrCl2-XAlBui2 (X = H, Bui) and [Cp2ZrH2]2-ClAlEt2 cat... more The activity and chemoselectivity of the Cp2ZrCl2-XAlBui2 (X = H, Bui) and [Cp2ZrH2]2-ClAlEt2 catalytic systems activated by (Ph3C)[B(C6F5)4] or B(C6F5)3 were studied in reactions with 1-hexene. The activation of the systems by B(C6F5)3 resulted in the selective formation of head-to-tail alkene dimers in up to 93% yields. NMR studies of the reactions of Zr complexes with organoaluminum compounds (OACs) and boron activators showed the formation of Zr,Zr- and Zr,Al-hydride intermediates, for which diffusion coefficients, hydrodynamic radii, and volumes were estimated using the diffusion ordered spectroscopy DOSY. Bis-zirconium hydride clusters of type x[Cp2ZrH2∙Cp2ZrHCl∙ClAlR2]∙yRnAl(C6F5)3−n were found to be the key intermediates of alkene dimerization, whereas cationic Zr,Al-hydrides led to the formation of oligomers.
Journal of Molecular Structure, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Natural Product Research, 2020
The introduction of the alkynyl moiety to the abietane diterpenic core by the modification of the... more The introduction of the alkynyl moiety to the abietane diterpenic core by the modification of the cycle E of dihydroquinopimaric acid methyl ester is described. The arylpropargyl, aminopropargyl, and 1,2,3-triazole derivatives are synthesized via Sonogashira reaction, Mannich reaction and click-chemistry, correspondingly. The antitumor effect towards the NCI-60 cancer cell line panel and antimicrobial activity against key ESKAPE pathogens of the synthesized compounds were studied in vitro. The cytotoxicity and hemolytic activity of the abietane derivatives was tested using HEK293 human embryonic kidney cell line and the human red blood cells, correspondingly. The methyl dihydroquinopimarate propargyl analogs showed high antitumor activity against leukemia (CCRF-CEM; SR), non-small cell lung cancer (NCI-H522), melanoma (LOX IMVI; MALME-3M), ovarian cancer (IGROV1), and renal cancer (786-0; UO-31) cell lines. The Mannich's diterpene bases with pyrrolidine and diethylamine fragments exhibited fungicidal activity towards Cr. neoformans (MIC= 16 μg/ml), while possessing low toxicity. The described modifications of the abietane diterpenoids have great potential for further development of new cytotoxic and fungicidal compounds.
Molecules, 2020
Being valuable precursors in the production of adhesives, lubricants, and other high-performance ... more Being valuable precursors in the production of adhesives, lubricants, and other high-performance synthetic compounds, alkene dimers and oligomers can be obtained using homogeneous zirconocene catalytic systems. Further advances in such systems require precise control of their activity and chemoselectivity, increasing both the purity and yield of the products. This relies on the process mechanism usually built around the consideration of the hydride complexes as active intermediates in the alkene di- and oligomerization; however, the majority of studies lack the direct evidence of their involvement. Parallel studies on a well-known Cp2ZrCl2-AlR3 or HAlBui2 and a novel [Cp2ZrH2]2-ClAlR2 (R = Me, Et, Bui) systems activated by methylaluminoxane (MMAO-12) have shown a deep similarity both in the catalytic performance and intermediate composition. As a result of the NMR studies, among all the intermediates considered, we proved that new Zr,Zr- hydride complexes having the type x[Cp2ZrH2∙C...