Yevgen Karpichev | Tallinn University of Technology (original) (raw)
Papers by Yevgen Karpichev
![Research paper thumbnail of Crystal Structure and Magnetic Properties of Peacock–Weakley Type Polyoxometalates Na9[Ln(W5O18)2] (Ln = Tm, Yb): Rare Example of Tm(III) SMM](https://attachments.academia-assets.com/106563831/thumbnails/1.jpg)
](Magnetochemistry, Oct 21, 2020
We report Peacock-Weakley complexes, Na 9 [Ln(W 5 O 18) 2 ]•35H 2 O, formed with Tm(III), 1, and ... more We report Peacock-Weakley complexes, Na 9 [Ln(W 5 O 18) 2 ]•35H 2 O, formed with Tm(III), 1, and Yb(III), 2. Their syntheses, physico-chemical characterizations, crystal structures, and magnetic properties are described. Ab initio calculations are also reported. These polyoxometalate (POM) complexes were obtained using original synthetic conditions where acidification was performed with a stoichiometric amount of nitric acid to an acidity of Z = ν(H +)/ν(WO 4 2-) = 8/10 = 0.80. Both the Tm(III) and Yb(III) derivatives were found to exhibit field-induced slow relaxation of their magnetization likely controlled by Raman and Orbach relaxation processes. 1 is a rare example of a Tm(III)-based single-molecule magnet (SMM) and is a consequence of the oblate tetragonal anti-prismatic symmetry of the coordination sphere.
Molecules
Novel composite self-disinfecting films of polylactic acid (PLA) filled with nanosized particles ... more Novel composite self-disinfecting films of polylactic acid (PLA) filled with nanosized particles of double sodium–copper(II) paratungstate B Na2Cu3(CuOH)2[W12O40(OH)2]·32H2O (POM) were developed. The solvent casting (POM/PLA film) and solvent-free melt extrusion methods (Extr. POM/PLA film) were applied for film preparation. The copper (II) ion release to water from both types of the films after 10 days at different temperatures demonstrated that the PLA matrix acts as a diffusion barrier, and the resulting concentration of released copper in water at room temperature remained low, at 0.79% for POM/PLA film and 0.51% for Extr. POM/PLA film. The POM-containing films reveals a significant inhibitory effect against E. coli ATCC 25922 in the agar diffusion test. The numbers of CFUs in washes of the films after incubation for 24 h were found to be 3.6 log CFU mL–1 (POM/PLA film) and 4.1 log CFU mL–1 (Extr. POM/PLA film). The films combine the antibacterial properties of POM and a bio-bas...
Russian Journal of Organic Chemistry, 2012
Processes of cleavage of 4-nitrophenyl esters of diethylphosphoric, diethylphosphonic, and 4-tolu... more Processes of cleavage of 4-nitrophenyl esters of diethylphosphoric, diethylphosphonic, and 4-toluenesulfonic acids were investigated occurring in micelles of surfactants containing supernucleophilic oximate fragment and on their analogs not forming micelles in water. At transferring the reaction from water into the micelles of functional surfactants the reaction accelerates 10 2-10 3 times. This acceleration is caused by the concentration of the substrate, for the nucleophilicity of the oximate fragment changes insignifi cantly. The reactivity of the functional surfactants is described by the Brønsted dependence with a break, its character is analogous to the dependence of the oximes non-forming micelles.
Bioresource Technology, 2020
Lignocellulosic biomass is the most plentiful renewable biomolecule and an alternative bioresourc... more Lignocellulosic biomass is the most plentiful renewable biomolecule and an alternative bioresource for the production of biofuels and biochemicals in biorefineries. But biomass recalcitrance is a bottleneck in their usage, thus necessitating their pretreatment for hydrolysis. Most pretreatment technologies, result in toxic by-products or have lower yield. Ionic liquids (ILs) have successfully advanced as 'greener and recyclable' alternatives to volatile organic solvents for lignocellulosic biomass dissolution. This review covers recent developments made in usage of IL-based techniques with focus on biomass breakdown mechanism, process parameter design, impact of cation and anion groups, and the advantageous impact of ILs on the subsequent processing of the fractionated biomass. Progress and barriers for large-scale commercial usage of ILs in emerging biorefineries were critically evaluated using the principles of economies of scale and green chemistry in an environmentally sustainable way.
A series of L-phenylalanine ionic liquids (ILs), L-tyrosine ILs, tertiary amino analogues and pro... more A series of L-phenylalanine ionic liquids (ILs), L-tyrosine ILs, tertiary amino analogues and proposed transformation products (PTPs) have been synthesised. Antimicrobial toxicity data, as part of the green chemistry metrics evaluation and to supplement preliminary biodegradation studies, was determined for ILs, tertiary amino analogues and PTPs. Good to very good overall yields (76 to 87%) for the synthesis of 6 ILs from L-phenylalanine were achieved. A C2-symmetric IL was prepared from TMS-imidazole in a one-pot two-step method in excellent yield (91%). Synthesis of the L-tyrosine IL derivatives utilised a simple protection group strategy by using an extra equivalent of the bromoacetyl bromide reagent. Improvements in the synthesis of the α-bromoamide alkylating reagent from L-phenylalanine were achieved, directed by green chemistry metric analysis. A solvent switch from dichloromethane to THF is described, however the yield was 15% lower. Antimicrobial activity testing of L-phenylalanine ILs, L-tyrosine ILs, tertiary amino analogues and PTPs, against 8 bacteria and 12 fungi strains, showed that no compound had a high antimicrobial activity, apart from an L-proline analogue. In this exceptional case, the highest toxicity (IC95 = 125 and 250 μM) was observed towards the two Gram positive strains Staphylococcus aureus and Staphylococcus epidermidis respectively. High antimicrobial activity was not found for the other bacteria or fungi strains screened. The limitations of the antimicrobial activity study is discussed in relation to SAR studies. Preliminary analysis of biodegradation data (Closed Bottle Test, OECD 301D) is presented. The pyridinium IL derivative is the preferred green IL of the series based on synthesis, toxicity and biodegradation considerations. This work is a joint study with Kümmerer and co-workers and the PTPs were selected as target compounds based on concurrent biodegradation studies by the Kümmerer group. For the comprehensive biodegradation and transformation product analysis see the accompanying paper.
We report on a new approach for creating water-soluble functionalized vesicles employing N-alkyl-... more We report on a new approach for creating water-soluble functionalized vesicles employing N-alkyl-3-boronopyridinium triflates (alkyl = Me, C 12 H 25 , C 16 H 33) as sensors for monosaccharides. The nanoaggregate properties were studied by means of DLS, TEM, high-resolution 1 H NMR, and the solvatochromic dyes Reichardt's betaine and Methyl Orange. The vesicles were shown to have 30−200 nm diameters depending on the amphiphile chain length. Diol binding to the vesicles was studied by steady-state fluorescence and UV−vis using Alizarin Red S as a probe in the solution at pH 7.4 in the presence and in the absence of D-glucose and D-fructose. Strong sensing ability of boronic acid functional moieties in the order D-fructose > D-glucose was demonstrated, and apparent binding constants were estimated.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2016
ACS Sustainable Chemistry & Engineering, 2016
Journal of Surfactants and Detergents, 2016
Russian Journal of Physical Chemistry B
Russian Journal of Organic Chemistry
Russian Chemical Bulletin
Effect of the spacer structure (linear, cyclic, bicyclic) and the presence of dissymmetry of alky... more Effect of the spacer structure (linear, cyclic, bicyclic) and the presence of dissymmetry of alkyl fragments in the series of dicationic dimeric (gemini) surfactants on the ability to form thermotropic liquid crystals and micellar properties was investigated. The transitions crystals – thermotropic LC – isotropic solution were studied using methods of differential scanning calorimetry and polarized optical microscopy. Self-diffusion coefficients of the micelles and monomers of dicationic dialkyl derivatives of 1,4-diazabicyclo[2.2.2]octane in water were found by means of pulsed field gradient NMR spectroscopy. Effects of surfactant structure on critical micelle concentrations, hydrodynamic radii, and aggregation numbers of the micelles were discussed (available in Russian, English version is to be available soon)
Journal of Molecular Liquids, 2015
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2014
Oximes are among the most powerful organic supernucleophiles demonstrating high efficiency in the... more Oximes are among the most powerful organic supernucleophiles demonstrating high efficiency in the acyl transfers, including cleavage of the toxic organophosphorus compounds. In the reaction of oximolysis of acyl substrates, is of great importance to reach high observed reaction rates as well as to yield an ability of the system to act as a nucleophilic catalyst (turnover) which would provide the efficient decomposition of the large amounts of an acyl substrate. A detailed study of the reaction of supernucleiphilic reagent, 1-methyl-4-(hydroxyiminometyl)pyridinium iodide (4-pam), with 4-nitrophenyl acetate (pnpa) was carried out. Concentration dependences and ph-dependences were investigated. Using the different ratios of pnpa:4-pam, a kinetic model of the overall process was proposed, rate constants for the each stage were found. Effect of the stable gem-diol (chloral hydrate and hydrated 1- methyl-4-(oxyiminomethyl)pyridinium iodide) on the reaction rate was analyzed. Analysis of t...
Organic & biomolecular chemistry, Jan 19, 2015
Owing to the rising threats of neurotoxic organophosphosphorus compounds, facile and efficient de... more Owing to the rising threats of neurotoxic organophosphosphorus compounds, facile and efficient decontamination systems are required. Since the last few decades, the search for promising α-nucleophiles for straightforward and eco-friendly decontamination reactions using α-nucleophiles has been considerably boosted up. Among these, hydroxamic acids have been widely studied due to their potential α-nucleophilicity towards carbon and phosphorus based esters. This account summarizes our research on α-nucleophilicity of hydroxamate ions in water and micelles towards esterolytic reactions. Efforts of our group in the last few years have been collectively judged and compared with the crucial findings of researchers in the relevant field. The present article sheds light on the rich chemistry of the hydroxamate ion as a perfect candidate to degrade organophosphorus esters (i.e. nerve agents, pesticides and their simulants) in water, in micelles of conventional surfactants, and in functionaliz...
Journal of Physical Organic Chemistry, 2013
Kinetic studies of the reactions of tertiary oximes (monoisonitroso acetone; MINA and butane 2,3 ... more Kinetic studies of the reactions of tertiary oximes (monoisonitroso acetone; MINA and butane 2,3 dione monooxime; BDMO) with some carboxylate (p-nitrophenyl acetate and p-nitrophenyl benzoate), phosphate (p-nitrophenyl diphenyl phosphate and bis (2,4-dinitrophenyl) phosphate) and sulfonate (p-nitrophenyl p-toluene sulphonate) esters in gemini surfactants have been conducted. The observed first-order rate constant versus surfactant profiles show micelle-assisted bimolecular reactions involving interfacial ion exchange between bulk aqueous media and micellar pseudophase. Experimental results showed that MINA exhibited better nucleophilic activity towards ester cleavage than BDMO. Pseudophase model has been applied in order to determine micellar second-order rate constants and binding constants. /journal/poc Reaction conditions: [Substrate] = 0.5 Â 10 À4 M, [MINA] = 0.5 Â 10 À3 M, KCl = 0.1 M, pH = 9.0, Temp. = 27 C B. GUPTA ET AL.
Journal of Colloid and Interface Science, 2014
The surface properties of some families of cationic two-headed surfactants based on a pentaerythr... more The surface properties of some families of cationic two-headed surfactants based on a pentaerythritol backbone are described. The compounds have the following general structure (1), where R 0 are head groups and R are linear alkyl groups ranging from octyl to tetradecyl. The syntheses of these compounds has been published in detail previously. Critical micelle concentrations (cmc values) of these two-headed surfactants have been determined and compared to conventional ionic surfactants and gemini surfactants of similar structure. In addition, the surface activity of these two-headed surfactants, expressed as the C 20 value and the surface tension at the cmc, have been determined. Transmission electron microscopy has been used to examine the morphology of the aggregates formed by these amphiphiles. In general, when compared to conventional ionic and two-headed surfactants, these new two-headed surfactants exhibit a remarkable efficiency in the tendency to self-assemble and are significantly more surface active than their conventional counterparts.
Magnetochemistry, Oct 21, 2020
We report Peacock-Weakley complexes, Na 9 [Ln(W 5 O 18) 2 ]•35H 2 O, formed with Tm(III), 1, and ... more We report Peacock-Weakley complexes, Na 9 [Ln(W 5 O 18) 2 ]•35H 2 O, formed with Tm(III), 1, and Yb(III), 2. Their syntheses, physico-chemical characterizations, crystal structures, and magnetic properties are described. Ab initio calculations are also reported. These polyoxometalate (POM) complexes were obtained using original synthetic conditions where acidification was performed with a stoichiometric amount of nitric acid to an acidity of Z = ν(H +)/ν(WO 4 2-) = 8/10 = 0.80. Both the Tm(III) and Yb(III) derivatives were found to exhibit field-induced slow relaxation of their magnetization likely controlled by Raman and Orbach relaxation processes. 1 is a rare example of a Tm(III)-based single-molecule magnet (SMM) and is a consequence of the oblate tetragonal anti-prismatic symmetry of the coordination sphere.
Molecules
Novel composite self-disinfecting films of polylactic acid (PLA) filled with nanosized particles ... more Novel composite self-disinfecting films of polylactic acid (PLA) filled with nanosized particles of double sodium–copper(II) paratungstate B Na2Cu3(CuOH)2[W12O40(OH)2]·32H2O (POM) were developed. The solvent casting (POM/PLA film) and solvent-free melt extrusion methods (Extr. POM/PLA film) were applied for film preparation. The copper (II) ion release to water from both types of the films after 10 days at different temperatures demonstrated that the PLA matrix acts as a diffusion barrier, and the resulting concentration of released copper in water at room temperature remained low, at 0.79% for POM/PLA film and 0.51% for Extr. POM/PLA film. The POM-containing films reveals a significant inhibitory effect against E. coli ATCC 25922 in the agar diffusion test. The numbers of CFUs in washes of the films after incubation for 24 h were found to be 3.6 log CFU mL–1 (POM/PLA film) and 4.1 log CFU mL–1 (Extr. POM/PLA film). The films combine the antibacterial properties of POM and a bio-bas...
Russian Journal of Organic Chemistry, 2012
Processes of cleavage of 4-nitrophenyl esters of diethylphosphoric, diethylphosphonic, and 4-tolu... more Processes of cleavage of 4-nitrophenyl esters of diethylphosphoric, diethylphosphonic, and 4-toluenesulfonic acids were investigated occurring in micelles of surfactants containing supernucleophilic oximate fragment and on their analogs not forming micelles in water. At transferring the reaction from water into the micelles of functional surfactants the reaction accelerates 10 2-10 3 times. This acceleration is caused by the concentration of the substrate, for the nucleophilicity of the oximate fragment changes insignifi cantly. The reactivity of the functional surfactants is described by the Brønsted dependence with a break, its character is analogous to the dependence of the oximes non-forming micelles.
Bioresource Technology, 2020
Lignocellulosic biomass is the most plentiful renewable biomolecule and an alternative bioresourc... more Lignocellulosic biomass is the most plentiful renewable biomolecule and an alternative bioresource for the production of biofuels and biochemicals in biorefineries. But biomass recalcitrance is a bottleneck in their usage, thus necessitating their pretreatment for hydrolysis. Most pretreatment technologies, result in toxic by-products or have lower yield. Ionic liquids (ILs) have successfully advanced as 'greener and recyclable' alternatives to volatile organic solvents for lignocellulosic biomass dissolution. This review covers recent developments made in usage of IL-based techniques with focus on biomass breakdown mechanism, process parameter design, impact of cation and anion groups, and the advantageous impact of ILs on the subsequent processing of the fractionated biomass. Progress and barriers for large-scale commercial usage of ILs in emerging biorefineries were critically evaluated using the principles of economies of scale and green chemistry in an environmentally sustainable way.
A series of L-phenylalanine ionic liquids (ILs), L-tyrosine ILs, tertiary amino analogues and pro... more A series of L-phenylalanine ionic liquids (ILs), L-tyrosine ILs, tertiary amino analogues and proposed transformation products (PTPs) have been synthesised. Antimicrobial toxicity data, as part of the green chemistry metrics evaluation and to supplement preliminary biodegradation studies, was determined for ILs, tertiary amino analogues and PTPs. Good to very good overall yields (76 to 87%) for the synthesis of 6 ILs from L-phenylalanine were achieved. A C2-symmetric IL was prepared from TMS-imidazole in a one-pot two-step method in excellent yield (91%). Synthesis of the L-tyrosine IL derivatives utilised a simple protection group strategy by using an extra equivalent of the bromoacetyl bromide reagent. Improvements in the synthesis of the α-bromoamide alkylating reagent from L-phenylalanine were achieved, directed by green chemistry metric analysis. A solvent switch from dichloromethane to THF is described, however the yield was 15% lower. Antimicrobial activity testing of L-phenylalanine ILs, L-tyrosine ILs, tertiary amino analogues and PTPs, against 8 bacteria and 12 fungi strains, showed that no compound had a high antimicrobial activity, apart from an L-proline analogue. In this exceptional case, the highest toxicity (IC95 = 125 and 250 μM) was observed towards the two Gram positive strains Staphylococcus aureus and Staphylococcus epidermidis respectively. High antimicrobial activity was not found for the other bacteria or fungi strains screened. The limitations of the antimicrobial activity study is discussed in relation to SAR studies. Preliminary analysis of biodegradation data (Closed Bottle Test, OECD 301D) is presented. The pyridinium IL derivative is the preferred green IL of the series based on synthesis, toxicity and biodegradation considerations. This work is a joint study with Kümmerer and co-workers and the PTPs were selected as target compounds based on concurrent biodegradation studies by the Kümmerer group. For the comprehensive biodegradation and transformation product analysis see the accompanying paper.
We report on a new approach for creating water-soluble functionalized vesicles employing N-alkyl-... more We report on a new approach for creating water-soluble functionalized vesicles employing N-alkyl-3-boronopyridinium triflates (alkyl = Me, C 12 H 25 , C 16 H 33) as sensors for monosaccharides. The nanoaggregate properties were studied by means of DLS, TEM, high-resolution 1 H NMR, and the solvatochromic dyes Reichardt's betaine and Methyl Orange. The vesicles were shown to have 30−200 nm diameters depending on the amphiphile chain length. Diol binding to the vesicles was studied by steady-state fluorescence and UV−vis using Alizarin Red S as a probe in the solution at pH 7.4 in the presence and in the absence of D-glucose and D-fructose. Strong sensing ability of boronic acid functional moieties in the order D-fructose > D-glucose was demonstrated, and apparent binding constants were estimated.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2016
ACS Sustainable Chemistry & Engineering, 2016
Journal of Surfactants and Detergents, 2016
Russian Journal of Physical Chemistry B
Russian Journal of Organic Chemistry
Russian Chemical Bulletin
Effect of the spacer structure (linear, cyclic, bicyclic) and the presence of dissymmetry of alky... more Effect of the spacer structure (linear, cyclic, bicyclic) and the presence of dissymmetry of alkyl fragments in the series of dicationic dimeric (gemini) surfactants on the ability to form thermotropic liquid crystals and micellar properties was investigated. The transitions crystals – thermotropic LC – isotropic solution were studied using methods of differential scanning calorimetry and polarized optical microscopy. Self-diffusion coefficients of the micelles and monomers of dicationic dialkyl derivatives of 1,4-diazabicyclo[2.2.2]octane in water were found by means of pulsed field gradient NMR spectroscopy. Effects of surfactant structure on critical micelle concentrations, hydrodynamic radii, and aggregation numbers of the micelles were discussed (available in Russian, English version is to be available soon)
Journal of Molecular Liquids, 2015
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2014
Oximes are among the most powerful organic supernucleophiles demonstrating high efficiency in the... more Oximes are among the most powerful organic supernucleophiles demonstrating high efficiency in the acyl transfers, including cleavage of the toxic organophosphorus compounds. In the reaction of oximolysis of acyl substrates, is of great importance to reach high observed reaction rates as well as to yield an ability of the system to act as a nucleophilic catalyst (turnover) which would provide the efficient decomposition of the large amounts of an acyl substrate. A detailed study of the reaction of supernucleiphilic reagent, 1-methyl-4-(hydroxyiminometyl)pyridinium iodide (4-pam), with 4-nitrophenyl acetate (pnpa) was carried out. Concentration dependences and ph-dependences were investigated. Using the different ratios of pnpa:4-pam, a kinetic model of the overall process was proposed, rate constants for the each stage were found. Effect of the stable gem-diol (chloral hydrate and hydrated 1- methyl-4-(oxyiminomethyl)pyridinium iodide) on the reaction rate was analyzed. Analysis of t...
Organic & biomolecular chemistry, Jan 19, 2015
Owing to the rising threats of neurotoxic organophosphosphorus compounds, facile and efficient de... more Owing to the rising threats of neurotoxic organophosphosphorus compounds, facile and efficient decontamination systems are required. Since the last few decades, the search for promising α-nucleophiles for straightforward and eco-friendly decontamination reactions using α-nucleophiles has been considerably boosted up. Among these, hydroxamic acids have been widely studied due to their potential α-nucleophilicity towards carbon and phosphorus based esters. This account summarizes our research on α-nucleophilicity of hydroxamate ions in water and micelles towards esterolytic reactions. Efforts of our group in the last few years have been collectively judged and compared with the crucial findings of researchers in the relevant field. The present article sheds light on the rich chemistry of the hydroxamate ion as a perfect candidate to degrade organophosphorus esters (i.e. nerve agents, pesticides and their simulants) in water, in micelles of conventional surfactants, and in functionaliz...
Journal of Physical Organic Chemistry, 2013
Kinetic studies of the reactions of tertiary oximes (monoisonitroso acetone; MINA and butane 2,3 ... more Kinetic studies of the reactions of tertiary oximes (monoisonitroso acetone; MINA and butane 2,3 dione monooxime; BDMO) with some carboxylate (p-nitrophenyl acetate and p-nitrophenyl benzoate), phosphate (p-nitrophenyl diphenyl phosphate and bis (2,4-dinitrophenyl) phosphate) and sulfonate (p-nitrophenyl p-toluene sulphonate) esters in gemini surfactants have been conducted. The observed first-order rate constant versus surfactant profiles show micelle-assisted bimolecular reactions involving interfacial ion exchange between bulk aqueous media and micellar pseudophase. Experimental results showed that MINA exhibited better nucleophilic activity towards ester cleavage than BDMO. Pseudophase model has been applied in order to determine micellar second-order rate constants and binding constants. /journal/poc Reaction conditions: [Substrate] = 0.5 Â 10 À4 M, [MINA] = 0.5 Â 10 À3 M, KCl = 0.1 M, pH = 9.0, Temp. = 27 C B. GUPTA ET AL.
Journal of Colloid and Interface Science, 2014
The surface properties of some families of cationic two-headed surfactants based on a pentaerythr... more The surface properties of some families of cationic two-headed surfactants based on a pentaerythritol backbone are described. The compounds have the following general structure (1), where R 0 are head groups and R are linear alkyl groups ranging from octyl to tetradecyl. The syntheses of these compounds has been published in detail previously. Critical micelle concentrations (cmc values) of these two-headed surfactants have been determined and compared to conventional ionic surfactants and gemini surfactants of similar structure. In addition, the surface activity of these two-headed surfactants, expressed as the C 20 value and the surface tension at the cmc, have been determined. Transmission electron microscopy has been used to examine the morphology of the aggregates formed by these amphiphiles. In general, when compared to conventional ionic and two-headed surfactants, these new two-headed surfactants exhibit a remarkable efficiency in the tendency to self-assemble and are significantly more surface active than their conventional counterparts.