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  • 1.
    Ahmed, Mukhtiar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Bhowmick, Sourav
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Johansson, Patrik
    Materials Physics, Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Ionic Liquids and Electrolytes with Flexible Aromatic Anions2023Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 29, nr 41, artikel-id e202301000Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Five new n-tetrabutylphosphonium (P4444)+ cation based ionic liquids (ILs) with oligoether substituted aromatic carboxylate anions have been synthesized. The nature and position of the oligoether chain affect thermal stability (up to 330 ºC), phase behaviour (Tg < -55 ºC) and ion transport. Furthermore, with the aim of application in lithium batteries, electrolytes were created for two of the ILs by 10 mol% doping using the corresponding Li-salts. This affects the ion diffusion negatively, from being higher and equal for cations and anions to lower for all ions and unequal. This is due to the stronger ionic interactions and formation of aggregates, primarily between the Li+ ions and the carboxylate group of the anions. Electrochemically, the electrolytes have electrochemical stability windows up to 3.5 V, giving some promise for battery application.

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  • 2.
    Ahmed, Mukhtiar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Johansson, Patrik
    Materials Physics, Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Luleå University of Technology Chemistry of Interfaces Luleå University of Technology 97187 Luleå SWEDEN.
    Pyrrolidium‐ and Imidazolium‐Based Ionic Liquids and Electrolytes with Flexible Oligoether Anions2024Ingår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641Artikel i tidskrift (Refereegranskat)
  • 3.
    Ahmed, Mukhtiar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rao, Soniya S.
    Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Johansson, Patrik
    Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Aromatic Heterocyclic Anion Based Ionic Liquids and Electrolytes2023Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 25, nr 4, s. 3502-3512Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Five new ionic materials comprising fluorine-free aromatic heterocyclic anions based on pyridine and pyrazine combined with a common n-tetrabutylphosphonium cation, (P4444)+, result in two room temperature ionic liquids (RTILs), one semi-solid, and two organic ionic plastic crystals (OIPCs) with melting points >20 °C. The OIPCs showed a plastic crystalline phase, multiple solid–solid transitions, and plastic crystalline and melt phases. For both the neat RTILs and the Li+ conducting electrolytes, the nature and strength of the ion–ion interactions mainly depend on the position of the nitrogen atom with respect to the carboxylate group in the anions. Furthermore, for the RTILs the ionic conductivity is effected by the electronic structure and flexibility of the ions and the anions diffuse faster than the (P4444)+ cation, but are slowed down in the electrolytes due to the strong electrostatic interactions between the carboxylate group of the anions and the Li+, as shown both experimentally and computationally. Overall, this study describes the effect of structural tuning of aromatic anions on the ion–ion interactions and introduces new ionic materials with promising properties to be used as solid and liquid electrolytes in energy storage devices.

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  • 4.
    Antzutkin, Oleg
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Wong, Alan
    University of Warwick.
    Baldus, Johanna Becker
    University of Warwick.
    Hung, Ivan
    University of Warwick.
    Kukol, A.
    University of Warwick.
    Brown, Steven P.
    University of Warwick.
    Smith, Mark E.
    University of Warwick.
    Dupree, Ray
    University of Warwick.
    Exploring solid-state 17O NMR to distinguish secondary structures in Alzheimer's Aβ fibrils2009Konferensbidrag (Refereegranskat)
  • 5.
    Antzutkin, Oleg
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Filippov, Andrei
    Wong, Alan
    University of Warwick.
    Baldus, Johanna
    University of Warwick.
    Hung, Ivan
    University of Warwick.
    Kukol, A.
    University of Warwick.
    Brown, Steven P.
    University of Warwick.
    Smith, Mark E.
    University of Warwick.
    Dupree, Ray
    University of Warwick.
    Exploring solid-state 17O NMR to distinguish secondary structures in Alzheimer's Aβ fibrils2009Ingår i: Euromar 2009: Magnetics Resonance Conference, 5-9 July 2009, Göteborg, Sweden. Programme and Abstract Book, 2009, s. 107-Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    It has been shown by a large number of studies that Alzheimer's disease (AD) amyloid-β-peptide (Aβ) deposits contribute directly to the disease's progressive neurodegeneration. Aggregation cascade for Aβ peptides, its relevance to neurotoxicity in the course of AD, various factors modulating Aβ aggregation kinetics and experimental methods useful for these studies were recently discussed [1]. Results of Tycko and co-workers point at neurotoxicity in vitro of the two different types of Alzheimer's amyloid fibrils dispersed by ultrasonication into small fragments [2]. The high toxicity of Aβ oligomers in vitro has been discussed by Stege et. al who have found that the molecular chaperone αB-crystallin prevents Aβ from forming amyloid fibrils but nevertheless enhances Aβ toxicity [3]. Glabe and co-workes successfully prepared antibodies for Aβ oligomers and small spherical aggregates using nanogold technology [4]. They also have shown that these antibodies decrease toxicity of Aβ for SH-SY5Y human neuroblastoma cell cultures in vitro [4]. In this concern both structure of Aβ-oligomers/fibrils and the specific  interaction (aggregation/fusion) of Aβ peptides with nerve cell membranes is of a particular importance [5].We explore Solid-State 17O NMR on selectively 17O,13C,15N-labeled Aβ(1-40), Aβ(11-25) and Ac-Aβ(16-22)-NH2 peptides to distinguish a parallel and anti-parallel β-sheet secondary structures in β-NH2 peptides to distinguish a parallel and anti-parallel β-sheet secondary structures in amyloid fibrils. Aβ(1-40) fibrils form in-registry parallel β-sheets [6], while Aβ(11-25) [7] and Ac-Aβ(16-22)-NH2 [8] form different anti-parallel β-sheet structures, which were previously identified β-NH2 [8] form different anti-parallel β-sheet structures, which were previously identified by 13C multiple-quantum and 13C{15N} REDOR solid-state NMR. In our unpublished work presented here it was found that 17O NMR chemical shifts are sensitive to the type of the secondary structure, i. e. a parallel vs. an anti-parallel β-sheet structures, while the quadrupolar parameters of 17O nuclei unexpectedly do not vary beyond the error limits in the simulated lineshapes of both fibrillized and unfibrillized peptide systems. Results of more advanced solidstate NMR techniques to measure heteronuclear distances, 15N{17O}-REAPDOR, 15N{17O}-TRAPDOR and 17O{15N}-REDOR on selectively 17O-Val18 and 15N-Phe20 labeled Ac-Aβ(16-22)-NH2 fibrils will be also discussed. These novel solid-state NMR experiments will provide additional tools for measuring hydrogen bonding in different secondary structures of peptides in amyloid fibrils.[1.] O.N.Antzutkin, Magn. Reson. Chem. 42 (2004) 231-246; [2.] A.Petkova et al. Science 307 (2005) 262-265; [3.] G.J.J.Stege, et al. Biochem. Biophys. Res. Comm., 262 (1999) 152-156;[4.] R.Kayed et al. Science, 300 (2003) 486-489; [5.] M.Bokvist, et al. J. Mol. Biol. 335 (2004) 1039-1049; [6.] O.N. Antzutkin, et al. Proc. Nat. Acad. Sci, U.S.A., 97 (2000) 13045-13050;[7.] A.T. Petkova, et al. J. Mol. Biol., 335 (2004) 247-260;[8.] J.J. Balbach, Y. (2000) 13045-13050; [9] A.T. Petkova, (2004) 247-260; [10] J.J. Balbach, Y.Ishii, O.N. Antzutkin, et al. Biochemistry 39 (2000) 13748-13759.

  • 6.
    Antzutkin, Oleg
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Iuga, Dino
    Department of Physics, Warwick University, Coventry.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kelly, Robert T.
    Department of Physics, Warwick University, Coventry.
    Becker-Baldus, Johanna
    Department of Physics, Warwick University, Coventry.
    Brown, Steven P.
    Department of Physics, Warwick University, Coventry.
    Dupree, Ray
    Department of Physics, Warwick University, Coventry.
    Hydrogen bonding in Alzheimer’s amyloid-β fibrils probed by 15N{17O} REAPDOR solid-state NMR spectroscopy2012Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 51, nr 41, s. 10289-10292Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An exclusive label: 15N{17O} REAPDOR NMR was used to validate intermolecular C17O⋅⋅⋅H15N hydrogen bonding in Ac-Aβ(16–22)-NH2 (see scheme) and Aβ(11–25) amyloid fibrils, which are associated with Alzheimer’s disease, by selectively labeling them with 17O and 15N. This method was effective for confirming the structure of these fibrils, and could be useful for a number of other biological samples.

  • 7.
    Antzutkin, Oleg
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Iuga, Dinu
    Department of Physics, Warwick University, Coventry.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kelly, Robert T.
    Department of Physics, Warwick University, Coventry.
    Becker-Baldus, Johanna
    Department of Physics, Warwick University, Coventry.
    Brown, Steven P.
    Department of Physics, Warwick University, Coventry.
    Dupree, Ray
    Department of Physics, Warwick University, Coventry.
    Hydrogen bonding in Alzheimer’s amyloid-β fibrils probed by 15N{17O} REAPDOR solid-state NMR spectroscopy2012Ingår i: Angewandte Chemie, ISSN 0044-8249, Vol. 124, nr 41, s. 10435-10438Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nach selektiver Markierung mit 17O und 15N wurden mithilfe von 15N{17O}-REAPDOR-NMR-Spektroskopie intermolekulare C17O⋅⋅⋅H15N-Wasserstoffbrücken in Ac-Aβ(16–22)-NH2- (siehe Schema) und Aβ(11–25)-Amyloidfibrillen untersucht, die mit der Alzheimer-Krankheit in Verbindung gebracht werden. Die Methode, die eine Bestätigung für die Struktur dieser Fibrillen lieferte, könnte auch im Zusammenhang mit anderen biologischen Proben nützlich sein.

  • 8.
    Arkhipov, Victor P.
    et al.
    Kazan National Research Technological University, 420015 Kazan, Russia.
    Arkhipov, Ruslan
    Kazan Federal University, 420008 Kazan, Russia.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Medical and Biological Physics, Kazan State Medical University, 420012 Kazan, Russia.
    Micelles of Oxyethylated Isononylphenols in Aqueous Solutions and Hydrophilic–Lipophilic Balance2020Ingår i: ACS Omega, E-ISSN 2470-1343, Vol. 5, nr 43, s. 28224-28232Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have measured the self-diffusion coefficients and calculated the effective hydrodynamic radii of micelles of ethoxylated isononylphenols in aqueous solutions in the presence of sodium chloride, as well as in their binary mutual mixtures, when approaching cloudy conditions. These cloudy conditions were created by an increase in temperature, a change in the concentration of an electrolyte in the solution, or a mutual ratio of neonols in their binary mixtures. The results are discussed within the concept of the hydrophilic–lipophilic balance.

  • 9.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, Kazan 420015, Russian Federation.
    Arkhipov, Ruslan
    Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rhamnolipid Biosurfactant: Use for the Removal of Phenol from Aqueous Solutions by Micellar Solubilization2023Ingår i: ACS Omega, E-ISSN 2470-1343, Vol. 8, nr 33, s. 30646-30654Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Selective measurements of the self-diffusion coefficients of molecules of the biological surfactant rhamnolipid (RL) in individual aqueous solutions and in solutions with phenol as a solubilizate were carried out by nuclear magnetic resonance (NMR) diffusometry. Based on the obtained results, the solubilization characteristics of RLs were calculated. They are the fraction of solubilized phenol molecules, the phenol micelle-water distribution coefficient, the molar solubilization coefficient, the hydrodynamic radii of RL monomers and micelles, the aggregation numbers of micelles, and the solubilization capacity of micelles. Fraction of the solubilized phenol molecules increases and approaches 80-90% with increasing RL concentration. The solubilization capacity of the micelles increases from several units to 102 with an increase in both the concentration of RLs and the concentration of phenol in solution.

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  • 10.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, Kazan, Russian Federation.
    Arkhipov, Ruslan V.
    Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Dynamic and molecular association in premicellar aqueous solutions of dicarboxylate amino acid-based surfactant as studied by 1H NMR2022Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 60, nr 3, s. 359-368Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We examined a series of amino acid-based surfactants with two carboxylic groups separated by a spacer of one, two, or three carbon atoms with sodium and calcium counterions in the premicellar concentration region near the CMC. 1H NMR spectroscopy and NMR diffusometry techniques were used to study the local environment, association and translational dynamics of the surfactant’s molecules. We measured the self-diffusion coefficients of the micelles, calculated the effective hydrodynamic radii, and determined the temperature region in which the premicelles exist. With an increase in temperature from 295 to 335 K, the premicellar state of the surfactant is replaced by the monomeric state.  

  • 11.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, Kazan, Russian Federation.
    Arkhipov, Ruslan V.
    Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Kuzina, Natalia A.
    Department of Physics, Kazan National Research Technological University, Kazan, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russian Federation.
    Oxyethylated Isononylphenols in Carbon Tetrachloride2019Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 50, nr 12, s. 1381-1389Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Translational diffusion coefficients of ethoxylated isononylphenol molecules C9H19C6H4O(C2H4O)nH in carbon tetrachloride were measured by nuclear magnetic resonance diffusometry. The hydrodynamic radii of the molecules were determined within the framework of the Stokes–Einstein relation. We showed that ethoxylated isononylphenols in carbon tetrachloride do not form micelles, and the dependence of the diffusion coefficients and, accordingly, the hydrodynamic radii of the nonionic surfactants on the number of oxyethylene groups have a kink in the region n = 6–8.

  • 12.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, 420015 Kazan, Russian Federation.
    Arkhipov, Ruslan V.
    Institute of Physics, Kazan Federal University, 420008 Kazan, Russian Federation.
    Kuzina, Natalia A.
    Department of Physics, Kazan National Research Technological University, 420015 Kazan, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Study of the premicellar state in aqueous solutions of sodium dodecyl sulfate by nuclear magnetic resonance diffusion2021Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 59, nr 11, s. 1126-1133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Self‐diffusion coefficients of sodium dodecyl sulfate (SDS) were measured in aqueous solutions in the premicellar range of the SDS concentrations 7‐34.7 mM and temperatures 30‐900C. Average effective hydrodynamic radii and aggregation numbers of SDS in the premicellar region were determined. At C < CMC at all temperatures, the SDS solution is the solution of monomers. At C > CMC the increase of temperature leads to decrease in the effective hydrodynamic radii and the average aggregation numbers. At C >> CMC, it is impossible to reach the monomeric state by increasing the temperature.  

  • 13.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, 420015, Kazan, Russian Federation.
    Arkhipov, Ruslan V.
    Institute of Physics, Kazan Federal University, 420008, Kazan, Russian Federation.
    Kuzina, Natalia
    Department of Physics, Kazan National Research Technological University, 420015, Kazan, Russian Federation.
    Petrova, Ekaterina V.
    Department of Analytical Chemistry, Kazan National Research Technological University, 420015, Kazan, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Aggregation Properties of Triton X-100 in a Mixture of Ordinary and Heavy Water2023Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 54, nr 3, s. 415-425Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic and aggregation properties of Triton X-100 in a mixture of ordinary and heavy water in a wide temperature range from room temperature to the cloud point and above were studied. The ratio of ordinary and heavy water was calculated in such a way as to ensure equal densities of Triton X-100 and the water mixture. This made it possible to exclude the effects of sedimentation and study the evolution of Triton X-100 micelles and aggregates, without complication by the effects of spatial phase separation above the cloud point. Self-diffusion coefficients of Triton X-100 molecules were measured by NMR, and the effective hydrodynamic radii of micelles and aggregates were calculated using the Stokes-Einstein relation. The anomalous temperature behavior of the diffusion coefficient of Triton X-100 molecules is explained by changes in the sizes of diffusing objects during their evolution from micelles to dehydrated aggregates below the cloud point and by changes in the sizes of aggregates above the cloud point. The results of the NMR studies are confirmed by data obtained by dynamic light scattering.

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  • 14.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, 420015, Kazan, Russian Federation.
    Arkhipov, Ruslan V.
    Institute of Physics, Kazan Federal University, 420008 Kazan, Russian Federation.
    Petrova, Ekaterina V.
    Department of Analytical Chemistry, Kazan National Research Technological University, 420015, Kazan, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Abnormal diffusion behavior and aggregation of oxyethylated alkylphenols in aqueous solutions near their cloud point2022Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 358, artikel-id 119203Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have investigated solutions of oxyethylated alkylphenols (neonols) in a mixture of ordinary and heavy water with equal densities of the neonols and the aqueous mixture. The equal densities allow exclusion of sedimentation effects and study of the evolution of micelles and neonol aggregates in the range from room temperature to above the cloud point. The self-diffusion coefficients of neonols were measured by NMR and the effective hydrodynamic radii of micelles and neonol aggregates were calculated using the Stokes-Einstein relation. An abnormal decrease in neonols diffusion coefficients occurred when the system approached the cloud point, while an abnormal increase in the diffusion coefficients occurred at temperatures above the cloud point. We explained the abnormal temperature behavior of the diffusion coefficients of neonols by changes in the size of the diffusing objects from the spherical and spherocylindrical micelles to dehydrated aggregates and the destruction of micelles by thermal motion and by formation of aggregates with sizes of the order 102 nm at temperatures above the cloud point. Conclusions about the increase in the hydrodynamic radii of the micelles with increasing temperature up to the cloud point and about the formation of dehydrated aggregates above the cloud point are confirmed by the results of DLS studies.

  • 15.
    Arkhipov, Victor P.
    et al.
    Department of Physics Kazan National Research Technological University Kazan 420015 Russian Federation.
    Arkhipov, Ruslan V.
    Institute of Physics Kazan Federal University Kazan 420008 Russian Federation.
    Petrova, Ekaterina V.
    Department of Analytical Chemistry Kazan National Research Technological University Kazan 420015 Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Micellar and solubilizing properties of rhamnolipids2023Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 61, nr 6, s. 345-355Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We studied the micellar and solubilizing properties of aqueous solutions of unfractionated rhamnolipids produced by Pseudomonas aeruginosa. We used nuclear magnetic resonance (NMR) diffusometry, dynamic light scattering, and conductometry to measure the critical micelle concentration (CMC) of rhamnolipid solutions and determined the effective hydrodynamic radii of rhamnolipid monomers and micelles. Based on selective measurements of the self-diffusion coefficients of molecules, performed by NMR diffusometry, the solubilizing properties of rhamnolipids were studied depending on their concentration in solution; aromatic hydrocarbons, benzene, toluene, ethylbenzene, and para-xylene were taken as solubilizates. On the basis of the measurement results, we estimated the distribution coefficient of the solubilizate between the micellar (solubilized) and free (in the aqueous phase) states and the solubilizing capacity of rhamnolipid micelles.

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  • 16.
    Arkhipov, Victor P.
    et al.
    Kazan National Research Technological University.
    Bogdanova, Svetlana A.
    Kazan National Research Technological University.
    Idiyatullin, Zhamil Sh.
    Kazan National Research Technological University.
    Lunev, Ivan V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Dynamic and structural properties of oxyethylated isononylphenols2016Ingår i: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 26, nr 4, s. 355-357Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Diffusion coefficients, dielectric relaxation times and refraction coefficients were measured, and activation energies of translational and rotational mobilities were determined for a series of oxyethylated phenols (neonols AF9-n) p-C9H19C6H4-O(CH2CH2O)nH, n = 4, 6, 8, 9, 10, 12, at different temperatures. The results demonstrated the existence of contraction and transition phenomena that changed the structure of neonol molecules at n ∼ 9 from a zigzag to a meander form.

  • 17.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, Kazan, Russia.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russia.
    The cloud point of aqueous solutions of ethoxylated monoalkylphenols in the individual state and in the presence of electrolytes2018Ingår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 39, nr 10, s. 1442-1446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The cloud points tcp of aqueous solutions of ethoxylated monoalkylphenols, AF9-n (n = 8,9,10,12), were measured in the concentration (C) range of 0.25-40 wt.%. tcp increased as C decreased at C < 1 wt.%. At 1 < С < 10 wt.%, tcp changed insignificantly; Δtcp/tcp did not exceed 5%. Solutions transformed into the gel state at С > 10-20 wt.% and tcp sharply increased. The dependence of tcp on the length of the oxyethylene chains of ethoxylated nonylphenols at C = 1 wt.% can be described by the equation tcp = b·ln(n-n0), where n0 = 6. The cloud points of aqueous solutions (C = 1 wt.%) of the ethoxylated nonylphenols were measured at different concentrations of NaI, NaCl, NaF, Na2CO3, and Na2SO4 salts. For all of these solutions, tcp decreased in the presence of NaCl, NaF, Na2CO3, Na2SO4 and increased in the presence of NaI. To describe the dependence of tcp on the salt concentration, the equation was suggested, where and tcp are the cloud points of a neat aqueous solution of ethoxylated nonylphenols and of the solution in the presence of electrolytes, respectively.

  • 18.
    Arkhipov, Victor P.
    et al.
    Kazan National Research Technological University.
    Idiyatullin, Zamil Sh.
    Kazan National Research Technological University.
    Gnezdilov, Oleg I.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Petrova, Ekaterina V.
    Kazan National Research Technological University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Molecular self-diffusion and micellar structure in the aqueous solutions of AF9-10 ethoxylated isononylphenol near a cloud point2014Ingår i: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 24, nr 5, s. 266-268Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sizes of micelles and compositions of aggregates in the aqueous solutions of the nonionic surfactant oxyethylated monoalkyl phenol (neonol AF9-10) were determined by NMR spectroscopy, NMR diffusometry and dynamic light scattering in a wide range of tem- peratures near the cloud point. The cloud point extraction of phenol from aqueous solutions by the surfactant AF9-10 was performed.

  • 19.
    Arkhipov, Victor P.
    et al.
    Kazan National Research Technological University.
    Idiyatullin, Zhamil Sh
    Kazan National Research Technological University.
    Potapova, Elisaveta
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Micelles and aggregates of oxyethylated isononylphenols and their extraction properties near cloud point2014Ingår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, nr 20, s. 5480-5487Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We used nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS) techniques to study the structural and dynamic properties of micellar solutions of nonionic surfactants of a homologous series of oxyethylated isononylphenols - C9H19C6H 4O(C2H4O)nH, where n = 6, 8, 9, 10, or 12 - in a wide range of temperatures, including cloud points. The radii of the micelles and aggregates, as well as their compositions at different concentrations of surfactant, were determined. Using aqueous phenol solutions as a model, we studied the process of cloud point extraction with oxyethylated isononylphenols

  • 20.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, 420015, Kazan, Russian Federation.
    Kuzina, Natalia A.
    Department of Physics, Kazan National Research Technological University, 420015, Kazan, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, 420012, Kazan, Russian Federation.
    Self-Diffusion Coefficients, Aggregation Numbers and the Range of Existence of Spherical Micelles of Oxyethylated Alkylphenols2021Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 52, nr 5, s. 607-617Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aggregation numbers were calculated based on measurements of the self-diffusion coefficients, the effective hydrodynamic radii of micelles and aggregates of oxyethylated alkylphenols in aqueous solutions. On the assumption that the radii of spherical micelles are equal to the lengths of fully extended neonol molecules, the limiting values of aggregation numbers corresponding to spherically shaped neonol micelles were calculated. The concentration and temperature ranges under which spherical micelles of neonols are formed were determined.

  • 21.
    Arkhipov, Victor
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Potapova, Elisaveta
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Micelle structure and molecular self-diffusion in isononylphenol ethoxylate–water systems2013Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 51, nr 7, s. 424-430Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The structure and dynamic properties of micellar solutions of nonionic surfactants of a series of isononylphenol ethoxylates, C9H19C6H4O(C2H4O)nH (where n = 6,8,9,10, and 12), were studied by NMR diffusometry, dynamic light scattering, and viscosimetry. The sizes of the micelles were determined for different surfactants and at different surfactant concentrations. The numbers of water molecules bound by a micelle and by one oxyethylene group of the surfactant were estimated

  • 22.
    Arkhipov, Viktor P.
    et al.
    Department of Physics, Kazan National Research Technological University, Kazan, Russian Federation.
    Arkhipov, Ruslan V.
    Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Idiyatullin, Zamil Sh.
    Department of Physics, Kazan National Research Technological University, Kazan, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Medical and Biological Physics, Kazan State Medical University, Kazan, Russian Federation.
    Dynamic and structural properties, cloud point of mixed micelles of oxyethylated isononylphenols2021Ingår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 42, nr 2, s. 278-285Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We measured the self-diffusion coefficients of mixed micelles formed in binary mixtures of oxyethylated isononylphenols (neonols) AF9-2,3,4,6,8,9,10,12 by NMR diffusometry in aqueous 1 wt% solutions. The effective hydrodynamic radii of the micelles were calculated using the Stokes-Einstein relation. Cloud points of these solutions were determined visually and the relation between the cloud point and the composition of the mixture was suggested. Extraction of phenol from the solutions at their cloud points was also studied.

  • 23.
    Becker-Baldus, Johanna
    et al.
    University of Warwick.
    Uldry, A-C
    Webber, A.L.
    Wong, Alan
    University of Warwick.
    Smith, Merk E.
    University of Warwick.
    Joyce, S.A.
    Yeats, J.R.
    Pickard, C.J.
    Dupree, Ray
    University of Warwick.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Probing NH-O hydrogen bonding by solid-state NMR: using 15N-17O dipolar and J-couplings2009Konferensbidrag (Refereegranskat)
  • 24.
    Bhattacharyya, Shubhankar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Russia.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    High CO2 absorption capacity by chemisorption at cations and anions in choline-based ionic liquids2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 46, s. 31216-31226Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of CO2 absorption on the aromaticity and hydrogen bonding in ionic liquids is investigated. Five different ionic liquids with choline based cations and aprotic N-heterocyclic anions were synthesized. Purity and structures of the synthesized ionic liquids were characterized by 1H and 13C NMR spectroscopy. CO2 capture performance was studied at 20 °C and 40 °C under three different pressures (1, 3, 6 bar). The IL [N1,1,6,2OH][4-Triz] showed the highest CO2 capture capacity (28.6 wt%, 1.57 mol of CO2 per mol of the IL, 6.48 mol of CO2 per kg of the ionic liquid) at 20 °C and 1 bar. The high CO2 capture capacity of the [N1,1,6,2OH][4-Triz] IL is due to the formation of carbonic acid (–OCO2H) together with carbamate by participation of the –OH group of the [N1,1,6,2OH]+ cation in the CO2 capture process. The structure of the adduct formed by CO2 reaction with the IL [N1,1,6,2OH][4-Triz] was probed by using IR, 13C NMR and 1H–13C HMBC NMR experiments utilizing 13C labeled CO2 gas. 1H and 13C PFG NMR studies were performed before and after CO2 absorption to explore the effect of cation–anion structures on the microscopic ion dynamics in ILs. The ionic mobility was significantly increased after CO2 reaction due to lowering of aromaticity in the case of ILs with aromatic N-heterocyclic anions.

  • 25.
    Bhattacharyya, Shubhankar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Insights into the Effect of CO2 Absorption on the Ionic Mobility of Ionic Liquids2016Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, nr 41, s. 28617-28625Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate a comparative effect of CO2 absorption on the ionic mobility of two choline based ionic liquids comprising two different anions such as threonine and imidazole. The synthesized ionic liquids were characterized using 1H and 13C NMR and other spectroscopic techniques. By keeping a common cation and changing the anion from threonine to imidazole both the viscosity and density reduced drastically. We found that [N1,1,6,2OH][Imi] exhibits the highest CO2 capture capacity at 20 °C of 5.27 mol of CO2 per kg of ionic liquid (1.27 mol of CO2 per mol of ionic liquid, 23.26 wt% of CO2) whereas [N1,1,6,2OH][Threo] exhibits 3.6 mol of CO2 per kg of ionic liquid (1.05 mol of CO2 per mol of ionic liquid, 15.87 wt% of CO2). The activation energy for diffusion is calculated using the Vogel-Fulcher-Tamman (VFT) equation in the form of diffusivity. It was found that the activation energy for the diffusion of [N1,1,6,2OH][Threo] is ∼10 times higher than that of [N1,1,6,2OH][Imi]. 1H diffusion NMR data revealed that the diffusivity of [N1,1,6,2OH][Imi] is increased after CO2 absorption whereas a decrease in diffusivity was observed in the case of [N1,1,6,2OH][Threo]. This anomalous behavior of [N1,1,6,2OH][Imi] was further explained by using DFT calculations.

  • 26.
    Bhowmick, Sourav
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Ahmed, Mukhtiar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Loaiza, Laura C.
    Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Johansson, Patrik
    Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; ALISTORE-European Research Institute, CNRS FR 3104, Hub de l’Energie, 80039 Amiens, France.
    Ambient Temperature Liquid Salt Electrolytes2023Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 59, nr 18, s. 2620-2623Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alkali metal salts usually have high melting points due to strong electrostatic interactions and solvents are needed to create ambient temperature liquid electrolytes. Here, we report on six phosphate-anion-based alkali metal salts, Li/Na/K, all of which are liquids at room temperature, with glass transition temperatures ranging from −61 to −29 °C, and are thermally stable up to at least 225 °C. While the focus herein is on various physico-chemical properties, these salts also exhibit high anodic stabilities, up to 6 V vs. M/M+ (M = Li/Na/K), and deliver some battery performance – at elevated temperatures as there are severe viscosity limitations at room-temperature. While the battery performance arguably is sub-par, solvent-free electrolytes based on alkali metal salts such as these should pave the way for conceptually different Li/Na/K-batteries, either by refined anion design or by using several salts to create eutectic mixtures.

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  • 27.
    Bhowmick, Sourav
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Khan, Inayat Ali
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Physical and electrochemical properties of new structurally flexible imidazolium phosphate ionic liquids2022Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 24, nr 38, s. 23289-23300Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New structurally flexible 1-methyl- and 1,2-dimethyl-imidazolium phosphate ionic liquids (ILs) bearing oligoethers have been synthesized and thoroughly characterized. These novel ILs revealed high thermal stabilities, low glass transitions, high conductivity and wide electrochemical stability windows up to 6 V. Both anions and cations of 1-methyl-imidazolium ILs diffuse faster than the ions of 1,2-dimethyl-imidazolium ILs, as determined by pulsed field gradient nuclear magnetic resonance (PFG-NMR). The 1-methyl-imidazolium phosphate ILs showed relatively higher ionic conductivities and ion diffusivity as compare with the 1,2-dimethyl-imidazolium phosphate ILs. As expected, the diffusivity of all the anions and cations increases with an increase in the temperature. The 1-methyl-imidazolium phosphate ILs formed hydrogen bonding with the phosphate anions, the strength of which is decreased with increasing temperature, as confirmed by variable temperature 1H and 31P NMR spectroscopy. One of the representative IL, [EmDMIm][DEEP], presented a promising performance at elevated temperatures as an electrolyte in a supercapacitor composed of multiwall carbon nanotubes and activated charcoal (MWCNTs/AC) composite electrodes.

  • 28.
    Bhowmick, Sourav
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Tatrari, Gaurav
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Johansson, Patrik
    Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; ALISTORE-European Research Institute, CNRS FR 3104, Hub de l’Energie, 80039 Amiens, France.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Structurally Flexible Pyrrolidinium- and Morpholinium-based Ionic Liquid Electrolytes2023Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 25, nr 29, s. 19815-19823Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ion transport measures and details as well as physico-chemical and electrochemical properties are presented for a small set of structurally flexible pyrrolidinium (Pyrr) and morpholinium (Morph) cation-based ionic liquids (ILs), all with oligoether phosphate-based anions. All have high thermal stabilities, low glass transition temperatures, and wide electrochemical stability windows, but rather moderate ionic conductivities, whereas both the anions and the cations of the Pyrr-based ILs diffuse faster than those of the Morph-based ILs. Overall the former ILs have significantly more promise as high-temperature supercapacitor electrolytes, rendering a specific capacitance of 164 F g−1 at 1 mV s−1, a power density of 241 W kg−1 and a specific energy density of 30 Wh kg−1 at 90 °C in a symmetric graphite supercapacitor.

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  • 29.
    Blochin, Dimri S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Aganova, Oksana V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Yulmetov, Aidar R.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Gizatulin, Bulat L.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Afonin, Sergii
    Karlsruhe Institute of Technology.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of heptapeptide Glu-Ile-Leu-Asn-His-Met-Lys, a fragment of the HIV enhancer prostatic acid phosphatase, in aqueous and SDS micelle solutions2013Ingår i: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1033, s. 59-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Prostatic acid phosphatase (PAP) is a protein abundantly present in human seminal fluid. PAP plays important role in fertilization. Its 39-amino-acid fragment, PAP(248-286), is effective in enhancing infectivity of HIV virus. In this work, we determined the spatial structure in aqueous solution of a heptapeptide within the PAP fragment, containing amino acid residues 266-272 (Glu-Ile-Leu-Asn-His-Met-Lys). We also report the structure of the complex formed by this heptapeptide with sodium dodecyl sulfate micelles, a model of a biological membrane, as determined by 1H NMR spectroscopy and 2D NMR (TOCSY, HSQC-HECADE, NOESY) spectroscopy. Complex formation was confirmed by chemical shift alterations in the 1H NMR spectra of the heptapeptide, as well as by the signs and values of NOE effects. We also present a comparison of the spatial structure of Glu-Ile-Leu-Asn-His-Met-Lys in water and in complex with sodium dodecyl sulfate

  • 30.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Fayzullina, Adeliya R.
    Chemistry Institute, Kazan Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Karataeva, Farida Kh.
    Alexander Butlerov Institute of Chemistry, Kazan Federal University, Chemistry Institute, Kazan Federal University.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of fibrinopeptide B in water solution with DPC micelles by NMR spectroscopy2015Ingår i: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1102, s. 91-94Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fibrinopeptide B (GluFib) is one of the factors of thrombosis. Normal blood protein soluble, fibrinogen (fibrinopeptide A and fibrinopeptide B), is transformed into the insoluble, fibrin, which in the form of filaments adheres to the vessel wall at the site of injury, forming a grid. However, the spatial structure of this peptide has not been established till now. In this article, GluFib peptide is investigated together with dodecylphosphocholine (DPC) micelles which were used for mimicking the environment of peptide in blood vessels. The spatial structure was obtained by applying 1D and 2D 1H-1H NMR spectroscopy (TOCSY, NOESY). It was shown that the fibrinopeptide B does not have a secondary structure but we can distinguish the fragment Gly 9 – Arg 14 with a good convergence (the backbone RMSD for the Gly9 – Arg14 is 0.18 ± 0.08 Å).

  • 31.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Afonin, Sergei
    Karlsruhe Institute of Technology.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial Structures of PAP(262–270) and PAP(274–284), Two Selected Fragments of PAP(248–286), an Enhancer of HIV Infectivity2015Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 46, nr 7, s. 757-769Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Prostatic acid phosphatase (PAP) assembles into amyloid fibrils that facilitate infection by HIV. Its peptide fragments PAP(248–286) and PAP(85–120) also enhance attachment of the virus by viral adhesion to the host cell prior to receptor-specific binding via reducing the electrostatic repulsion between the membranes of the virus and the target cell. The secondary structure of monomeric PAP(248–286) in a biomembrane-mimicking environment can be separated into an N-terminal unordered region, an α-helical central domain, and an α/310-helical C-terminal section (Nanga et al., J. Am. Chem. Soc., 131:17972–17979, 2009). In this work, we used two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy techniques to study spatial structures of isolated central [PAP(262–270)] and C-terminal [PAP(274–284)] fragments of PAP(248–286) in SDS micelle solutions. NMR studies revealed the formation of complexes of both peptides with SDS micelles, with attraction to the micelle membranes occurring mainly through nonpolar and uncharged residues of the peptides. We demonstrate that, when interacting with SDS micelles, PAP(262–270) and PAP(274–284) form α-helical and 310-helical secondary structures, respectively, similar to that found previously for the 39-residue PAP(248–286).

  • 32.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Karataeva, Farida Kh.
    Alexander Butlerov Institute of Chemistry, Kazan Federal University.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of oligopeptide PAP(248-261), the N-terminal fragment of the HIV enhancer prostatic acid phosphatase peptide PAP(248-286), in aqueous and SDS micelle solutions2014Ingår i: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1070, s. 38-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Prostatic acid phosphatase (PAP) is an enzyme that facilitates infection of cells by HIV. Its peptide fragment PAP(248-286) forms amyloid fibrils known as SEVI, which enhance attachment of the virus by viral adhesion to the host cell prior to receptor-specific binding via reducing the electrostatic repulsion between the membranes of the virus and the target cell. The secondary structure of PAP(248-286) in aqueous and SDS solutions can be divided into an N-terminal disordered region, an -helical central part and an /310-helical C-terminal region (R.P.R. Nanga et al., JACS, 2009, 131, 17972). In this work, we used NMR spectroscopy to study the spatial structure of the isolated N-terminal fragment of PAP(248-286), PAP(248-261) (GIHKQKEKSRLQGG), in aqueous and SDS micelle solutions. Formation of a PAP(248-261)-SDS complex was confirmed by chemical shift alterations in the 1H NMR spectra of the peptide, as well as by the signs and values of Nuclear Overhauser Effect (NOE). In addition, the PAP(248-261) peptide does not form any specified secondary structure in either aqueous or SDS solutions.

  • 33.
    Blokhin, D.S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University, Kazan, Russia.
    Efimov, S.V.
    Institute of Physics, Kazan (Volga Region) Federal University, Kazan, Russia.
    Klochkov, A.V.
    Institute of Physics, Kazan (Volga Region) Federal University, Kazan, Russia.
    Yulmetov, A.R.
    Institute of Physics, Kazan (Volga Region) Federal University, Kazan, Russia.
    Filippov, Andrei
    Institute of Physics, Kazan (Volga Region) Federal University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik. Department of Physics, Warwick University, Coventry, UK.
    Aganov, A.G.
    Institute of Physics, Kazan (Volga Region) Federal University, Kazan, Russia.
    Klochkov, V.V.
    Institute of Physics, Kazan (Volga Region) Federal University, Kazan, Russia.
    Spatial structure of the decapeptide Val-Ile-Lys-Lys-Ser-Thr-Ala-Leu-Leu-Gly in water and in a complex with sodium dodecyl sulfate micelles2011Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 41, nr 2-4, s. 267-282Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have studied the spatial structure of the decapeptide Val-Ile-Lys-Lys-Ser-Thr-Ala-Leu-Leu-Gly in aqueous solution and in a complex with sodium dodecyl sulfate (SDS) micelles by 1H nuclear magnetic resonance (NMR) spectroscopy and two-dimensional (2-D) NMR spectroscopy (total correlation spectroscopy and nuclear Overhauser effect spectroscopy (NOESY)). The approach used to determine the decapeptide spatial structure was based on analysis of the 1H–13C residual dipolar couplings in the molecules partially aligned in lyotropic liquid crystalline media. Analysis of the interproton distances obtained from the 2-D NOESY NMR spectrum was used to reveal the spatial structure of the decapeptide in a complex with SDS micelles. Complex formation was confirmed by analysis of 1H chemical shifts in the NMR spectrum of the decapeptide and analysis of the signs and values of NOEs in a solution with SDS micelles.

  • 34.
    Butakov, Anatoly
    et al.
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Gimatdinov, Roustam
    Medical and Biological Physics, Kazan Medical University, Kazan, Russian Federation.
    Chernov, Vladimir
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk, Russian Federation.
    Peculiarities of NMR relaxation in micellar gels of Pluronic F-1272019Ingår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 40, nr 3, s. 403-407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on the 1H relaxation of transverse nuclear magnetization of triblock-copolymer Pluronic F-127 in D2O, we proposed a model of the associated pluronic structure in which the polyethylene oxide of molecules in neighboring micelles are intertwined in regions of overlapping micellar coronas, while the polypropylene oxide cores of the micelles play a role of nodes in the 3D network. 

  • 35.
    Dvoyashkin, Dvoyashkin
    et al.
    aculty of Oil and Gas, Almetyevsk State Oil Institute.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Diffusivity of crude oils contained in macroporous medium: 1H NMR study2018Ingår i: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 2, s. 222-224Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Diffusivity of crude oils confined in pores of sand decreased with raising the fraction of oil at ordinary temperatures. This behaviour is suggested to be caused by adsorption of the high-molecular fractions of oils at the solid–liquid interface.

  • 36.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Self-Diffusion and Microstructure of Some Ionic Liquids in Bulk and in Confinement2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    An ionic liquid (IL) is a salt, which usually is in the liquid state at normal temperature and pressure. The properties of ILs can be adjusted for various processes and applications by choosing different combinations of ions. Similar to other salts, ILs contain only ions with positive (cations) and negative (anions) charges in equal proportions. However, to prevent solidification, ions in ionic liquids usually contain bulky organic chemical groups, which, apart from electrostatic interactions, promote other types of interactions between ions, such as: (i) van-der-Waals interactions; (ii) hydrogen bonding; (iii) - stacking, etc., depending on the particular chemical structure of the ions. All these interactions, in combination, may lead to formation of specific microstructures in ILs, which may vary with temperature caused by changing thermal rotational and translational energies of the ions. Ions in these microstructures may have preferential orientations relative to each other, maintain anisotropic properties similar to those in liquid crystals or, in some specific cases, may even separate into microscopically organised liquid phases. Therefore, the dynamics of ILs may also be dependent on their microstructure. In many practical applications ionic liquids are placed on surfaces or in confinements. Solid surfaces introduce extra forces, which may be specific to the charge of the ions or/and to functional groups in the ILs. The geometry and interactions of ions in confinements or/and pores of materials may also disrupt specific bulk microstructures of ILs. Both confinement effects and interactions of ions with surfaces are manifested in the translational dynamics of the ions. One of the most direct and informative methods to study translational dynamics of ILs is pulse-field-gradient nuclear magnetic resonance (PFG-NMR).In this thesis the results of PFG-NMR studies on a few classes of ILs are reported: (i) the historically “standard” (since Walden’s discovery in 1914) ionic liquid, the ethylammonium nitrate (EAN) and (ii) halogen-free orthoborate-based phosphonium, imidazolium and pyrrolidinium ILs with varied structure and lengths of alkyl chains in cations, and varied structures of orthoborate anions. These ILs were studied in bulk at different temperatures, and also in confinements, such as between parallel glass and Teflon plates and in mesoporous Vycor glass. It was found that diffusion coefficients of cations and anions in EAN, phosphonium and pyrrolidinium orthoborate ILs in bulk are different, but according to the standard Stocks-Einstein model, they correspond to diffusion of ions in homogeneous liquids. A change in the chemical structure of one of the ions results in a change in both the diffusion coefficient of the oppositely charged ion and the activation energy of diffusion for both ions in an IL. Similar effects were observed from the chemical shifts and diffusion coefficients measured by NMR for imidazolium orthoborate ILs dissolved in polyethylene glycol solutions, in which imidazolium cations strongly interact with PEG molecules, further affecting the diffusion of orthoborate anions via electrostatic interactions. A liquid-liquid phase separation was suggested for a few phosphonium and pyrrolidinium bis(mandelato)borate ILs, in which a divergence of diffusion coefficients and activation energies of diffusion for cations and anions was detected at temperatures below ca 50 °C. In addition, a free-volume theory was invoked to explain the dependences of density of ILs on the alkyl chain length in cations.It was also found that for a phosphonium bis(salicylato)borate IL confined in 4 nm mesoporous Vycor glass the diffusion coefficients of ions increase by a factor of 35! This phenomenon was explained by the dynamic heterogeneity of this IL in micropores and empty voids of the Vycor glass. For EAN IL in confinements between glass and Teflon plates, the diffusion of ethylammonium cations and nitrate anions is significantly anisotropic, i.e. slower in the direction of the normal to the plates and faster along the plates compared to diffusion of the ions in bulk. A plausible explanation of this PFG NMR data is that EAN forms layers near polar and non-polar solid surfaces. A similar phenomenon, to a lesser extent, was also observed for phosphonium cations of bis(mandelato)borate, bis(salicylato)borate and bis(oxalato)borate confined between glass plates. The results of these studies may have implications in modeling tribological performance, i.e., friction and wear reduction for contact pairs of different materials lubricated by various classes of ionic liquids.

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  • 37.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Synthesis and aggregation studies on amyloid oligomers of Alzheimer's Ab peptides2010Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 38.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, 420012 Kazan, Russia.
    Alexandrov, Artem S.
    Kazan Federal University, 420008 Kazan, Russia.
    Gimatdinov, Rustam
    Kazan State Medical University, 420012 Kazan, Russia.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Unusual ion transport behaviour of ethylammonium nitrate mixed with lithium nitrate2021Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 340, artikel-id 116841Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The diffusivity of ions and ionic conductivity of ethylammonium nitrate (EAN) mixed with lithium nitrate (LiNO3) has been carried out as a function of Li-salt concentration and temperature. An unusual behavior of ion diffusivities and ionic conductivities of the mixtures are observed over a range of Li-salt concentration and temperature. The diffusivities of EA+ and Li+, as measured by pulsed-field gradient (PFG) nuclear magnetic resonance (NMR) diffusometry, are found to be comparable in the lower temperature range. An overall decrease in the ion diffusivity is observed with an increase in the concentration of LiNO3. A lower degree of dissociation of ionic complexes in the presence lower concentration of the Li-salt (less than 6 mol. %) resulted in lower ionic conductivity. In the higher concentration range of Li-salt the Li+ diffusivity is monotonously decreased with an increase in the concentration. In the lower concentration range, the Li+ diffusivity exceeded the diffusivity of EA+ cation demonstrating the release of Li+ from the associates. Being enclosed between glass plates, the diffusivities of EA+ and Li+ showed peculiarities similar to the earlier observed results for neat nitrate ILs: accelerated diffusivity of cations and reversible alteration of diffusivities under the influence of strong static magnetic field.

  • 39.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Influence of Alzheimer´s beta-amyloid peptide on the lateral diffusion of lipids in raft-forming bilayers2013Ingår i: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 23, nr 6, s. 316-318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the first time effect of added Alzheimer´s Abeta(1-40) peptide of wild type on lateral diffusion of lipids in macroscopically oriented bilayers of “raft” compositions (mixture of dioleoylphosphatidylcholine (DOPC), sphingomielin (SM) and cholesterol (CHOL)) was studied by NMR-diffusion technique. In homogeneous bilayers diffusion coefficients decrease, while in liquid ordered and in liquid disordered phases they change differently at varied concentrations of CHOL that was explained by decreased maximum solubility of CHOL in phospholipids in the presence of Abeta(1-40) peptide.

  • 40.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, CV4 7AL Coventry, UK.
    Gimatdinov, Rustam
    Kazan State Medical University, Kazan, Russia.
    Gnezdilovd, Oleg I.
    Kazan Federal University, Kazan, Russia. Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.
    Self-diffusion in ionic liquids with nitrate anion: Effects of confinement between glass plates and static magnetic field2020Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 312, artikel-id 113404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alkylammonium nitrate protic ionic liquids (ILs), when placed between flat polar borosilicate glass plates, have demonstrated enhanced diffusivity and the gradual decrease of diffusivity after exposure to an external static magnetic field (Filippov et al., 2018). This phenomenon has been explained by phase transformations taking place in the ILs. In this study, we observed similar processes occurring in systems prepared with ethylammonium nitrate confined between quartz plates. A higher content of silicon oxide in the plates does not significantly alter the phenomenon previously found in the system prepared with borosilicate glass plates. For the first time, we have observed similar effects of confinement and magnetic field on the aprotic IL, 1‑ethyl‑3‑methylimidazolium nitrate. Substitution of the ethylammonium cation with a 1‑ethyl‑3‑methylimidazolium cation slows down the kinetics and increases magnitude of the processes occurring in the IL exposed to a magnetic field. We suggested that the main factor determining these effects is the presence and modification of the hydrogen-bonding network in the studied protic and aprotic ILs. The process of inverse phase transformation for the confined ethylammonium nitrate after removing the sample from the magnetic field was observed and analysed.

  • 41.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russia .
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry, United Kingdom .
    Magnetic field effects dynamics of ethylammonium nitrate ionic liquid confined between glass plates2018Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, nr 9, s. 6316-6320Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Self-diffusion and NMR relaxation of the ethylammonium (EA) cation were studied in the protic ionic liquid, ethylammonium nitrate (EAN), confined between polar glass plates separated by a few μm distance and exposed to an external magnetic field of 9.4 T. The diffusion coefficient of EA (D) and the transverse NMR relaxation rate (1/T2) of –NH3 protons were increased immediately after placing the sample in the magnetic field by factors of ∼2 and ∼22, respectively, in comparison with those of bulk EAN. Further exposure of the sample to the magnetic field led to gradual changes in D, T1 and T2 towards their bulk values with a time constant of ∼70 min. Complete “recovery” of the sample to the “accelerated” D and “shortened” T2 values occurred at longer than 24 hours after the removal of the EAN sample from the magnet. Because the observed characteristic times of the change far exceed the times of molecular processes in EAN, we suggested that this phenomenon is related to reversible phase transformations occurring in confined EAN.

  • 42.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    State of anion in ethylammonium nitrate enclosed between micrometer-spaced glass plates as studied by 17O and 15N NMR2023Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 25, nr 20, s. 14538-14545Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Some aprotic and protic ionic liquids (ILs) containing nitrate anion demonstrate unusual dynamic behavior of cations when these ILs are enclosed in micrometer-spaced layers between glass plates. We applied 17O and 15N NMR spectroscopy to discover the state and transformations of 17O and 15N isotopically enriched nitrate anion of ethylammonium nitrate (EAN) enclosed between glass plates. 15N NMR spectra demonstrated preferential orientation of the principal axes of the nitrate anions perpendicular to the normal of the glass surface. Therefore, isotropic ionic liquid EAN, when placed within a micrometer-spaced enclosure, forms an ordered phase, which is similar to a liquid crystal. The peculiarity of this phase is that the cations do not have a predominant orientation. Other features of this phase that are typical for liquid crystal phases are the changed local and translational dynamics in comparison with the isotropic state and slow transformation occurring under the action of an external magnetic field.

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  • 43.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Arkhipov, Victor P.
    Department of Physics, Kazan National Research Technological University, 420015 Kazan, Russia.
    Gnezdilov, Oleg I.
    Institute of Physics, Kazan Federal University, 420008 Kazan, Russia.
    Diffusivity of ethylammonium nitrate protic ionic liquid confined in porous glasses2022Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 356, artikel-id 118998Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We studied the diffusion of ionic liquid ethylammonium nitrate confined within pores of two types of porous glass, Vycor and Varapor, with average pore sizes of 4 nm and 9.8 nm, respectively, by 1H NMR in the temperature range of 295–325 K. The diffusional behavior of the ionic liquid corresponds to long-term diffusion in a system of interconnected pores. It was shown that the diffusivity of EAN confined in Varapor is controlled by the porous system’s tortuosity and does need to take into consideration the interaction with the surface of the discrete pore walls. In the case of Vycor, the long-term diffusivity is a factor 1.5 lower than that expected in the absence of interaction with the pore walls. Two possible mechanisms that may explain this discrepancy are the EAN-surface interaction and retardation of EAN diffusion compared to n-decane in smaller pores present in Vycor porous glass due to pore size distribution. Confinement of EAN in nanoporous glass does not leads to the EAN phase transformation observed earlier for alkylammonium nitrates enclosed in a micrometer-sized layer. Prolonged exposure of EAN to a strong static magnetic field does not leads to changes in the NMR and diffusivity of EAN over time.

  • 44.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry, UK.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rapid carbene formation increasing ion diffusivity in an imidazolium acetate ionic liquid confined between polar glass plates2019Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 21, nr 40, s. 22531-22538Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1-Ethyl-3-methyl-imidazolium acetate ([EMIM][OAc]) is one of the most widely used ionic liquids for various applications. This study is focussed on the chemical stability of [EMIM][OAc] on the surfaces of polar glass plates. 1H and 13C NMR spectroscopy and NMR diffusometry of [EMIM][OAc] IL confined between glass plates with a specific surface area 105–106 m−1 are thoroughly investigated. A rapid and spontaneous reaction took place on the surfaces of glass plates leading to the formation of neutral chemical moieties as evident by the appearance of new signals in the 1H NMR spectra. These new products are assigned as N-heterocyclic carbene (NHC) and acetic acid. These neutral chemical moieties have significantly increased the ion diffusivity by dissociation of the cation and the anion in [EMIM][OAc] IL. The yield and rate of formation of NHC and acetic acid are found to increase with the increasing surface area of polar glass plates and the time of contact between the IL and glass surfaces. Based on NMR spectroscopy, a dissociative reaction mechanism is proposed for the formation of free NHC in the neat [EMIM][OAc] IL.

  • 45.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry, UK.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Reactivity of CO2 with aqueous choline-based ionic liquids probed by solid-state NMR spectroscopy2019Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 286, artikel-id 110918Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    CO2 absorption in a series of choline-based ionic liquids is investigated using solid-state 13C and 15N MAS NMR spectroscopy. Natural abundance and 13C enriched CO2 gas was purged through 50 wt% aqueous solutions of alkyldimethyl(2-hydroxyethyl)ammonium threonine, [N1,1,n,2OH][Threo], (alkyl = butyl, pentyl and hexyl) and pentyldimethyl(2-hydroxyethyl)ammonium taurine [N1,1,5,2OH][Tau]. The process of CO2 absorption results in precipitation of a solid sediment, which stays in equilibrium with the liquid phase. Upon degassing of the sample, the sediment is dissolved back into the IL-aqueous phase. Solid state 13C and 15N MAS NMR data suggest that the solid sediment is composed of neutral threonine (or taurine) in the zwitterionic forms and the liquid phase contained the products of reactions between the ionic liquids and CO2 molecules. A plausible mechanism for formation of the solid sediments and the reaction products in liquid phases is suggested.

  • 46.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry, U.K.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Understanding the Interaction of Boric Acid and CO2 with Ionic Liquids in Aqueous Medium by Multinuclear NMR Spectroscopy2020Ingår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 8, nr 1, s. 552-560Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Boric acid is known to enhance the kinetics of CO2 absorption by some active aqueous solutions. However, the mechanism of interaction of boric acid with CO2 in the presence of active molecules is not yet fully understood. In this work, the interaction and dynamics of ions in aqueous solutions of functionalized choline-based ionic liquids [N1,1,5,2OH][Threo] and [N1,1,5,2OH][Tau] in the presence of boric acid and CO2 was thoroughly investigated using a multinuclear NMR approach: 13C and 11B NMR spectroscopy, 11B NMR transverse relaxation, and 1H and 11B NMR diffusometry. 13C and 11B NMR spectroscopy revealed the formation of borate-based complexes as a result of a reaction between boric acid and the anions of the ILs at ionic liquid/boric acid molar ratios larger than ca. 0.15. The formation of these complexes and their dynamics were further investigated using 11B relaxation and 1H and 11B pulse-field-gradient (PFG) NMR. Plausible reaction mechanisms of boric acid with the anions of the ILs, formation of the borate complexes, and dissociation of these complexes facilitated by CO2 molecules are suggested.

  • 47.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Artamonova, Marina
    Kazan (Volga Region) Federal University, Kazan.
    Rudakova, Maya
    Kazan (Volga Region) Federal University, Kazan.
    Gimatdinov, Roustam
    Kazan (Volga Region) Federal University, Kazan.
    Skirda, Vladimir
    Kazan (Volga Region) Federal University, Kazan.
    Self-diffusion in a hyaluronic acid–albumin–water system as studied by NMR2012Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 50, nr 2, s. 114-119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the presence of even a small amount of hyaluronic acid, the self-diffusion coefficient of albumin decreases. Three hypotheses were proposed and analyzed. The most likely one is that BSA and HA molecules form complex. The state of the BSA molecules in the BSA-HA-D2O system corresponds to a ‘fast exchange’ condition from the NMR point of view: BSA molecules reside in the ‘free’ and ‘bound’ states for much shorter time than the diffusion time of the PFG NMR experiment. Hyaluronic acid (HA) is an anionic biopolymer that is present in many tissues and can be involved in cancerous neoformations. HA can form complexes with proteins (particularly, serum albumin) in the body. However, HA structures and processes involving HA have not been extensively studied by NMR because the molecule's rigid structure makes these studies problematic. In the current work, self-diffusion of HA and bovine serum albumin (BSA), and water in solutions was measured by 1H pulsed field gradient NMR (PFG NMR) with a focus on the HA-BSA-D2O systems at various concentrations of BSA and HA. It was shown that in the presence of even a small amount of HA, the self-diffusion coefficient (SDC) of BSA decreases. To explain this fact, three hypotheses were proposed and analyzed. The first one was based on the effect of slowing down of water mobility in the presence of HA. The second hypothesis suggested an effect of mechanical collisions of BSA with HA molecules. The third hypothesized that BSA and HA molecules form a complex where BSA molecules reduced in mobility. It was shown that the third mechanism is the most likely. The state of the BSA molecules in the BSA-HA-D2O system corresponds to a ‘fast exchange’ condition from the NMR point of view: BSA molecules reside in the ‘free’ and ‘bound’ (with HA) states for much shorter time than the diffusion time of the PFG NMR experiment, 7 ms. The fractions of ‘bound’ BSA molecules in the BSA-HA complex were estimated.

  • 48.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Azancheev, Nail
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Gibaydullin, Amal
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Bhattacharyya, Shubhankar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Dynamic Properties of Imidazolium Orthoborate Ionic Liquids Mixed with Polyethylene Glycol Studied by NMR Diffusometry and Impedance Spectroscopy2018Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 56, nr 2, s. 113-119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We used 1H pulsed field gradient (PFG) NMR to study the self-diffusion of polyethylene glycol (PEG) with average molecular mass of 200 and ions in mixtures of PEG with imidazolium bis(mandelato)borate (BMB) and imidazolium bis(oxalato)borate (BOB) ionic liquids (ILs). The ionic liquid was mixed with PEG in the concentration range of 0–100 wt%. Within the temperature range of 295 to 353 K, the diffusion coefficient of BMB is slower than that of the imidazolium cation. The diffusion coefficients of PEG, as well as the imidazolium cation and BMB anions, differ under all experimental conditions tested. This demonstrates that the IL in the mixture is present in at least a partially dissociated state. Generally, increasing the concentration of PEG leads to an increase in the diffusion coefficients of PEG and both the ions, and decreases their activation energy for diffusion. NMR chemical shift alteration analysis showed that the presence of PEG changes the chemical shifts of both ions but in different directions. Impedance spectroscopy was used to measure the ionic conductivity of the ionic liquids mixed with PEG.

  • 49.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Azancheev, Nail
    Kazan (Volga Region) Federal University, Kazan, Russia.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Glavatskikh, Sergei
    System and Component Design, KTH Royal Institute of Technology, SE-10 044, Stockholm, Sweden; Department of Mechanical Construction and Production, Ghent University, B-9000, Ghent, Belgium.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Self-Diffusion of Phosphonium Bis(Salicylato)Borate Ionic Liquid in Pores of Vycor Porous Glass2016Ingår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 230, s. 128-134Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1H NMR pulsed field gradient was used to study self-diffusion of a phosphonium bis(salicylato)borate ionic liquid ([P6,6,6,14][BScB]) in the pores of Vycor porous glass at 296 K. Confinement in pores increases diffusion coefficients of the ions by a factor of 35. However, some [P6,6,6,14][BScB] ions demonstrated apparent diffusion coefficients much lower than their mean values, which may be due to partially restricted diffusion of the ions. We suggest that this fraction corresponds to areas where ions are confined by pore ‘necks’ (micropores) and empty voids. Heating of the ionic liquid / Vycor system at 330 K led to a change in the diffusivity of the ions, because of their redistribution in the pores. The size of the bounded regions is on the order of 1 µm, as estimated from the dependence of the ion diffusivity on the diffusion time.

  • 50.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Azancheev, Nail
    Kazan (Volga Region) Federal University, Kazan.
    Taher, Mamoun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rabét, Pauline
    Department of Organic Chemistry, School of Chemistry, Manchester University.
    Glavatskih, Sergei
    System and Component Design, KTH, Royal Institute of Technology , Machine Design, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden, Department of Physics, Warwick University, Coventry, Department of Mechanical Construction and Production, Ghent University.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Self-diffusion and interactions in mixtures of imidazolium bis(mandelato)borate ionic liquids with polyethylene glycol: 1H NMR study2015Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 53, nr 7, s. 493-497Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We used 1H nuclear magnetic resonance pulsed-field gradient to study the self-diffusion of polyethylene glycol (PEG) and ions in a mixture of PEG and imidazolium bis(mandelato)borate ionic liquids (ILs) at IL concentrations from 0 to 10 wt% and temperatures from 295 to 370 K. PEG behaves as a solvent for these ILs, allowing observation of separate lines in 1H NMR spectra assigned to the cation and anion as well as to PEG. The diffusion coefficients of PEG, as well as the imidazolium cation and bis(mandelato)borate (BMB) anion, differ under all experimental conditions tested. This demonstrates that the IL in the mixture is present in at least a partially dissociated state, while the lifetimes of the associated states of the ions and ions with PEG are less than ~30 ms. Generally, increasing the concentration of the IL leads to a decrease in the diffusion coefficients of PEG and both ions. The diffusion coefficient of the anion is less than that of the cation; the molecular mass dependence of diffusion of ions can be described by the Stokes–Einstein model. NMR chemical shift alteration analysis showed that the presence of PEG changes mainly the chemical shifts of protons belonging to imidazole ring of the cation, while chemical shifts of protons of anions and PEG remain unchanged. This demonstrated that the imidazolium cation interacts mainly with PEG, which most probably occurs through the oxygen of PEG and the imidazole ring. The BMB anion does not strongly interact with PEG, but it may be indirectly affected by PEG through interaction with the cation, which directly interacts with PEG

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