Change search
Refine search result
12345 1 - 50 of 210
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Trublet, Mylène
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rusanova-Naydenova, Daniela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg N
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, CV47AL, UK.
    Correction: Revisiting syntheses of Ti(IV)/H2PO4–HPO4functional ion-exchangers, properties and features2018In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 42, no 2, p. 1521-Article in journal (Refereed)
  • 2.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Azancheev, Nail
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Gibaydullin, Amal
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Bhattacharyya, Shubhankar
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Dynamic Properties of Imidazolium Orthoborate Ionic Liquids Mixed with Polyethylene Glycol Studied by NMR Diffusometry and Impedance Spectroscopy2018In: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 56, no 2, p. 113-119Article in journal (Refereed)
    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.

  • 3.
    Pilkington, Georgia A.
    et al.
    Surface and Corrosion Science, Department of Chemistry, KTH Royal Institute of Technology.
    Harris, Kathryn
    System and Component Design, Department of Machine Design, KTH Royal Institute of Technology.
    Bergendal, Erik
    Surface and Corrosion Science, Department of Chemistry, KTH Royal Institute of Technology.
    Reddy, Akepati Bhaskar
    System and Component Design, Department of Machine Design, KTH Royal Institute of Technology.
    Pålsson, Gunnar K.
    Department of Physics and Astronomy, Division of Materials Physics, Uppsala University.
    Vorobiev, Alexei
    Department of Physics and Astronomy, Division of Materials Physics, Uppsala University.
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskih, Sergei
    System and Component Design, Department of Machine Design, KTH Royal Institute of Technology.
    Rutland, Mark W.
    Surface and Corrosion Science, Department of Chemistry, KTH Royal Institute of Technology.
    Electro-responsivity of ionic liquid boundary layers in a polar solvent revealed by neutron reflectance2018In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 148, article id 193806Article in journal (Refereed)
    Abstract [en]

    Using neutron reflectivity, the electro-responsive structuring of the non-halogenated ionic liquid (IL) trihexyl(tetradecyl)phosphonium-bis(mandelato)borate, [P6,6,6,14][BMB], has been studied at a gold electrode surface in a polar solvent. For a 20% w/w IL mixture, contrast matched to the gold surface, distinct Kiessig fringes were observed for all potentials studied, indicative of a boundary layer of different composition to that of the bulk IL-solvent mixture. With applied potential, the amplitudes of the fringes from the gold-boundary layer interface varied systematically. These changes are attributable to the differing ratios of cations and anions in the boundary layer, leading to a greater or diminished contrast with the gold electrode, depending on the individual ion scattering length densities. Such electro-responsive changes were also evident in the reflectivities measured for the pure IL and a less concentrated (5% w/w) IL-solvent mixture at the same applied potentials, but gave rise to less pronounced changes. These measurements, therefore, demonstrate the enhanced sensitivity achieved by contrast matching the bulk solution and that the structure of the IL boundary layers formed in mixtures is strongly influenced by the bulk concentration. Together these results represent an important step in characterising IL boundary layers in IL-solvent mixtures and provide clear evidence of electro-responsive structuring of IL ions in their solutions with applied potential.

  • 4.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Institute of Physics, Kazan Federal University, Kazan, Russia .
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, Coventry, United Kingdom .
    Magnetic field effects dynamics of ethylammonium nitrate ionic liquid confined between glass plates2018In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 9, p. 6316-6320Article in journal (Refereed)
    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.

  • 5.
    Trublet, Mylène
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rusanova-Naydenova, Daniela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg N
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, CV47AL, UK.
    Revisiting syntheses of Ti(IV)/H2PO4–HPO4functional ion-exchangers, properties and features2018In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 42, no 2, p. 838-845Article in journal (Refereed)
    Abstract [en]

    Amorphous titanium phosphate ion-exchangers are often of a “mixed type”, i.e., they contain a mixture of –HPO4 and –H2PO4 active groups. Their synthesis requires careful handling to obtain the same proportion of active units and sorption characteristics. This article focuses on the influence of titanium sources and post-synthetic treatments on the uniform synthesis of amorphous TiP1 (TiO(OH)(H2PO4)·H2O). It also describes a mild and straightforward method for obtaining crystalline α-TiP (Ti(HPO4)2·H2O). Amorphous TiP1 was successfully synthesized using five sources of titanium providing that the content of titanium and H2SO4 in the primary solution was 60–110 g L−1 and 400 ± 50 g L−1, respectively. Observations revealed that organic and inorganic acids could also be comparably used in post-synthetic treatments to protonate the phosphate groups into –H2PO4 units. The Na+ uptake (up to 7.2 meq g−1) and ion-exchange capacities towards divalent ions (up to 3.8 meq g−1) of all the TiP1-type sorbents studied are among the highest reported for TiP systems. Despite differences in the surface characteristics, the TiP1 materials synthesized in this study displayed comparable sorption properties, supporting the fact that chemisorption is the governing factor behind the sorption processes. Crystalline α-TiP is obtained under similar mild synthesis conditions when the P2O5 : TiO2 molar ratio is greater than 1 : 1, regardless of the titanium source. The possibility of using various types of TiOSO4 as a titanium source for TiP1 and α-TiP syntheses is emphasized and all reported data are re-considered from a synthetic perspective.

  • 6.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Gnezdilov, Oleg I.
    Institute of Physics, Kazan Federal University.
    Hjalmarsson, Nicklas
    Surface and Corrosion Science, KTH Royal Institute of Technology.
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskih, Sergei
    System and Component Design, Department of Machine Design, KTH Royal Institute of Technology.
    Furo, Istvan
    Applied Physical Chemistry, KTH Royal Institute of Technology.
    Rutland, Mark W.
    Surface and Corrosion Science, KTH Royal Institute of Technology.
    Acceleration of diffusion in ethylammonium nitrate ionic liquid confined between parallel glass plates2017In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 38, p. 25853-25858Article in journal (Refereed)
    Abstract [en]

    Diffusion of EAN confined between polar glass plates separated by a few micrometers is higher by a factor of ca. 2 as compared to bulk values. Formation of a new phase, different to the bulk, was suggested.

  • 7.
    Korneeva, E.V.
    et al.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Larsson, Anna-Carin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences .
    Novikova, E.V.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Smolentsev, A.I.
    Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Crystalline nickel(II) di-i-amyl dithiophosphate, [Ni{S2P(O-i-C5H11)2}2]: Preparation, structure, heteronuclear (13C, 31P) CP/MAS NMR spectra, and thermal behavior2017In: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 43, no 4, p. 223-231Article in journal (Refereed)
    Abstract [en]

    The crystalline nickel(II) di-i-amyl) dithiophosphate (Dtph), [Ni{S2P(O-i-C5H11)2}2] (I) was isolated on a preparative scale and characterized by 13C, 31P MAS NMR, and X-ray diffraction (CIF file CCDC no. 1469369). The χ2-statistic diagrams were constructed from full 31P CP/MAS NMR spectra for calculating the 31P chemical shift anisotropy: δaniso = δzz–δiso and the asymmetry parameter η = (δyy–δxx)/(δzz–δiso). The key structural unit of I is the centrosymmetric [Ni{S2P(O-i-C5H11)2}2] molecule in which the nickel atom coordinates two Dtph ligands in the isobidentate fashion. In molecule I, each carbon, oxygen, and sulfur atom is statistically disordered over two sites with equal occupancies. However, the disorder does not affect nickel and phosphorus. These results were interpreted as the presence in I of two [Ni{S2P(O-i-C5H11)2}2] molecules rotated through 21.0(1)° (the angle between the [NiS4] chromophore planes) relative to each other around the bisecting P–Ni–P axis passing through both four-membered [NiS2P] rings. The two molecules occupy crystal lattice sites with equal probabilities. The thermal behavior of I was studied by simultaneous thermal analysis under argon. The course of the thermal destruction of the complex was established, nickel pyrophosphate (Ni2P2O7) was identified as the final product of thermal transformations.

  • 8.
    Shimpi, Manishkumar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Velaga, Sitaram
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Pharmaceutical Crystal Engineering Using Ionic Liquid Anion–Solute Interactions2017In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 17, no 4, p. 1729-1734Article in journal (Refereed)
    Abstract [en]

    The main purpose of this work was to investigate the potential of ionic liquids (ILs) in crystal engineering. We have employed ILs with different combinations of cations and anions to study their role in directing crystal structure formation of a nicotinamide (NIC) and oxalic acid (OXA) system. A new crystal form of NIC–OXA salt (2:1) was identified and characterized using standard solid state tools such as powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and Raman and infrared spectroscopy. The crystal structure of the 2:1 salt was elucidated using single-crystal X-ray diffraction. The NIC–OXA 2:1 salt form revealed a two-dimensional layered structure, while the known 1:1 salt had a perpendicular “tape-like” structure. The 2:1 salt form could only be crystallized from the ILs possessing hydrogen bond acceptor functionality. We demonstrated that specific ILs could be selected as solvents for altering the solid-state structure of organic and inorganic materials.

  • 9.
    Geng, Shiyu
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Liu, Peng
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Plasticizing and crosslinking effects of borate additives on the structure and properties of poly(vinyl acetate)2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 13, p. 7483-7491Article in journal (Refereed)
    Abstract [en]

    As an environmentally friendly, low-cost and widely used polymer, poly(vinyl acetate) (PVAc) is worth modifying to achieve better properties. Here, we report on the influence of borate additives on the structure and properties of partially hydrolysed PVAc. In addition to the general crosslinking function of borate additives, an extraordinary plasticizing effect was found. By controlling the pH from 4 to 11 during sample preparation, the plasticizing and crosslinking effects can be shifted. In alkaline conditions, the degree of crosslinking in the PVAc/borate sample is increased; however, this increase declines gradually with an increase in the borate additive content, which impacts the morphology of the PVAc latex particles, as well as the mechanical and thermal properties of the PVAc/borate films. In contrast, in acidic conditions, the PVAc/borate films are plasticized by borate additives; thus, their ultimate mechanical strength, elastic moduli and thermal stabilities decrease, while the water diffusivities increase.

  • 10.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Polymorphism of Alzheimer´s A-beta Amyloid Fibrils2017In: Modern Magnetic Resonance / [ed] Graham A. Webb, Springer International Publishing , 2017, p. 1-15Chapter in book (Other academic)
    Abstract [en]

    An overview of the strategy and experimental solid-state NMR, STEM, and AFM methods useful for obtaining structural constraints on Alzheimer’s amyloid-β peptide fibrils is presented. Polymorphism of amyloid fibrils and the relevance to neurotoxicity is discussed.

  • 11.
    Trublet, Mylene
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Maslova, Marina V.
    Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Science Center, Russian Academy of Sciences.
    Rusanova-Naydenova, Daniela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sorption performances of TiO(OH)(H2PO4)·H2O in synthetic and mine waters2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 4, p. 1989-2001Article in journal (Refereed)
    Abstract [en]

    ¨The sorption properties toward Cu2+, Zn2+, Ni2+, Mn2+ and Co2+ ions, in synthetic and industrial waters with pH of 3.9–7.2, and the chemical stability of a titanium phosphate ion-exchanger synthesized at mild conditions and containing solely –H2PO4 groups, TiO(OH)(H2PO4)·H2O (TiP1) are investigated. TiP1 displays the highest Na+ uptake (6.3 meq. g−1) among TiP ion-exchangers and a maximum sorption capacity of ca. 1.55 mmol g−1 (i.e. 3.1 meq. g−1) for the studied ions, which is higher than the ones reported for exchangers composed predominantly of –HPO4 groups. The sorption isotherms were best described by the Temkin model while the Langmuir and the Freundlich models appear to be insufficient in describing all data. TiP1 shows fast kinetics with an equilibrium reached within 10–20 minutes and diffusion processes play a role in the initial period of sorption that is overpowered by chemisorption reactions in the overall rate controlling step. The selectivity order of the metal ions on TiP1 is determined as: Cu2+ > Zn2+ ≫ Mn2+ > Co2+, Ni2+, following the order of stability of MOH+ complexes and the corresponding activation parameters for a water molecule exchange in [M(H2O)6]2+ ions. The surface sorption data are in good correlation with the EDS data for these systems, supporting the idea of chemical sorption with no metal hydroxide precipitation. Additional sorption studies show that the quality of industrial waters after sorption reaches the EU recommendation for drinking water. The faster kinetics and the higher exchange capacity reveal that the presence of –H2PO4 groups strongly enhances the sorption properties of titanium phosphate sorbents.

  • 12.
    Gowda, Vasantha
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. NMR Research Unit, University of Oulu.
    Sarma, Bipul
    Department of Chemical Sciences, Tezpur University.
    Laitinen, Risto S.
    Laboratory of Inorganic Chemistry, University of Oulu.
    Larsson, Anna-Carin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences .
    Iuga, Dinu
    Department of Physics, Warwick University.
    Lantto, Perttu
    NMR Research Unit, University of Oulu.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University.
    Structural insights into the polymorphism of bismuth(III) di-n-butyldithiocarbamate by X-ray diffraction, solid-state (13C/15N) CP-MAS NMR and DFT calculations2017In: Polyhedron, ISSN 0277-5387, E-ISSN 1873-3719, Vol. 129, p. 123-132Article in journal (Refereed)
    Abstract [en]

    Two crystalline polymorphs of a binuclear tris(di-n-butyldithiocarbamato)bismuth(III) complex, I and II, with an empirical formula of [Bi{S2CN(n-C4H9)2}3] were synthesised and characterised by X-ray diffraction (XRD), solid-state NMR and density functional theory (DFT) calculations. At the supramolecular level, these mononuclear molecular units interact in pairs via secondary Bi⋯S bonds, yielding binuclear formations of [Bi2{S2CN(n-C4H9)2}6]. The polymorph I () contains two isomeric non-centrosymmetric binuclear molecules of [Bi2{S2CN(n-C4H9)2}6], which are related to each other as conformers, therefore having four structurally inequivalent bismuth atoms and twelve inequivalent dithiocarbamate ligands. In contrast, the structurally simpler polymorph II (P21/n) exists as a single molecular form of the corresponding centrosymmetric binuclear formation, comprising two structurally equivalent bismuth atoms and three structurally different dithiocarbamate groups. The polymorphs I and II were found to be interconvertible by altering the solvent system during the recrystallisation process. Sun et al. (2012) has reported a crystalline form of the title compound which resembles, but is not identical with, polymorph II. Experimental solid-state 13C and 15N cross-polarisation (CP) magic-angle-spinning (MAS) NMR spectra of both polymorphs I and II were in accord with the direct structural data on these complexes. Assignments of the resonance lines in the solid-state 13C and 15N NMR spectra were assisted by chemical shift calculations of the crystals using periodic DFT.

  • 13.
    Bredyuk, O.A.
    et al.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences.
    Loseva, Olga V.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences .
    Gowda, Vasantha
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. University of Oulu.
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Warwick University, Coventry.
    Three-Dimensional Polymeric Thallium(I) Morpholinedithiocarbamate [Tl2{S2CN(CH2)4O}2]n and Its Capability of Binding Gold(III) from Solutions: Chemisorption Synthesis of a Heteronuclear Gold(III)–Thallium(III) Complex of the Ionic Type, ([Au{S2CN(CH2)4O}2][TlCl4])n, the Role of Secondary Interactions Tl…O, Tl…S, and Au…S in the Supramolecular Self-Organization, 13C MAS NMR, and Thermal Behavior2017In: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 43, no 10, p. 638-651Article in journal (Refereed)
    Abstract [en]

    Crystalline polymeric thallium(I) morpholinedithiocarbamate [Tl2{S2CN(CH2)4O}2]n (I) and the heteronuclear ion–polymeric gold(III)–thalium(III) complex ([Au{S2CN(CH2)4O}2][TlCl4])n (II) are preparatively isolated and characterized by X-ray diffraction analysis and 13C MAS NMR spectroscopy. According to the X-ray diffraction data, the main structural units of compounds I and II (CIF files CCDC 1548079 and 1548080) are presented by the binuclear centrosymmetric molecule [Tl2{S2CN(CH2)4O}2], noncentrosymmetric complex cation [Au{S2CN(CH2)4O{2]+, and isomeric complex anions [TlCl4]. The formation of the three-dimensional polymeric structure (coordination number of Tl is 7), which is not characteristic of thallium(I) dithiocarbamates, is a consequence of the participation of the secondary Tl…O and Tl…S bonds of two types in the supramolecular self-organization of compound I. Nonequivalent secondary interactions of the first type join the binuclear molecules [Tl2{S2CN(CH2)4O}2] into polymer layers, which, in turn, form the three-dimensional polymeric framework due to the secondary bonds Tl…S. The revealed ability of freshly precipitated compound I to the chemisorption of gold(III) from solutions (2 M HCl) makes it possible to obtain heteronuclear supramolecular complex II as an individual form of binding. In the structure of the latter, the pairs of stronger secondary Au…S bonds join the gold(III) cations into dimers [Au2{S2CN(CH2)4O}4]2+ of the angular structure, the structural ordering of which is achieved in the cationcationic polymeric chain ([Au2{S2CN(CH2)4O}4]2+)n of the helical type involving the pairs of less strong Au…S bonds between the adjacent binuclear units. The distorted tetrahedral anions [TlCl4] are localized between the polymeric chains. The study of the thermal behavior of compounds I and II by simultaneous thermal analysis makes it possible to establish the character of thermal transformations of the substances and to identify Tl2S (I), TlCl, and elemental gold (II) as thermolysis products

  • 14.
    Javed, Muhammad Asadullah
    et al.
    NMR Research Unit, University of Oulu.
    Ahola, Susanna
    NMR Research Unit, University of Oulu.
    Håkansson, Pär
    NMR Research Unit, University of Oulu.
    Mankinen, Otto
    NMR Research Unit, University of Oulu.
    Aslam, Muhammad Kamran
    NMR Research Unit, University of Oulu.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskih, Sergei
    System and Component Design, Department of Machine Design, KTH Royal Institute of Technology.
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Telkki, Ville-Veikko
    NMR Research Unit, University of Oulu.
    Y Structure and dynamics elucidation of ionic liquids using multidimensional Laplace NMR2017In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 53, no 80, p. 11056-11059Article in journal (Refereed)
    Abstract [en]

    We demonstrate the ability of multidimensional Laplace NMR (LNMR), comprising relaxation and diffusion experiments, to reveal essential information about microscopic phase structures and dynamics of ionic liquids that is not observable using conventional NMR spectroscopy or other techniques.

  • 15.
    Farzaneh, Amirfarrokh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bacsik, Zoltan
    Department of Materials and Environmental Chemistry, Stockholm University.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Adsorption of Butanol and Water Vapors in Silicalite‑1 Films with a Low Defect Density2016In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, p. 11789-11798Article in journal (Refereed)
    Abstract [en]

    Pure silica zeolites are potentially hydrophobic and have therefore been considered to be interesting candidates for separating alcohols, e.g., 1-butanol, from water. Zeolites are traditionally synthesized at high pH, leading to the formation of intracrystalline defects in the form of silanol defects in the framework. These silanol groups introduce polar adsorption sites into the framework, potentially reducing the adsorption selectivity toward alcohols in alcohol/water mixtures. In contrast, zeolites prepared at neutral pH using the fluoride route contain significantly fewer defects. Such crystals should show a much higher butanol/water selectivity than crystals prepared in traditional hydroxide (OH−) media. Moreover, silanol groups are present at the external surface of the zeolite crystals; therefore, minimizing the external surface of the studied adsorbent is important. In this work, we determine adsorption isotherms of 1-butanol and water in silicalite-1 films prepared in a fluoride (F−) medium using in situ attenuated total reflectance−Fourier transform infrared (ATR−FTIR) spectroscopy. This film was composed of well intergrown, plate-shaped b-oriented crystals, resulting in a low external area. Single-component adsorption isotherms of 1-butanol and water were determined in the temperature range of 35− 80 °C. The 1-butanol isotherms were typical for an adsorbate showing a high affinity for a microporous material and a large increase in the amount adsorbed at low partial pressures of 1-butanol. The Langmuir−Freundlich model was successfully fitted to the 1-butanol isotherms, and the heat of adsorption was determined. Water showed a very low affinity for the adsorbent, and the amounts adsorbed were very similar to previous reports for large silicalite-1 crystals prepared in a fluoride medium. The sample also adsorbed much less water than did a reference silicalite-1(OH−) film containing a high density of internal defects.The results show that silicalite-1 films prepared in a F− medium with a low density of defects and external area are very promising for the selective recovery of 1-butanol from aqueous solutions.

  • 16.
    Wei, Juan
    et al.
    Department of Chemistry and Department of Physics, University of Warwick, Coventry.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Iuga, Dinu
    Department of Physics, Warwick University, Coventry, Department of Chemistry and Department of Physics, University of Warwick, Coventry.
    Lam, Pui Yiu
    Department of Chemistry and Department of Physics, University of Warwick, Coventry.
    Barrow, Mark P.
    Department of Chemistry and Department of Physics, University of Warwick, Coventry.
    Dupree, Ray
    University of Warwick, Department of Physics, Warwick University, Coventry, Department of Chemistry and Department of Physics, University of Warwick, Coventry.
    Brown, Steven P.
    Department of Physics, Warwick University, Coventry, Department of Chemistry and Department of Physics, University of Warwick, Coventry.
    O'Connor, Peter B.
    Department of Chemistry and Department of Physics, University of Warwick, Coventry.
    Amyloid Hydrogen Bonding Polymorphism Evaluated by 15N{17O}REAPDOR Solid-State NMR and Ultra-High Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry2016In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 55, no 14, p. 2065-2068Article in journal (Refereed)
    Abstract [en]

    A combined approach, using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and solid-state NMR (Nuclear Magnetic Resonance), shows a high degree of polymorphism exhibited by Aβ species in forming hydrogen-bonded networks. Two Alzheimer’s Aβ peptides, Ac-Aβ16–22-NH2 and Aβ11–25, selectively labeled with 17O and 15N at specific amino acid residues were investigated. The total amount of peptides labeled with 17O as measured by FTICR-MS enabled the interpretation of dephasing observed in 15N{17O}REAPDOR solid-state NMR experiments. Specifically, about one-third of the Aβ peptides were found to be involved in the formation of a specific >C═17O···H–15N hydrogen bond with their neighbor peptide molecules, and we hypothesize that the rest of the molecules undergo ± n off-registry shifts in their hydrogen bonding networks.

  • 17.
    Wang, Yonglei
    et al.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Shimpi, Manishkumar
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sarman, Sten S.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    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.
    Kloo, Lars
    Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology.
    Laaksonen, Aatto
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Atomistic insight into tetraalkylphosphonium-bis(oxalato)borate ionic liquid/water mixtures: 2. Volumetric and Dynamic Properties2016In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 120, no 30, p. 7446-7455Article in journal (Refereed)
    Abstract [en]

    Atomistic simulations have been performed to investigate the microscopic structural organization of aqueous solutions of trihexyltetradecylphosphonium bis(oxalato)borate ([P6,6,6,14][BOB]) ionic liquid (IL). The evolution of the microscopic liquid structure and the local ionic organization of IL/water mixtures as a function of the water concentration is visualized and systematically analyzed via radial and spatial distribution functions, coordination numbers, hydrogen bond network, and water clustering analysis. The microscopic liquid structure in neat IL is characterized by a connected apolar network composed of the alkyl chains of [P6,6,6,14] cations and isolated polar domains consisting of the central segments of [P6,6,6,14] cations and [BOB] anions, and the corresponding local ionic environment is described by direct contact ion pairs. In IL/water mixtures with lower water mole fractions, the added water molecules are dispersed and embedded in cavities between neighboring ionic species and the local ionic structure is characterized by solvent-shared ion pairs through cation-water-anion triple complexes. With a gradual increase in the water concentration in IL/water mixtures, the added water molecules tend to aggregate and form small clusters, intermediate chain-like structures, large aggregates, and eventually a water network in water concentrated simulation systems. A further progressive dilution of IL/water mixtures leads to the formation of self-organized micelle-like aggregates characterized by a hydrophobic core and hydrophilic shell consisting of the central polar segments in [P6,6,6,14] cations and [BOB] anions in a highly branched water network. The striking structural evolution of the [P6,6,6,14][BOB] IL/water mixtures is rationalized by the competition between favorable hydrogen bonded interactions and strong electrostatic interactions between the polar segments in ionic species and the dispersion interactions between the hydrophobic alkyl chains in [P6,6,6,14] cations

  • 18.
    Gowda, Vasantha
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Laitinen, Risto S.
    Laboratory of Inorganic Chemistry, University of Oulu.
    Telkki, Ville-Veikko
    NMR Research Unit, University of Oulu.
    Larsson, Anna-Carin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Lantto, Perttu
    NMR Research Unit, University of Oulu.
    DFT calculations in the assignment of solid-state NMR and crystal structure elucidation of a lanthanum(iii) complex with dithiocarbamate and phenanthroline2016In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, no 48, p. 19473-19484Article in journal (Refereed)
    Abstract [en]

    The molecular, crystal, and electronic structures as well as spectroscopic properties of a mononuclear heteroleptic lanthanum(iii) complex with diethyldithiocarbamate and 1,10-phenanthroline ligands (3 : 1) were studied by solid-state 13C and 15N cross-polarisation (CP) magic-angle-spinning (MAS) NMR, X-ray diffraction (XRD), and first principles density functional theory (DFT) calculations. A substantially different powder XRD pattern and 13C and 15N CP-MAS NMR spectra indicated that the title compound is not isostructural to the previously reported analogous rare earth complexes with the space group P21/n. Both 13C and 15N CP-MAS NMR revealed the presence of six structurally different dithiocarbamate groups in the asymmetric unit cell, implying a non-centrosymmetric packing arrangement of molecules. This was supported by single-crystal X-ray crystallography showing that the title compound crystallised in the triclinic space group P1[combining macron]. In addition, the crystal structure also revealed that one of the dithiocarbamate ligands has a conformational disorder. NMR chemical shift calculations employing the periodic gauge including projector augmented wave (GIPAW) approach supported the assignment of the experimental 13C and 15N NMR spectra. However, the best correspondences were obtained with the structure where the atomic positions in the X-ray unit cell were optimised at the DFT level. The roles of the scalar and spin-orbit relativistic effects on NMR shielding were investigated using the zeroth-order regular approximation (ZORA) method with the outcome that already the scalar relativistic level qualitatively reproduces the experimental chemical shifts. The electronic properties of the complex were evaluated based on the results of the natural bond orbital (NBO) and topology of the electron density analyses. Overall, we apply a multidisciplinary approach acquiring comprehensive information about the solid-state structure and the metal-ligand bonding of the heteroleptic lanthanum complex.

  • 19.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Kotenkov, Sergey A.
    Kazan (Volga Region) Federal University, Kazan, Institute of Physics, Kazan (Volga Region) Federal University.
    Munavirov, Bulat
    Kazan (Volga Region) Federal University, Kazan, Institute of Physics, Kazan (Volga Region) Federal University.
    Khaliulina, Aliya V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Gnezdilov, Oleg I.
    Kazan (Volga Region) Federal University, Kazan, Institute of Physics, Kazan (Volga Region) Federal University.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Effect of curcumin on lateral diffusion in lipid bilayers2016In: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 26, no 2, p. 109-110Article in journal (Refereed)
    Abstract [en]

    Lateral diffusion in dimyristoylphosphatidylcholine lipid bilayers decreases in the presence of cholesterol and curcumin, as measured by 1H NMR spectroscopy, but the mechanisms of action of these two compounds are different.

  • 20.
    Roukala, Juho
    et al.
    NMR Research Unit, University of Oulu .
    Orr, Simon T.
    Department of Physics, The University of Warwick.
    Hanna, John V.
    Department of Physics, The University of Warwick.
    Vaara, Juha
    NMR Research Unit, University of Oulu .
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences .
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Lantto, Perttu
    NMR Research Unit, University of Oulu .
    Experimental and First-Principles NMR Analysis of Pt(II) Complexes With O,O'-Dialkyldithiophosphate Ligands2016In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 120, no 42, p. 8326-8338Article in journal (Refereed)
    Abstract [en]

    Polycrystalline bis(dialkyldithiophosphato)Pt(II) complexes of the form [Pt{S2P(OR)2}2] (R = ethyl, iso-propyl, iso-butyl, sec-butyl or cyclo-hexyl group) were studied using solid-state 31P and 195Pt NMR spectroscopy, to determine the influence of R to the structure of the central chromophore. The measured anisotropic chemical shift (CS) parameters for 31P and 195Pt afford more detailed chemical and structural information, as compared to isotropic CS and J couplings alone. Advanced theoretical modeling at the hybrid DFT level, including both crystal lattice and the important relativistic spin-orbit effects qualitatively reproduced the measured CS tensors, supported the experimental analysis, and provided extensive orientational information. A particular correction model for the non-negligible lattice effects was adopted, allowing one to avoid a severe deterioration of the 195Pt anisotropic parameters due to the high requirements posed on the pseudopotential quality in such calculations. Though negligible differences were found between the 195Pt CS tensors with different substituents R, the 31P CS parameters differed significantly between the complexes, implying the potential to distinguish between them. The presented approach enables good resolution and a detailed analysis of heavy-element compounds by solid-state NMR, thus widening the understanding of such systems.

  • 21.
    Karimi, Somayeh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Korelskiy, Danil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mortazavi, Yadollah
    Catalysis and Nanostructured Materials Research Laboratory, College of Engineering, School of Chemical Engineering, University of Tehran.
    Khodadadi, Abbas Ali
    Catalysis and Nanostructured Materials Research Laboratory, College of Engineering, School of Chemical Engineering, University of Tehran.
    Sardari, Kaymar
    Catalysis and Nanostructured Materials Research Laboratory, College of Engineering, School of Chemical Engineering, University of Tehran.
    Esmaeili, Mohammad
    Catalysis and Nanostructured Materials Research Laboratory, College of Engineering, School of Chemical Engineering, University of Tehran.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    High flux acetate functionalized silica membranes based on in-situ co-condensation for CO2/N2 separation2016In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 520, p. 574-582Article in journal (Refereed)
    Abstract [en]

    Acetate-functionalized silica membranes were prepared via co-condensation. The molar ratio of functional groups in the silica matrix was varied in the range of 0–0.6, denoted by x. The presence of functional groups bonded to the silica network was revealed by FTIR and 29Si and 13C solid-state NMR analysis. The stability of the groups was studied by TG analysis. The membranes were evaluated for CO2/N2 mixture separation in a temperature range of 253–373 K using a feed pressure of 9 bar and a sweep gas kept at atmospheric pressure on the permeate side. The membranes were found to be CO2-selective at all the conditions studied. The highest observed selectivity was 16 for x=0.4, with a CO2 permeance of 5.12×10−7 mol s−1 m−2 Pa−1. For x=0.2, a permeance of as high as 20.74×10−7 mol s−1 m−2 Pa−1 with a CO2/N2 selectivity of 7.5 was obtained. This permeance is the highest reported for CO2/N2 separation using functionalized silica membranes. It is proposed that the separation mechanism between CO2 and N2 was the preferential adsorption of CO2, which inhibited adsorption and permeation of N2 through the silica pore network. Permporometry results revealed that as the loading of functional groups increased, the He permeance decreased. It was also indicated that the quantity of micropores in the functionalized membrane was higher than that in the parent silica membrane.

  • 22.
    Trublet, Mylene
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Maslova, Marina V.
    Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Science Center, Russian Academy of Sciences.
    Rusanova-Naydenova, Daniela
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mild syntheses and surface characterization of amorphous TiO(OH)(H2PO4)·H2O ion-exchanger2016In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 183, p. 467-475Article in journal (Refereed)
    Abstract [en]

    This work focuses on the synthesis of titanium phosphate (TiP1) ion-exchanger containing solely H2PO4-groups. Based on the elemental analyses, TG, 31P MAS NMR, XRD and Raman data, the formula TiO(OH)(H2PO4)·H2O is assigned to TiP1. The synthesis requires a mild heating at 70–80 °C for a short period of time, followed by filtration and HCl-washing of the TiP1 powder. The layered nature and low crystallinity of this sorbent is confirmed by powder XRD technique. The existence of micro and mesopores in the material is established using BET method. The Na+ capacity of TiP1 is determined to be 6.3 meq g−1 which is the highest value reported for H2PO4-based sorbents. The presence of H2PO4 groups is expected to considerably increase both the pH-working range of the TiP1 sorbent and its exchange capacity towards divalent metal ions. All data for TiP1 are compared to the data for amorphous TiP containing mostly HPO4 groups.

  • 23.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Azancheev, Nail
    Kazan (Volga Region) Federal University, Kazan.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskikh, Sergei
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Self-Diffusion of Phosphonium Bis(Salicylato)Borate Ionic Liquid in Pores of Vycor Porous Glass2016In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 230, p. 128-134Article in journal (Refereed)
    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.

  • 24.
    Shah, Faiz Ullah
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Khan, Muhammad Saif Ullah
    Department of Chemistry, Quaid-i-Azam University, Islamabad.
    Akhter, Zareen
    Department of Chemistry, Quaid-i-Azam University, Islamabad.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Solid-state 13C, 15N and 29Si NMR characterization of block copolymers with CO2 capture properties2016In: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 54, no 9, p. 734-739Article in journal (Refereed)
    Abstract [en]

    Natural abundance solid-state multinuclear (13C, 15N and 29Si) cross-polarization magic-angle-spinning NMR was used to study structures of three block copolymers based on polyamide and dimethylsiloxane and two polyamides, one of which including ferrocene in its structure. Assignment of most of the resonance lines in 13C, 15N and 29Si cross-polarization magic angle-spinning NMR spectra were suggested. A comparative analysis of 13C isotropic chemical shifts of polyamides with and without ferrocene has revealed a systematic shift towards higher δ -values (de-shielding) explained as the incorporation of paramagnetic ferrocene into the polyamide backbone. In addition, the 13C NMR resonance lines for ferrocene-based polyamide were significantly broadened, because of paramagnetic effects from ferrocene incorporated in the structure of this polyamide polymer. Single resonance lines with chemical shifts ranging from 88.1 to 91.5ppm were observed for 15N sites in all of studied polyamide samples. 29Si chemical shifts were found to be around 22.4ppm in polydimethylsiloxane samples that falls in the range of chemical shifts for alkylsiloxane compounds. The CO2 capture performance of polyamide-dimethylsiloxane-based block copolymers was measured as a function of temperature and pressure. The data revealed that these polymeric materials have potential to uptake CO2 (up to 9.6 cm3 g1) at ambient pressures and in the temperature interval 30–40 °C. Copyright ©2016 John Wiley & Sons, Ltd.

  • 25.
    Wang, Y.L.
    et al.
    Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology.
    Sarman, Sten
    Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology.
    Kloo, Lars
    Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskih, Sergei
    System and Component Design, Department of Machine Design, KTH Royal Institute of Technology.
    Laaksonen, Aatto
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Solvation structures of water in trihexyltetradecylphosphonium-orthoborate ionic liquids2016In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 145, no 6, article id 064507Article in journal (Refereed)
    Abstract [en]

    Atomistic molecular dynamics simulations have been performed to investigate effective interactions of isolated water molecules dispersed in trihexyltetradecylphosphonium-orthoborate ionic liquids (ILs). The intrinsic free energy changes in solvating one water molecule from gas phase into bulk IL matrices were estimated as a function of temperature, and thereafter, the calculations of potential of mean force between two dispersed water molecules within different IL matrices were performed using umbrella sampling simulations. The systematic analyses of local ionic microstructures, orientational preferences, probability and spatial distributions of dispersed water molecules around neighboring ionic species indicate their preferential coordinations to central polar segments in orthoborate anions. The effective interactions between two dispersed water molecules are partially or totally screened as their separation distance increases due to interference of ionic species in between. These computational results connect microscopic anionic structures with macroscopically and experimentally observed difficulty in completely removing water from synthesized IL samples and suggest that the introduction of hydrophobic groups to central polar segments and the formation of conjugated ionic structures in orthoborate anions can effectively reduce residual water content in the corresponding IL samples

  • 26.
    Gowda, Vasantha
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sarma, Bipul
    Department of Chemical Sciences, Division of Chemical Engineering, Tezpur University, Tezpur, Assam.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Telkki, Ville-Veikko
    University of Oulu, NMR Research Group, Division of Chemical Engineering, Faculty of Science, University of Oulu.
    Larsson, Anna-Carin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Lantto, Perttu
    University of Oulu, NMR Research Group, Division of Chemical Engineering, Faculty of Science, University of Oulu.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Structure Elucidation of an Yttrium Diethyldithiocarbamato-Phenanthroline Complex by X-ray Crystallography, Solid-State NMR, and ab-initio Quantum Chemical Calculations2016In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 20, p. 3278-3291Article in journal (Refereed)
    Abstract [en]

    We present a structural analysis method for molecular and electronic structure of yttrium diethyldithiocarbamato-phenanthroline complex {[Y(S2CNR2)3PHEN] with R = C2H5 and PHEN = 1,10-phenanthroline} combining solid-state NMR spectroscopy, XRD, and first principles DFT calculations. Replacing the Nd3+ ion with Y3+ in the reported crystal structure of [Nd(S2CNR2)3PHEN] complex generated an approximate 3D structure of the title complex. The structure was then subjected to first principles quantum chemical geometry optimisation using periodic DFT method. The quality of the method is discussed by comparing predicted and experimental powder XRD patterns. Full assignment of 13C and 15N solid-state CP-MAS NMR spectra as well as analyses of the principal values of the chemical shift tensors were carried out using periodic scalar relativistic DFT modelling. Spin-orbit relativistic effects, estimated by SO-ZORA formalism for one molecular unit, were evaluated. Finally, the X-ray structure of the title complex was determined, which proved that the former procedure is appropriate. The most important orbital interactions were investigated by Natural Bond Orbital analysis. The isotropic shielding values for S2CN-carbons were analysed by Natural Localised Molecular Orbital analysis. The present approach can be further extended to study other rare earth metal complexes, particularly those having similar but not yet solved crystal structures

  • 27.
    Ivanov, Alexander V.
    et al.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Bredyuk, O.A.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Loseva, Olga V.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Synthesis, Supramolecular Self-Organization, and Thermal Behavior of Gold(III)–Thallium(III) Heteronuclear Complexes ([Au{S2CN(CH3)2}2][TlCl4])2 and ([Au{S2CN(C2H5)2}2][TlCl4]) n2016In: Russian Journal of Inorganic Chemistry, ISSN 0036-0236, E-ISSN 1531-8613, Vol. 61, no 6, p. 755-765Article in journal (Refereed)
    Abstract [en]

    The interaction of polymeric thallium(I) dimethyl- and diethyldithiocarbamates with [AuCl4]– in 2 M HCl has been studied. Heteropolynuclear complexes ([Au{S2CN(CH3)2}2][TlCl4])2 (I) and ([Au{S2CN(C2H5)2}2][TlCl4]) n (II) have been preparatively isolated from chemisorption systems [Tl2{S2CNR2}2] n –Au3+/2 M HCl (R = CH3, C2H5). These compounds have been characterized by 13C CP/MAS NMR, and their crystal and supramolecular structures have been determined by X-ray crystallography. Basic structural units of compounds I and II are square-planar [Au{S2CNR2}2]+ cations (with S,S'- bidentate coordination of two Dtc ligands to the gold atom) and distorted tetrahedral [TlCl4]–anions. In supramolecular self-organization, the decisive role is played by relatively weak secondary interactions Au⋯S and Au⋯Cl. With the use of simultaneous thermal analysis, the thermal behavior of I and II have been studied, which enabled the elucidation of temperature-induced transformations and identification of TlCl and reduced gold among the thermolysis products.

  • 28.
    Ruyter-Hooley, Maika
    et al.
    La Trobe University.
    Larsson, Anna-Carin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Johnson, Bruce B.
    La Trobe University.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Angove, Michael J.
    La Trobe University.
    The effect of inositol hexaphosphate on cadmium sorption to gibbsite2016In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 474, p. 159-170Article in journal (Refereed)
    Abstract [en]

    HypothesisOxides, hydrous oxides and hydroxides of aluminium and iron are important in determining the availability of trace and heavy metals in soil systems. The presence of complexing anions is also known to affect the binding of these metals in soils. Since organophosphates, such as inositol hexaphosphate (IP6), are present in most soil systems they are expected to affect the nature of the interaction between metal ions and metal (hyr)oxides.ExperimentsBoth adsorption edge and isotherm experiments were conducted on Cd(II)–gibbsite and Cd(II)–IP6–gibbsite systems. In addition, solid-state 31P MAS NMR measurements were performed on the ternary system. All results were used to develop Extended Constant Capacitance surface complexation models of both the Cd(II)–gibbsite and IP6–Cd(II)–gibbsite sorption systems.FindingsThe presence of IP6 significantly increased sorption of Cd(II) to gibbsite below pH 8 especially at higher concentrations of Cd(II) and IP6. The 31P MAS NMR spectra, together with surface complexation modeling, indicated the presence of two outer-sphere ternary complexes with the first, [(SOH2)33+–(LHCd)9-]6-, important at relatively low concentrations, while the second, [SLH38-−Cd2+]6-, dominated sorption at higher sorbate concentrations. Thus the presence of organophosphates in soil systems increases sorption and may therefore decrease the availability of trace and heavy metals to plants.

  • 29.
    Golets, M.
    et al.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Shimpi, Manishkumar
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Wang, Y-L
    Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    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.
    Laaksonen, Aatto
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Understanding the thermal decomposition mechanism of a halogen-free chelated orthoborate-based ionic liquid: a combined computational and experimental study2016In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, p. 22458-22466Article in journal (Refereed)
    Abstract [en]

    In the last few decades, ionic liquids (ILs) have gained significant attention as lubricants and lubricant additives due to their polar nature, low vapour pressure and tunable physicochemical properties. In this work, quantum chemistry calculations and atomistic Molecular Dynamics (MD) simulations were employed to predict thermal degradation mechanisms of a potential lubricating agent - the tributyloctylphosphonium bis(oxalato)borate ([P4,4,4,8][BOB]) IL. It was found that the onset of decomposition of the studied IL coincides with a cleavage of the B-O bonds in the [BOB](-) anion. Consequently, a series of chemical reactions of the [P4,4,4,8](+) cation with the [BOB](-) anion was triggered yielding alkylboranes, alkenes, trialkylphosphines, CO and CO2. Another ionic system, consisting of [P4,4,4,8][Cl], was also tested for a comparison. Thermogravimetric measurements have shown a higher thermal stability of [P4,4,4,8][BOB] compared to that of [P4,4,4,8][Cl] at least at the initial stage of decomposition, in accord with the presented calculations. Quantum chemical frequency calculations also agreed with the experimental Fourier Transform Infrared (FTIR) spectroscopy results.

  • 30.
    Wang, Yonglei
    et al.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Sarman, Sten S.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm 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.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rutland, Mark W.
    Surface and Corrosion Science, School of Chemical Science and Engineering, KTH – Royal Institute of Technology, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Laaksonen, Aatto
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Atomistic insight into tetraalkylphosphonium-bis(oxalato)borate ionic liquid/water mixtures: I. Local microscopic structure2015In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 119, no 16, p. 5251-5264Article in journal (Refereed)
    Abstract [en]

    Atomistic simulations have been performed to investigate the microscopic structural organization of aqueous solutions of trihexyltetradecylphosphonium bis(oxalato)borate ([P6,6,6,14][BOB]) ionic liquid (IL). The evolution of the microscopic liquid structure and the local ionic organization of IL/water mixtures as a function of the water concentration is visualized and systematically analyzed via radial and spatial distribution functions, coordination numbers, hydrogen bond network, and water clustering analysis. The microscopic liquid structure in neat IL is characterized by a connected apolar network composed of the alkyl chains of [P6,6,6,14] cations and isolated polar domains consisting of the central segments of [P6,6,6,14] cations and [BOB] anions, and the corresponding local ionic environment is described by direct contact ion pairs. In IL/water mixtures with lower water mole fractions, the added water molecules are dispersed and embedded in cavities between neighboring ionic species and the local ionic structure is characterized by solvent-shared ion pairs through cation-water-anion triple complexes. With a gradual increase in the water concentration in IL/water mixtures, the added water molecules tend to aggregate and form small clusters, intermediate chain-like structures, large aggregates, and eventually a water network in water concentrated simulation systems. A further progressive dilution of IL/water mixtures leads to the formation of self-organized micelle-like aggregates characterized by a hydrophobic core and hydrophilic shell consisting of the central polar segments in [P6,6,6,14] cations and [BOB] anions in a highly branched water network. The striking structural evolution of the [P6,6,6,14][BOB] IL/water mixtures is rationalized by the competition between favorable hydrogen bonded interactions and strong electrostatic interactions between the polar segments in ionic species and the dispersion interactions between the hydrophobic alkyl chains in [P6,6,6,14] cations

  • 31.
    Zhou, Han
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Farzaneh, Amirfarrokh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Colloidal Defect-Free Silicalite-1 Single Crystals: Preparation, Structure Characterization, Adsorption, and Separation Properties for Alcohol/Water Mixtures2015In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, no 30, p. 8488-8494Article in journal (Refereed)
    Abstract [en]

    In this work, colloidal silicalite-1 single crystals are for the first time synthesized using fluoride as mineralizing agent at near neutral pH. SEM, TEM, DLS, XRD, solid-state 29Si MAS NMR, and adsorption/desorption experiments using nitrogen, water, n-butanol, and ethanol as adsorbates were used to characterize the crystals. The single crystals have a platelike habit with a length of less than 170 nm and an aspect ratio (length/width) of about 1.2, and the thickness of the crystals is less than 40 nm. Compared with silicalite-1 crystals grown using hydroxide as mineralizing agent, the amount of structural defects in the lattice is significantly reduced and the hydrophobicity is increased. Membrane separation and adsorption results show that the synthesized defect-free crystals present high selectivity to alcohols from alcohol/water mixtures. The n-butanol/water adsorption selectivities were ca. 165 and 14 for the defect-free crystals and a reference sample containing defects, respectively, illustrating the improvement in n-butanol/water selectivity by eliminating the polar silanol defects.

  • 32.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Azancheev, Nail
    Kazan (Volga Region) Federal University, Kazan.
    Taher, Mamoun
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Self-diffusion and interactions in mixtures of imidazolium bis(mandelato)borate ionic liquids with polyethylene glycol: 1H NMR study2015In: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 53, no 7, p. 493-497Article in journal (Refereed)
    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

  • 33.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    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 Infectivity2015In: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 46, no 7, p. 757-769Article in journal (Refereed)
    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).

  • 34.
    Rodina, Tatyana A.
    et al.
    Amur State University, Blagoveshchensk, Russian Federation, Amur Institute of Integrated Research, Far East Division, Russian Academy of Sciences, Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Korneeva, Eugenia V.
    Far Eastern Branch of the Russian Academy of Sciences, 675000, Blagoveschensk, Amur Region, Amur Institute of Integrated Research, Far East Division, Russian Academy of Sciences, Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Supramolecular self-organisation and conformational isomerism of a binuclear O,O’-dipropyl dithiophosphate gold(I) complex, [Au2{S2P(OC3H7)2}2]: Synthesis, 13C and 31P CP/MAS NMR spectroscopy, single-crystal X-ray diffraction study and thermal behaviour2015In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 149, p. 881-888Article in journal (Refereed)
    Abstract [en]

    Crystalline one-dimensional polymeric catena-poly[bis(μ2-O,O’-dipropyldithiophosphato-S,S’)digold(I)] (Au–Au) (1) was prepared and studied using 13C and 31P CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. To elucidate the structural function of Dtph ligands in crystalline gold(I) O,O’-dipropyl dithiophosphate, the chemical shift anisotropy parameters (δaniso and η) were calculated from spinning sideband manifolds in 31P MAS NMR spectra. A novel structure of the gold(I) compound comprises two isomeric, non-centrosymmetric binuclear molecules of [Au2{S2P(OC3H7)2}2] (isomers ‘A’ and ‘B’), whose four Dtph groups display structural inequivalence. In each isomeric binuclear molecule of 1, a pair of μ2-bridging dipropyl Dtph ligands almost symmetrically links two neighbouring gold atoms, forming an extensive eight-membered metallocycle [Au2S4P2], while the intramolecular aurophilic Au···Au bond additionally stabilises this central cyclic moiety. At the supramolecular level of complex 1, intermolecular aurophilic Au⋅⋅⋅Au bonds yield almost linear infinite polymeric chains (⋅⋅⋅‘A’⋅⋅⋅‘B’⋅⋅⋅‘A’⋅⋅⋅‘B’⋅⋅⋅)n. The thermal behaviour of this compound was studied by the simultaneous thermal analysis (STA) technique (a combination of TG and DSC) under an argon atmosphere

  • 35.
    Ruyter-Hooley, Maika
    et al.
    La Trobe University.
    Larsson, Anna-Carin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Johnson, Bruce B.
    La Trobe University.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Angove, Michael J.
    La Trobe University.
    Surface complexation modeling of inositol hexaphosphate sorption onto gibbsite2015In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 440, p. 282-291Article in journal (Refereed)
    Abstract [en]

    The sorption of Inositol hexaphosphate (IP6) onto gibbsite was investigated using a combination of adsorption experiments, 31P solid-state MAS NMR spectroscopy, and surface complexation modelling. Adsorption experiments conducted at four temperatures showed that IP6 sorption decreased with increasing pH. At pH 6, IP6 sorption increased with increasing temperature, while at pH 10 sorption decreased as the temperature was raised. 31P MAS NMR measurements at pH 3, 6, 9 and 11 produced spectra with broad resonance lines that could be de-convoluted with up to five resonances (+5, 0, -6, -13 and -21 ppm). The chemical shifts suggest the sorption process involves a combination of both outer- and inner-sphere complexation and surface precipitation. Relative intensities of the observed resonances indicate that outer-sphere complexation is important in the sorption process at higher pH, while inner-sphere complexation and surface precipitation are dominant at lower pH. Using the adsorption and 31P MAS NMR data, IP6 sorption to gibbsite was modelled with an Extended Constant Capacitance Model (ECCM). The adsorption reactions that best described the sorption of IP6 to gibbsite included two inner-sphere surface complexes and one outer-sphere complex:

  • 36.
    Lendel, Christofer
    et al.
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    Bjerring, Morten
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    Dubnovitsky, Anatoly
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    Kelly, Robert T.
    Department of Physics, Warwick University, Coventry.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Nielsen, Niels Chr.
    Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University.
    Härd, Torleif
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    A Hexameric Peptide Barrel as Building Block of Amyloid-β Protofibrils2014In: Angewandte Chemie, ISSN 0044-8249, E-ISSN 1521-3757, Vol. 126, no 47, p. 12970-12974Article in journal (Refereed)
    Abstract [en]

    Oligomeric and protofibrillar aggregates formed by the amyloid-β peptide (Aβ) are believed to be involved in the pathology of Alzheimer’s disease. Central to Alzheimer pathology is also the fact that the longer Aβ42 peptide is more prone to aggregation than the more prevalent Aβ40. Detailed structural studies of Aβ oligomers and protofibrils have been impeded by aggregate heterogeneity and instability. We previously engineered a variant of Aβ that forms stable protofibrils and here we use solid-state NMR spectroscopy and molecular modeling to derive a structural model of these. NMR data are consistent with packing of residues 16 to 42 of Aβ protomers into hexameric barrel-like oligomers within the protofibril. The core of the oligomers consists of all residues of the central and C-terminal hydrophobic regions of Aβ, and hairpin loops extend from the core. The model accounts for why Aβ42 forms oligomers and protofibrils more easily than Aβ40.

  • 37.
    Lendel, Christofer
    et al.
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    Bjerring, Morten
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    Dubnovitsky, Anatoly
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    Kelly, Robert T.
    Department of Physics, Warwick University, Coventry.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Nielsen, Niels Chr.
    Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University.
    Härd, Torleif
    Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences (SLU).
    A Hexameric Peptide Barrel as Building Block of Amyloid-β Protofibrils2014In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 126, no 47, p. 12970-12974Article in journal (Refereed)
    Abstract [en]

    Oligomeric and protofibrillar aggregates formed by the amyloid-β peptide (Aβ) are believed to be involved in the pathology of Alzheimer’s disease. Central to Alzheimer pathology is also the fact that the longer Aβ42 peptide is more prone to aggregation than the more prevalent Aβ40. Detailed structural studies of Aβ oligomers and protofibrils have been impeded by aggregate heterogeneity and instability. We previously engineered a variant of Aβ that forms stable protofibrils and here we use solid-state NMR spectroscopy and molecular modeling to derive a structural model of these. NMR data are consistent with packing of residues 16 to 42 of Aβ protomers into hexameric barrel-like oligomers within the protofibril. The core of the oligomers consists of all residues of the central and C-terminal hydrophobic regions of Aβ, and hairpin loops extend from the core. The model accounts for why Aβ42 forms oligomers and protofibrils more easily than Aβ40.

  • 38.
    Hall, Colin J.
    et al.
    Ian Wark Research Institute, University of South Australia.
    Ponnusamy, Thirunavukkarasu
    Ian Wark Research Institute, University of South Australia.
    Murphy, Peter J.
    Mawson Institute, University of South Australia.
    Lindberg, Mats
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Griesser, Hans J.
    Mawson Institute, University of South Australia.
    A solid-state nuclear magnetic resonance study of post-plasma reactions in organosilicone microwave plasma-enhanced chemical vapor deposition (PECVD) coatings2014In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, no 11, p. 8353-8362Article in journal (Refereed)
    Abstract [en]

    Plasma-polymerized organosilicone coatings can be used to impart abrasion resistance and barrier properties to plastic substrates such as polycarbonate. Coating rates suitable for industrial-scale deposition, up to 100 nm/s, can be achieved through the use of microwave plasma-enhanced chemical vapor deposition (PECVD), with optimal process vapors such as tetramethyldisiloxane (TMDSO) and oxygen. However, it has been found that under certain deposition conditions, such coatings are subject to post-plasma changes; crazing or cracking can occur anytime from days to months after deposition. To understand the cause of the crazing and its dependence on processing plasma parameters, the effects of post-plasma reactions on the chemical bonding structure of coatings deposited with varying TMDSO-to-O2 ratios was studied with 29Si and 13C solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) using both single-pulse and cross-polarization techniques. The coatings showed complex chemical compositions significantly altered from the parent monomer. 29Si MAS NMR spectra revealed four main groups of resonance lines, which correspond to four siloxane moieties (i.e., mono (M), di (D), tri (T), and quaternary (Q)) and how they are bound to oxygen. Quantitative measurements showed that the ratio of TMDSO to oxygen could shift the chemical structure of the coating from 39% to 55% in Q-type bonds and from 28% to 16% for D-type bonds. Post-plasma reactions were found to produce changes in relative intensities of 29Si resonance lines. The NMR data were complemented by Fourier transform infrared (FTIR) spectroscopy. Together, these techniques have shown that the bonding environment of Si is drastically altered by varying the TMDSO-to-O2 ratio during PECVD, and that post-plasma reactions increase the cross-link density of the silicon-oxygen network. It appears that Si-H and Si-OH chemical groups are the most susceptible to post-plasma reactions. Coatings produced at a low TMDSO-to-oxygen ratio had little to no singly substituted moieties, displayed a highly cross-linked structure, and showed less post-plasma reactions. However, these chemically more stable coatings are less compatible mechanically with plastic substrates, because of their high stiffness

  • 39.
    Wang, Yong-Lei
    et al.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskih, Sergei
    System and Component Design, KTH, Royal Institute of Technology.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Laaksonen, Aatto
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Atomistic insight into orthoborate-based ionic liquids: force field development and evaluation2014In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, no 29, p. 8711-8723Article in journal (Refereed)
    Abstract [en]

    We have developed an all-atomistic force field for a new class of halogen-free chelated orthoboratephosphonium ionic liquids. The force field is based on an AMBER framework with determination of force field parameters for phosphorus and boron atoms, as well as refinement of several available parameters. The bond and angle force constants were adjusted to fit vibration frequency data derived from both experimental measurements and ab initio calculations. The force field parameters for several dihedral angles were obtained by fitting torsion energy profiles deduced from ab initio calculations. To validate the proposed force field parameters, atomistic simulations were performed for 12 ionic liquids consisting of tetraalkylphosphonium cations and chelated orthoborate anions. The predicted densities for neat ionic liquids and the [P6,6,6,14][BOB] sample, with a water content of approximately 2.3−2.5 wt %, are in excellent agreement with available experimental data. The potential energy components of 12 ionic liquids were discussed in detail. The radial distribution functions and spatial distribution functions were analyzed and visualized to probe the microscopic ionic structures of these ionic liquids. There are mainly four high-probability regions of chelated orthoborate anions distributed around tetraalkylphosphonium cations in the first solvation shell, and such probability distribution functions are strongly influenced by the size of anions.

  • 40.
    Huang, Rick K.
    et al.
    Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, Maryland.
    Baxa, Ulrich
    Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, Maryland.
    Aldrian, Gudrun
    Centre de Recherches de Biochimie Macromoléculaire, CNRS, University of Montpellier 1 and 2.
    Ahmed, Abdullah B.
    Centre de Recherches de Biochimie Macromoléculaire, CNRS, University of Montpellier 1 and 2.
    Wall, Joseph P.
    Department of Biology, Brookhaven National Laboratory, Upton New York.
    Mizuno, Naoko
    Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, Maryland.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Steven, Alasdair C.
    Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, Maryland.
    Kajava, Andrey V.
    Centre de Recherches de Biochimie Macromoléculaire, CNRS, University of Montpellier 1 and 2.
    Conformational Switching in PolyGln Amyloid Fibrils Resulting from a Single Amino Acid Insertion2014In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 106, no 10, p. 2134-2142Article in journal (Refereed)
    Abstract [en]

    The established correlation between neurodegenerative disorders and intracerebral deposition of polyglutamine aggregates motivates attempts to better understand their fibrillar structure. We designed polyglutamines with a few lysines inserted to overcome the hindrance of extreme insolubility and two D-lysines to limit the lengths of β-strands. One is 33 amino acids long (PolyQKd-33) and the other has one fewer glutamine (PolyQKd-32). Both form well-dispersed fibrils suitable for analysis by electron microscopy. Electron diffraction confirmed cross-β structures in both fibrils. Remarkably, the deletion of just one glutamine residue from the middle of the peptide leads to substantially different amyloid structures. PolyQKd-32 fibrils are consistently 10–20% wider than PolyQKd-33, as measured by negative staining, cryo-electron microscopy, and scanning transmission electron microscopy. Scanning transmission electron microscopy analysis revealed that the PolyQKd-32 fibrils have 50% higher mass-per-length than PolyQKd-33. This distinction can be explained by a superpleated β-structure model for PolyQKd-33 and a model with two β-solenoid protofibrils for PolyQKd-32. These data provide evidence for β-arch-containing structures in polyglutamine fibrils and open future possibilities for structure-based drug design.

  • 41.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Kotenkov, Sergey A.
    Kazan (Volga Region) Federal University, Kazan.
    Munavirov, Bulat
    Kazan (Volga Region) Federal University, Kazan.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Effect of Curcumin on Lateral Diffusion of Phosphatidylcholines in Saturated and Unsaturated Bilayers2014In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 35, p. 10686-10690Article in journal (Refereed)
    Abstract [en]

    Curcumin, a dietary polyphenol, is a natural spice with preventive and therapeutic potential for neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Curcumin possesses a spectrum of antioxidant, anti-inflammatory, anticarcinogenic, and antimutagenic properties. Because of this broad spectrum of pharmacological activity, it has been suggested that, like cholesterol, curcumin exerts its effect on a rather basic biological level, such as on lipid bilayers of biomembranes. The effect of curcumin on translational mobility of lipids in biomembranes has not yet been studied. In this work, we used 1H NMR diffusometry to explore lateral diffusion in planar-oriented bilayers of dimyristoylphosphatidylcholine (DMPC) and dioleoylphosphatidylcholine (DOPC) at curcumin concentrations of up to 40 mol % and in the temperature range of 298-333 K. The presence of curcumin at much lower concentrations (∼7 mol %) leads to a decrease in the lateral diffusion coefficient of DOPC by a factor of 1.3 at lower temperatures and by a factor of 1.14 at higher temperatures. For DMPC, the diffusion coefficient decreases by a factor of 1.5 at lower temperatures and by a factor of 1.2 at higher temperatures. Further increasing the curcumin concentration has no effect. Comparison with cholesterol showed that curcumin and cholesterol influence lateral diffusion of lipids differently. The effect of curcumin is determined by its solubility in lipid bilayers, which is as low as 10 mol % that is much less than that of cholesteroĺs 66 mol %.

  • 42.
    Taher, Mamoun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskih, Sergei
    Machine Design, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Halogen-free ionic liquids in lubrication2014Conference paper (Refereed)
    Abstract [en]

    The use of wear-resistant non-ferrous and lightweight materials calls for novel types of lubricants including neat Ionic Liquids (ILs) and ILs as additives to base oils [1-4]. ILs are non-flammable low temperature molten salts, which have negligible volatility and a high thermal stability. However, most of previously studied ILs as promising lubricants contain BF4- or PF6- anions, which are prone to hydrolysis producing corrosive and toxic species. Here we report on the synthesis, physic-chemical and tribological characterisation of halogen-free ILs with cations belonging to different families (phosphonium, pyrrolidinium, imidazolium), combined with different orthoborate anions (bis(mandelato)borate [BMB], bis(salicylato)borate, bis(oxalato)borate, etc). It was found that these types of hf-BILs (both as neat liquids and as additives) outperform a fully formulated engine oil and a neat PEG oil as antiwear and friction reducing lubricants at steel-steel and steel-aluminium contacts.To reveal mechanisms of formation of tribofilms, the mechanochemically induced boundary films on surfaces of Al2O3, MgO and SiO2 in contact with orthoborate-based ILs were characterised using solid-state multinuclear (11B, 31P and 29Si) MAS NMR, FTIR and Raman spectroscopy. It was found that some of these ILs interact with the oxides, in particular, at elevated temperatures. We suggest that the boundary film formation between hf-BILs and -Al2O3, MgO and SiO2 surfaces is a complex process involving various chemical reactions at the solid-liquid interfaces. Self-diffusion of ionic species in orthoborate based ILs and in IL/PEG mixtures as a function of temperature was studied using pulse-field-gradient (PFG) 1H and 31P NMR [5]. It was found that [P66614][BMB] can exist in one or two different liquid “phases” with ionic species having dramatically different (by two orders of magnitude) self-diffusion coefficients: Slowly diffusing phosphonium cations with long and bulky alkyl chains form domains stabilised by hydrophobic interactions in these ILs in the temperature range 20-50 oC, while small orthoborate anions are fast diffusing species at these temperatures [5]. These domains are, however, disrupted by developed molecular motion with the cation-anion complexes having one and the same diffusion coefficient when the IL system is heated above 50oC. A similar phenomenon was also found in some other [BMB] based ILs with pyrrolidinium and imidazolium cations.

  • 43.
    Taher, Mamoun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Baets, Patrick De
    Department of Mechanical Construction and Production, Ghent University.
    Glavatskih, Sergei
    Department of Mechanical Construction and Production, Ghent University.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Halogen-free pyrrolidinium bis(mandelato)borate ionic liquids: some physicochemical properties and lubrication performance as additives to polyethylene glycol2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 58, p. 30617-30623Article in journal (Refereed)
    Abstract [en]

    This work reports on the synthesis and physicochemical characterisation of novel halogen-free boron containing ionic liquids (hf-BILs) with dialkylpyrrolidinium cations [CnC1Pyrr]+, n ¼ 4–14, and bis(mandelato)borate anion [BMB]. All the synthesised compounds are liquids at room temperature. It was found that the thermal properties and density of these hf-BILs are affected by the length of the longest alkyl chain connected to the nitrogen atom in the pyrrolidinium cations. Differential scanning calorimetry measurements revealed that glass transition temperatures of these ionic liquids are in the temperature range from 218 to 241 K. Interestingly, the glass transition temperatures follow the “odd– even” effect related to the number of carbons (n) in one of the alkyl chains of [CnC1Pyrr]+. It was also found that hf-BILs' density decreases with an increase in the alkyl chain length of [CnC1Pyrr]+. It is suggested that the “odd–even” effect is associated with the difference in packing and specific interactions of cations and anions of this class of hf-BILs. Their lubricating properties, as 3 wt% additives in polyethylene glycol (PEG), were evaluated in steel–steel contacts. PEG with hf BILs additive provided significantly lower wear and friction compared to the neat PEG and 5W40 engine oil. It was found that shortening the length of the longest alkyl chain in the cations of [CnC1Pyrr][BMB] significantly reduces frictional losses. Antiwear properties of [CnC1Pyrr][BMB] in PEG follow the same trend.

  • 44.
    Arkhipov, Victor P.
    et al.
    Kazan National Research Technological University.
    Idiyatullin, Zhamil Sh
    Kazan National Research Technological University.
    Potapova, Elisaveta
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Micelles and aggregates of oxyethylated isononylphenols and their extraction properties near cloud point2014In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, no 20, p. 5480-5487Article in journal (Refereed)
    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

  • 45.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Molecular self-diffusion and micellar structure in the aqueous solutions of AF9-10 ethoxylated isononylphenol near a cloud point2014In: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 24, no 5, p. 266-268Article in journal (Refereed)
    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.

  • 46.
    Usachev, Konstatin S.
    et al.
    Kazan (Volga Region) Federal University, Kazan.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Khairutdinov, B.I.
    Kazan (Volga Region) Federal University, Kazan.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Klochkov, V.V.
    Kazan (Volga Region) Federal University, Kazan.
    NMR structure of the Arctic mutation of the Alzheimer’s Aβ(1-40) peptide docked to SDS micelles2014In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1076, p. 518-523Article in journal (Refereed)
    Abstract [en]

    The “Arctic” point mutation of the Alzheimeŕs amyloid β-peptide is a rare mutation leading to an early onset of Alzheimeŕs disease. The peptide may interact with neuronal membranes, where it can provide its toxic effects. We used 2D NMR spectroscopy to investigate the conformation of the “Arctic” mutant of Aβ1-40 Alzheimer’s amyloid peptide in sodium dodecyl sulfate micelle solutions, which are the type of amphiphilic structures mimicking some properties of biomembranes. The study showed that the Arctic mutant of Aβ1-40 interacts with the surface of SDS micelles mainly through the Leu17-Asn27 310-helical region, while the Ile31-Val40 region is buried in the hydrophobic interior of the micelle. In contrast, wild-type Aβ1-40 interacts with SDS micelles through the Lys16-Asp23 α-helical region and Gly29-Met35. Both the Arctic mutant and the wild-type Aβ1-40 peptides interactions with SDS micelles are hydrophobic in nature. Aβ peptides are thought to be capable of forming pores in biomembranes that can cause changes in neuronal and endothelial cell membrane permeability. It has also been shown that Aβ peptides containing the “Arctic” mutation are more neurotoxic and aggregate more readily than the wild-type Aβ peptides at physiological conditions. Here, we propose that the extension of the helical structure of Leu17-Asn27 and a high aliphaticity (neutrality) of the C-terminal region in the Arctic Aβ peptides are consistent with the idea that formation of ion-permeable pores by Aβ oligomers may be one of prevailing mechanisms of a larger neuronal toxicity of the Arctic Aβ compared to the wild-type Aβ peptides, independent of oxidative damage and lipid peroxidation.

  • 47.
    Munavirov, Bulat V.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rudakova, Maya A.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Polyacrylic Acid Modifies Local and Lateral Mobilities in Lipid Membranes2014In: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 35, no 6, p. 848-858Article in journal (Refereed)
    Abstract [en]

    promising polymer for engineering lipid-based drug-delivery vesicles. Its unique properties allow lowering drug dose and delivery the drug close to the site of its release. To design a successful delivery scheme, however, it is important to understand on the molecular scale how the polymer interacts with lipids under various conditions in the human body. Some aspects of the PAA-lipid interaction can be revealed using physical methods, such as differential scanning microscopy, nuclear magnetic resonance spectroscopy, NMR-diffusometry and infrared spectroscopy. This work discusses the use of these techniques as well as the peculiarities of preparing vesicular and microscopically aligned PAA-lipid systems.

  • 48.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    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 solutions2014In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1070, p. 38-42Article in journal (Refereed)
    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.

  • 49.
    Ivanov, A.V.
    et al.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Egorova, I.V.
    Blagoveshchensk State Pedagogical University.
    Ivanov, M.A.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Tsvykh, R.S.
    University of Warwick, Coventry.
    Structure of crystalline bismuth(III) N,N-dipropyldithiocarbamate [Bi{S2CN(C3H7)2}3] according to 13C and 15N MAS NMR and X-ray diffraction analysis: Supramolecular self-organization and conformational isomerism2014In: Doklady. Physical chemistry, ISSN 0012-5016, E-ISSN 1608-3121, Vol. 454, no 1, p. 16-20Article in journal (Refereed)
  • 50.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Taher, Mamoun
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glavatskih, Sergei
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    The effect of the cation alkyl chain length on density and diffusion in dialkylpyrrolidinium bis(mandelato)borate ionic liquids2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 48, p. 26798-26805Article in journal (Refereed)
    Abstract [en]

    The physicochemical properties of ionic liquids are strongly affected by the selective combination of the cations and anions comprising the ionic liquid. In particular, the length of the alkyl chains of ions has a clear influence on the ionic liquid's performance. In this paper, we study the self-diffusion of ions in a series of halogen-free boron-based ionic liquids (hf-BILs) containing bis(mandelato)borate anions and dialkylpyrrolidinium cations with long alkyl chains CnH2n+1 with n from 4 to 14 within a temperature range of 293-373 K. It was found that the hf-BILs with n = 4-7 have very similar diffusion coefficients, while hf-BILs with n = 10-14 exhibit two liquid sub-phases in almost the entire temperature range studied (293-353 K). Both liquid sub-phases differ in their diffusion coefficients, while values of the slower diffusion coefficients are close to those of hf-BILs with shorter alkyl chains. To explain the particular dependence of diffusion on the alkyl chain length, we examined the densities of the hf-BILs studied here. It was shown that the dependence of the density on the number of CH2 groups in long alkyl chains of cations can be accurately described using a "mosaic type" model, where regions of long alkyl chains of cations (named 'aliphatic' regions) and the residual chemical moieties in both cations and anions (named 'ionic' regions) give additive contributions. Changes in density due to an increase in temperature and the number of CH2 groups in the long alkyl chains of cations are determined predominantly by changes in the free volume of the 'ionic' regions, while 'aliphatic' regions are already highly compressed by van der Waals forces, which results in only infinitesimal changes in their free volumes with temperature.

12345 1 - 50 of 210
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf