Ändra sökning
Avgränsa sökresultatet
123 101 - 134 av 134
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 101.
    Taher, Mamoun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Orthoborate Ionic Liquids for Lubricated Interfaces2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The lifespan and efficiency of various types of machinery is often limited by the performance of its lubricated interfaces, which are formed by two interacting surfaces and a lubricant that separates the surfaces to decrease friction and wear. There is a constant quest for more efficient lubricants capable of lubricating non-ferrous surfaces. Ionic liquids (ILs) possess many unusual physicochemical properties compared to molecular liquids including, but not limited to, high polarity, high conductivity, high thermal stability, and a wide liquid range. Such properties are essential for formulating lubricants for interfaces in challenging applications such as in aerospace and wind turbines. Some ILs have recently shown promising performance in lubricating lightweight non-ferrous alloys and hard coatings, among other materials. However, most of the widely studied ILs contain anions with fluorine, such as [BF4]- and [PF6]-, and are prone to hydrolysis, releasing toxic HF, among other corrosive products. In this work, we designed, synthesized, and thoroughly characterized a number of hydrophobic ILs based on halogen-free and hydrolytically-stable orthoborate anions and different classes of cations such as pyrrolidinium and imidazolium. The potential of these ILs to efficiently lubricate ferrous and non-ferrous interfaces was investigated.The work was planned and carried out through the following steps: Design, synthesis and purification of novel, halogen-free, boron-based ionic liquids (hf-BILs). Physicochemical characterization of the synthesized compounds by liquid-state (1H, 13C, and 11B) and solid-state (13C and 11B) nuclear magnetic resonance (NMR) spectroscopy, Karl Fischer titration, mass spectroscopy, elemental analysis, inductively coupled plasma mass spectrometry (ICP-MS), thermal analysis (TGA, DSC), powder X-ray diffraction, density and rheological measurements. Evaluation of their lubrication performance using ball-on-disc tribometers. Analysis of the lubricated surfaces using Scanning Electron Microscopy coupled with X-ray Energy Dispersive Spectroscopy (SEM/EDS) and a stylus profilometer.A detailed description of the results obtained for selected classes of ILs is given below: I. Nine novel ILs of N-alkyl-N-methylpyrrolidinium bis(salicylato)borate ([CnC1Pyrr][BScB]) were synthesized and physicochemically characterized. They are solids at room temperature and some of them behave as plastic crystals. Some of these compounds were tested as neat lubricants in steel-steel interfaces at 423 K, i.e., above their melting points. The tested compounds showed significantly better anti-wear and friction-reducing performance compared with 5W40 engine oil.II. Eight novel, room-temperature N-alkyl-N-methylpyrrolidinium bis(mandelato)borate ([CnC1Pyrr][BMB]) ILs were synthesized and physicochemically characterized. Their lubrication potential as 3 wt% additives in polyethylene glycol (PEG) was evaluated in steel-steel interfaces at room temperature. Considerably better anti-wear and friction-reducing properties were achieved when compared with neat PEG and 5W40 engine oil.III. Three novel, room-temperature 1-alkyl-3-methyl-imidazolium bis(mandelato)borate ([CnC1Im][BMB]) ILs were synthesized and physicochemically characterized.IV. A room-temperature trihexyltetradecylphosphonium bis(oxalato)borate [P6,6,6,14][BOB] IL, was evaluated as a neat lubricant for alumina-steel and sapphire-steel interfaces at room temperature. [P6,6,6,14][BOB] provided lower friction and wear compared with 5W40 engine oil.

  • 102.
    Trublet, Mylene
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Outline of Titanium (IV) based H2PO4 Ion-exchangers: Kinetics and Sorption models2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Decontamination of industrially polluted waters has been enclosed in REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) since 2007, when it entered into force in the European Union, which emphasized the need to search for more effective sorbents. Many studies on inorganic ion-exchangers have been carried out due to the scientific interest towards their high mechanical and thermal stabilities, high resistance to oxidation and high sorption capacity regarding transition and radioactive metal ions. Titanium phosphates (TiP) in particular, have revealed very good cation-exchange properties in relation to different transition metal ions in aqueous solutions. It has been demonstrated that their physicochemical properties as well as their structural characteristics can be altered by carefully choosing the conditions of synthesis: the temperature, acidity, Ti(IV) speciation in solution and reaction time. Since the ‘classical’ crystalline TiP ionites have been divided into two main groups: alfa type; α-TiP [α-Ti(HPO4)2•H2O] and gamma type; γ-TiP [Ti(H2PO4)(PO4)•H2O] with different functional groups (–H2PO4, –HPO4 and –PO4) present, the researchers have focused on synthesis of various metastable TiP with different functional properties. In this work, three different synthetic routes for TiP ion-exchangers were explored in order to obtain a sorbent composed solely of –H2PO4 exchange units. The ─H2PO4 groups were expected to considerably increase the pH working range of the sorbents and to nearly double the theoretical exchange capacity of TiP ion-exchangers containing mostly –HPO4 functional groups. Among the synthesized ion-exchangers (TiP1, TiP2 and TiP3), TiP1 has shown very good sorption characteristics and therefore, most of the studies were performed on it. TiP1 was synthesized at mild thermal conditions using cobalt(II) ions as a modifying agent and HCl-washes as post-synthetic treatments. This sorbent was characterized by different spectroscopic techniques and its chemical formula was established to be: TiO(OH)(H2PO4)•H2O. The sorption capacity of TiP1, estimated about 4.8 meq.g-1, is higher than the reported exchange capacity for various amorphous TiP. The sorption characteristics of TiP1 towards divalent ions such as Cu2+, Zn2+, Ni2+, Mn2+ and Co2+, were investigated in this work. The results of the sorption experiments (in the 1-20 mmol.L-1 range) were fitted to the Langmuir and Temkin models with the latter one being somewhat preferred for most of the metal ions studied. This indicates that interactions between adsorbed molecules cannot be neglected. It was also found that the kinetics of the ion-exchange process was very fast and the equilibrium was reached within 10 minutes. The kinetic data were modeled using the pseudo-second order reaction rate and the obtained curves were consistent with chemisorption being the rate limiting step of the reactions. The selectivity order of the metal ions studied towards TiP1 here was found to be: Cu2+ > Zn2+ > Mn2+ > Co2+ > Ni2+. The TiP1 sorbent has also shown to be a very good cation-exchanger when batch experiments were performed using heavy metals polluted waters from closed mines, supplied by Boliden AB. These studies delineated that TiP1 has displayed exclusive sorption capacities and imminent ion-exchange kinetics. It has been distinctly shown that a modest change in the synthesis could facilitate the fabrication of titanium phosphate ion-exchangers with improved and versatile sorption properties.

  • 103.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Azancheev, Nail
    Kazan (Volga Region) Federal University, Kazan.
    Taher, Mamoun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rabét, Pauline
    Department of Organic Chemistry, School of Chemistry, Manchester University.
    Glavatskih, Sergei
    System and Component Design, KTH, Royal Institute of Technology , Machine Design, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden, Department of Physics, Warwick University, Coventry, Department of Mechanical Construction and Production, Ghent University.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Self-diffusion and interactions in mixtures of imidazolium bis(mandelato)borate ionic liquids with polyethylene glycol: 1H NMR study2015Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 53, nr 7, s. 493-497Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 104.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Fayzullina, Adeliya R.
    Chemistry Institute, Kazan Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Karataeva, Farida Kh.
    Alexander Butlerov Institute of Chemistry, Kazan Federal University, Chemistry Institute, Kazan Federal University.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of fibrinopeptide B in water solution with DPC micelles by NMR spectroscopy2015Ingår i: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1102, s. 91-94Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 105.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Afonin, Sergei
    Karlsruhe Institute of Technology.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial Structures of PAP(262–270) and PAP(274–284), Two Selected Fragments of PAP(248–286), an Enhancer of HIV Infectivity2015Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 46, nr 7, s. 757-769Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 106.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 behaviour2015Ingår i: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 149, s. 881-888Artikel i tidskrift (Refereegranskat)
    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

  • 107.
    Ruyter-Hooley, Maika
    et al.
    La Trobe University.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Johnson, Bruce B.
    La Trobe University.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Angove, Michael J.
    La Trobe University.
    Surface complexation modeling of inositol hexaphosphate sorption onto gibbsite2015Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 440, s. 282-291Artikel i tidskrift (Refereegranskat)
    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:

  • 108.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 Protofibrils2014Ingår i: Angewandte Chemie, ISSN 0044-8249, E-ISSN 1521-3757, Vol. 126, nr 47, s. 12970-12974Artikel i tidskrift (Refereegranskat)
    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.

  • 109.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 Protofibrils2014Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 53, nr 47, s. 12756-12760Artikel i tidskrift (Refereegranskat)
    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.

  • 110.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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) coatings2014Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 11, s. 8353-8362Artikel i tidskrift (Refereegranskat)
    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

  • 111.
    Wang, Yong-Lei
    et al.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Glavatskih, Sergei
    System and Component Design, KTH, Royal Institute of Technology.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Laaksonen, Aatto
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Atomistic insight into orthoborate-based ionic liquids: force field development and evaluation2014Ingår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, nr 29, s. 8711-8723Artikel i tidskrift (Refereegranskat)
    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.

  • 112.
    Gowda, Vasantha
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Combined experimental and theoretical studies of dithiocarbamate complexes of yttrium, lanthanum and bismuth2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Metal-dithiocarbamate complexes find wide-ranging applications in nanomaterial and metalseparation science, and have potential use as chemotherapeutic, pesticides, and as additives tolubricants. A highly versatile dialkyldithiocarbamate (R2NCS2–) ligand can form stablecomplexes with all the transition elements and also the majority of main group, lanthanide andactinide elements. Here we present structural investigations of the molecular and electronicstructures of dialkyldithiocarbamate complexes with yttrium(III), lanthanum(III), andbismuth(III) of molecular formula [Y{S2CN(C2H5)2}3PHEN], [La{S2CN(C2H5)2}3PHEN], and[Bi2{S2CN-n(C4H9)2}6] (where PHEN=1,10-Phenanthroline) . The experimental solid-state 13Cand 15N cross polarization magic-angle-spinning (CP-MAS) NMR results are reported for allthese three complexes. We also report new single-crystal X-ray structures of heterolepticyttrium, lanthanum, and homoleptic bismuth dialkyldithiocarbamate complexes. Thecomparative analysis of powder XRD patterns and solid-state 13C and 15N CP-MAS spectra ofpolycrystalline yttrium(III) and lanthanum(III) diethyldithiocarbamato-phenanthrolinecomplexes shows the presence of significant structural differences. The diethyldithiocarbamatophenanthrolinecomplex of yttrium has a very similar structural type to a previously reported Xraydiffraction structure for [Nd{S2CN(C2H5)2}3PHEN] whereas, the crystal structure of[La{S2CN(C2H5)2}3PHEN] is considerably more complex. Our NMR and single-crystal X-raydiffraction results suggested polymorphism for bismuth di-n-butyldithiocarbamate complex.Finally, the experimental NMR results are complemented by chemical shifts obtained usingquantum chemical methods and verified the spectral assignments. Overall, our workdemonstrates how different experimental and theoretical methods can be combined that canafford insights into the solid-state structure and bonding environments of metal complexes.

  • 113.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 Insertion2014Ingår i: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 106, nr 10, s. 2134-2142Artikel i tidskrift (Refereegranskat)
    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.

  • 114.
    Patra, Anuttam
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rao, Hanumantha
    Fredriksson, Andreas
    LKAB.
    Bordes, Romain
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Holmberg, Krister
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Design and development of novel mineral-specific collectors for flotation2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Almost all of the flotation reagents used today were discovered by continued application of empirical methods and/or trial and error experimentation. Moreover, with the metal-ion specific approach used so far, it is difficult to separate the minerals containing the same constituent metal ion. A critical assessment of molecular recognition processes involved in biomineralization suggested the possibility of using reagents which are surface specific. The concept that the molecules consisting of two or more functional groups having appropriate spacing between those so as to achieve structural/stereochemical compatibility during interaction with the mineral surface exhibit structure-specificity is thought to be extended to the design of specific collectors in flotation processes. In the present study, for the first time, a rational design of surface active molecules, and thereby the recognition of crystal faces (of minerals) by these molecules through structural and stereochemical matching is being utilized successfully to selectively float various minerals. For this purpose, carboxylate-based collectors (for mineral specific flotation of calcium minerals) as well as xanthate-based collectors (for mineral specific flotation of sulphide minerals) with a fixed alkyl chain length but having two functional groups with varying geometrical distances (separated by a spacer of one, two and three carbon atoms) between them have been synthesized. In this article, we have discussed the design, synthesis, purification of these novel mineral specific collectors as well as their important solution parameters in relation to flotation processes.

  • 115.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Kotenkov, Sergey A.
    Kazan (Volga Region) Federal University, Kazan.
    Munavirov, Bulat
    Kazan (Volga Region) Federal University, Kazan.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Effect of Curcumin on Lateral Diffusion of Phosphatidylcholines in Saturated and Unsaturated Bilayers2014Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, nr 35, s. 10686-10690Artikel i tidskrift (Refereegranskat)
    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 %.

  • 116.
    Taher, Mamoun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Glavatskih, Sergei
    Machine Design, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Halogen-free ionic liquids in lubrication2014Konferensbidrag (Refereegranskat)
    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.

  • 117.
    Taher, Mamoun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Baets, Patrick De
    Department of Mechanical Construction and Production, Ghent University.
    Glavatskih, Sergei
    Department of Mechanical Construction and Production, Ghent University.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Halogen-free pyrrolidinium bis(mandelato)borate ionic liquids: some physicochemical properties and lubrication performance as additives to polyethylene glycol2014Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, nr 58, s. 30617-30623Artikel i tidskrift (Refereegranskat)
    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.

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

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

  • 119.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rao, Hanumantha
    Bordes, Romain
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Holmberg, Krister
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Fredriksson, Andreas
    LKAB.
    Molecular recognition in mineral flotation: Selectivity in apatite-calcite system2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying length between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant with the same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite and calcite mineral surfaces was studied using Hallimond tube flotation, FTIR and ζ potential measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much more selective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ζ potential and infra-red spectroscopy data.

  • 120.
    Arkhipov, Victor P.
    et al.
    Kazan National Research Technological University.
    Idiyatullin, Zamil Sh.
    Kazan National Research Technological University.
    Gnezdilov, Oleg I.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Petrova, Ekaterina V.
    Kazan National Research Technological University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Molecular self-diffusion and micellar structure in the aqueous solutions of AF9-10 ethoxylated isononylphenol near a cloud point2014Ingår i: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 24, nr 5, s. 266-268Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 121.
    Usachev, Konstatin S.
    et al.
    Kazan (Volga Region) Federal University, Kazan.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Khairutdinov, B.I.
    Kazan (Volga Region) Federal University, Kazan.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 micelles2014Ingår i: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1076, s. 518-523Artikel i tidskrift (Refereegranskat)
    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.

  • 122.
    Munavirov, Bulat V.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rudakova, Maya A.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Polyacrylic Acid Modifies Local and Lateral Mobilities in Lipid Membranes2014Ingår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 35, nr 6, s. 848-858Artikel i tidskrift (Refereegranskat)
    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.

  • 123.
    Korneeva, E V
    et al.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Rodina, T A
    Amur State University, Blagoveshchensk, Russian Federation.
    Ivanov, A V
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Gerasimenko, A V
    Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 690022, Vladivostok.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Polymeric Gold(I) Diisobutyl Dithiophosphate, [Au2{S2P(O-iso-C4H9)2}2]n: Synthesis, Supramolecular Self-Organisation (a Role of Aurophilic Interaction), 13C and 31P MAS NMR Spectroscopy, and Thermal Behavior2014Ingår i: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 40, nr 10, s. 748-756Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new polymeric gold(I) diisobutyl dithiophosphate (Dtph), [Au2{S2P(O-iso-C4H9)2}2] n (I), was preparatively obtained and characterized by 13C and 31P MAS NMR spectroscopy and X-ray diffraction (CIF file CCDC no. 977818). Diagrams of the χ2 statistic were constructed from the complete 31P MAS NMR spectra and used to calculate the 31P chemical shift anisotropy (δ aniso = δ zz − δ iso ) and the asymmetry parameter η = (δ yy − δ xx )/(δ zz − δ iso ). The main structural unit of complex I is the noncentrosymmetric dinuclear molecule [Au2{S2P(O-iso-C4H9)2}2], in which the gold atoms are linked by two bridging ligands Dtph. The central cyclic structural fragment of the dimer [Au2S4P2] is additionally stabilized by the intramolecular aurophilic interaction Au⋯Au. Further supramolecular self-organization of the complex involves intermolecular aurophilic bonds Au⋯Au that serve to unite adjacent dinuclear molecules [Au2{S2P(O-iso-C4H9)2}2] with different spatial orientations into the polymer chains ([Au2{S2P(O-iso-C4H9)2}2]) n . The thermal behavior of complex I was examined by synchronous thermal analysis under argon. The character of the thermolysis of the complex to reduced metallic gold as a final product was determined.

  • 124.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Karataeva, Farida Kh.
    Alexander Butlerov Institute of Chemistry, Kazan Federal University.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of oligopeptide PAP(248-261), the N-terminal fragment of the HIV enhancer prostatic acid phosphatase peptide PAP(248-286), in aqueous and SDS micelle solutions2014Ingår i: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1070, s. 38-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 125.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 isomerism2014Ingår i: Doklady. Physical chemistry, ISSN 0012-5016, E-ISSN 1608-3121, Vol. 454, nr 1, s. 16-20Artikel i tidskrift (Refereegranskat)
  • 126.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Taher, Mamoun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Glavatskih, Sergei
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    The effect of the cation alkyl chain length on density and diffusion in dialkylpyrrolidinium bis(mandelato)borate ionic liquids2014Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, nr 48, s. 26798-26805Artikel i tidskrift (Refereegranskat)
    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.

  • 127.
    Taher, Mamoun
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Glavatskih, Sergei
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Halogen free boron-based ionic liquids as novel lubricants2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Most of the modern lubricants and lubricant additives have been designed and optimized for ferrous materials. A growing trend towardswider use of lightweight and wear resistant non-ferrous materials calls for new efficient and environmentally friendly lubricants.In this study, halogen free boron based ionic liquids (hf-BILs) were designed, synthesized and tribologically tested for ferrous and non-ferrous materials.

  • 128.
    Gowda, Vasantha
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Lantto, Perttu
    University of Oulu.
    Modelling and structrual optimizations of rare earth coordination: First principles calculations2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    An approximate 3D structure for the yttrium diethyldithiocarbamato-phenanthroline complex 1, obtained by manually replacing the Nd3+ ion with Y3+ion of the reported crystal structure for neodymium diethyldithiocarbamato-phenanthroline complex 2 followed by DFT geometry optimization using periodic boundary conditions with dispersion corrected functional, has been compared with DFT optimized structure for 1. The quality of the method is discussed by comparing predicted PXRD pattern, high resolution solid state 13C and 15N CP/MAS NMR data and calculated chemical shift tensor eigenvalues for optimized structures for 1 and 2. We have observed an excellent agreement between the ‘modeled’ and experimental structures. Finally, to take into account the relativistic effects on NMR shielding calculations, we have employed the zeroth-order regular approximation (ZORA) formalism using Slater-type orbital (STO) basis sets implemented in Amsterdam Density Functional (ADF) package. The present approach can be further extended to study other complexes of rare earth metals in general, particularly those having similar crystal structure.

  • 129.
    Gowda, Vasantha
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Project: Solid-State NMR and DFT calculations on rare earth metal complexes2013Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 130.
    Yang, Xiaofang
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Interaction of magnetite with soluble silicates and bentonite: implications for wet agglomeration of magnetite concentrate2011Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Iron ore green pellets are produced by agglomeration of moist magnetite concentrates. The quality of green pellets is essential for the transportability and metallurgical benefits of the final product. The agglomeration behavior of magnetite concentrate particles is strongly influenced by its surface properties which are affected by the interactions with flotation reagents (i.e. water glass and collector) and species in process water. However, the mechanisms of these interactions and the influence on the following agglomeration process are still not completely understood. The present work has been focused on the interaction of magnetite with water glass (sodium silicate) and bentonite clay (silicate mineral) aiming for better fundamental knowledge of the magnetite surface properties in order to improve the agglomeration behavior of the magnetite concentrate. Water glass is used as a dispersing or depressing agent in flotation of magnetite. The former function is to improve the separation of mineral particles in the pulp, while the latter function is to protect the magnetite surfaces from attachment of the collector which is known to cause problems in the subsequent agglomeration process. Sodium activated bentonite clay is commonly used as an external binder in iron ore agglomeration owing to its swelling properties. The particle interaction between magnetite and bentonite platelets, which is expected to be affected by the surface properties of magnetite, is of importance for the wet and dry strength of the pellets. Sorption mechanisms of sodium silicate onto the magnetite surface at the molecular scale were studied at various pH and silicate concentrations using in-situ ATR-FTIR spectroscopy. Silicate concentration, pH, and conditioning time are the most important factors for silicate sorption and speciation at the surface of magnetite. A maximum sorption was observed in the pH range 8.5 - 9.5. Oligomeric or polymeric silicate species are formed and dominate at high surface loading of silicate. These oligomeric or polymerized species have stronger affinity for the magnetite as compared to monomeric species, resulting in a slower and less extent of desorption and implying a higher depressing efficiency in flotation. Sodium silicate makes the magnetite surface more negatively charged, while adsorbed calcium ions on the surface compensate this negative surface charge. Calcium ions promote the oligomerization of silicate on the surface of magnetite at high pH (pH > 10) possibly due to the increased local silicate concentration by additional sorption of silicate on adsorbed calcium at the surface. The competitive sorption between sodium silicate and collector (sodium oleate) for the magnetite surface was studied using the in situ ATR-FTIR technique. It was confirmed that oleate could still be adsorbed onto a sodium silicate modified magnetite surface but the amount of adsorbed oleate decreased with increasing concentration of silicate (0.1 - 5 mmol•L-1). This depression effect became much more significant when the concentration of sodium silicate was higher than 0.4 mmol•L-1 above which more dimers or oligomeric silicate species were formed at the magnetite surface. However, when the magnetite surface was pre-treated firstly with sodium oleate, the addition of sodium silicate only slightly reduced the adsorption of oleate. Meanwhile, the sorption of silicate anions was depressed and resulted in a lower degree of oligomerization or polymerization at high silicate dosage. Sessile drop method and Wilhelmy method were used to measure the water contact angle of synthesized magnetite, and Washburn method was used for contact angle measurements of magnetite concentrate. The synthesized magnetite has lower contact angle compared to mineral particles. Nevertheless, similar tendency of changes in wettability upon interaction with calcium, sodium silicate and collector was observed for synthesized magnetite and magnetite concentrate. Sorption of calcium and silicate increased the wettability of the surface, while adsorption of collector made the surface more hydrophobic. Further exposure of the collector modified magnetite surface to sodium silicate could restore the surface wettability. Therefore, an interesting implication for magnetite flotation and agglomeration is that the decreased hydrophilicity of magnetite by attachment of collector could be improved by further chemical conditioning with sodium silicate (water glass). The interaction of bentonite with magnetite was investigated by means of settling of bentonite platelets onto a layer of magnetite nano-particles. The magnetite layer was deposited on a horizontal ZnSe crystal to be able to examine the orientation of the platelets by polarized ATR-FTIR. The measured dichroic ratio of the bentonite platelets decreased with time in wet film and approached a minimum value in the dry bentonite film regardless of the pH of the bentonite suspension. This tendency is in good agreement with the results observed for settling on bare crystal, indicating a more ordered structure of platelets upon evaporation of water. The bentonite platelets in dry film were evidently tending to orient with their basal plane surfaces to the magnetite layer, whilst wet films adopted a much more disordered structure. Similarly, a rather disordered wet bentonite film was formed on the calcium and sodium silicate modified magnetite layer. These bentonite platelets became more ordered when the wet film was dried.

  • 131.
    Roonasi, Payman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Sorption reactions between ionic species and magnetite in aqueous solution2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The surface chemistry of inorganic materials is of great significance in a number of industrially important processes such as separation of ore by flotation, catalysis, water purification, leaching, as well as in the formulation of some pharmaceutical preparations. This thesis deals with magnetite and its sorption properties. Especially it was focused on the sorption of ions present in the process water and possibly affecting the balling properties of the magnetite concentrate in the pelletizing process. It is well-known that these properties become deteriorated if the magnetite surface becomes less hydrophilic, which motivated the use of an amphiphilic adsorbate (sodium oleate) in this study.The magnetite nano-particles were synthesized and subsequently characterized by X-ray, electron microscopy, and infrared spectroscopy. The mechanisms of magnetite formation from co-precipitation of Fe (II) and Fe (III) as well as oxidation of ferrous hydroxide were evaluated using iron isotope fractionation measurements (Paper I).Since magnetite pellets are heated during the sintering process and also may contain small amounts of the hydrophobic collector used in the flotation process, it was interesting to follow what happened with a model collector such as sodium oleate upon heating the magnetite/oleate system. This was studied using a combination of thermal analysis and FTIR spectroscopy. It was found that the oleate molecules were bonded to iron atoms by predominantly a bidentate mononuclear complex and formed essentially a single layer with a distance between the oleate molecules of ~36 Å2. Thermogravimetric analysis showed indicated double bond cleavage that yielded products enriched in oxygen and also capable of forming hydrogen bonds (Paper II).To study how the magnetite surface might be modified caused by process water, the magnetite nano-particles were evenly distributed over an internal reflection element and this combination was used to study the adsorption of ions present in the process water in-situ. The ionic system included the model collector (oleate) in stead of the collector used in practise (Atrac) to separate apatite from magnetite. Among ions in the process water, the adsorption properties of sulphate, silicate, and carbonate were studied as well as the effect of calcium ions on the adsorption properties and the competition between silicate and oleate for the magnetite surface. Paper III focused on the effect of Ca (II) on the adsorption of sulphate and it could be concluded that this effect was of minor importance. On the other hand, calcium ions in solution had a large effect on the adsorption of carbonate ions onto magnetite (Paper VII). During the flotation process, silicate is added to the pulp in order to disperse the magnetite particles and make the reverse flotation of apatite from magnetite more efficient. Accordingly, the adsorption of silicate onto magnetite as well as maghemite was investigated as a function of pH (Papers IV and V). Finally, the kinetics of oleate adsorption onto magnetite and competition between sodium oleate and sodium silicate for the magnetite surface was studied. Of particular interest was to which extent oleate could possibly be substituted for silicate and vice versa. These studies are elaborated in Paper VI.

  • 132.
    Marivel, Samipillai
    et al.
    Solid State & Supramolecular Structural Chemistry Unit, Division of Organic Chemistry.
    Shimpi, Manishkumar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Pedireddi, V.R.
    Solid State & Supramolecular Structural Chemistry Unit, Division of Organic Chemistry.
    Novel Supramolecular Assemblies of Coordination Polymers of Zn(II) and Bis(4-nitrophenyl)phosphoric Acid with Some Aza-Donor Compounds2007Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 7, nr 9, s. 1791-1796Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Supramolecular assemblies of coordination polymers of Zn(II) and bis(4-nitrophenyl)phosphoric acid, BNPP, with aza-donor compounds, 4,4¢-bipyridine (bpy), 1,2-bis(4-pyridyl)ethane (bpyea), 1,2-bis(4-pyridyl)ethene (bpyee), and 1,3-bis(4-pyridyl)-propane (bpypa), have been reported. All the compounds are quite similar in the three-dimensional packing, irrespective of the varied dimensions of aza-donor molecules. All four compounds were synthesized by treating BNPP with corresponding aza-donor molecules in the presence of MeOH and water as the solvents. The structures were characterized by single-crystal X-ray diffraction.

  • 133.
    Shimpi, Manishkumar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Seethalekshmi, Nanappan
    Solid State & Supramolecular Structural Chemistry Unit, Division of Organic Chemistry, National Chemical Laboratory, Pune.
    Pedireddi, V.R.
    Solid State & Supramolecular Structural Chemistry Unit, Division of Organic Chemistry, National Chemical Laboratory, Pune.
    Supramolecular architecture in some 4-halophenylboronic acids2007Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 7, nr 10, s. 1958-1963Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Crystal structures of 4-chloro- and 4-bromophenylboronic acids (1 and 2) and hydrates of 2 and 4-iodophenylboronic acid in two different forms (2a, 3a, and 3b), which were characterized by single-crystal X-ray diffraction methods, are reported. In structures I and 2, -B(OH)2 forms a syn-anti conformation, but it exists in syn-syn as well as anti-anti conformations in the hydrated structures 2a, 3a, and 3b. In all the structures, the molecules are held together by O-H center dot center dot center dot O interactions formed by -B(OH)2 groups. The C-H center dot center dot center dot X (X = Cl, Br, and I) interactions play an important role in crystal packing. In 2, Br center dot center dot center dot Br interactions are also observed. Interestingly, all the three hydrates form similar types of three-dimensional structures with the formation of channels, which are occupied by water molecules. The two hydrates of 4-iodophenylboronic acid (3a and 3b) are distinguishable on the basis of O center dot center dot center dot O short contacts, with an identical host lattice of the boronic acid.

  • 134.
    Pedireddi, V.R.
    et al.
    Solid State and Supramolecular Structural Chemistry Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, School of Basic Sciences, Indian Institute of Technology Bhubaneswar.
    Shimpi, Manishkumar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Yakhmi, J V
    Bhabha Atomic Research Centre, Trombay, Mumbai.
    Room-temperature ionic liquids: For a difference in the supramolecular synthesis2006Ingår i: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 241, nr 1, s. 83-87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cu(I) and Ni(II) coordination polymers with 4,4'-bipyridine and 2,2'bipyridine, respectively, that have been synthesized from an ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate) gave different coordination environment and supramolecular networks than the corresponding synthesis from the other solvents. The resultant complexes were characterized by single crystal x-ray diffraction methods.

123 101 - 134 av 134
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf