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  • 1.
    Korneeva, E.V.
    et al.
    Institute of Geology and Nature Management, Far-Eastern Branch of the Russian Academy of Sciences, Blagoveschensk, Russian Federation.
    Smolentsev, A. I.
    Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation. Novosibirsk State University, Novosibirsk, Russian Federation.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. University of Warwick, Coventry, United Kingdom.
    Ivanov, A. V.
    Institute of Geology and Nature Management, Far-Eastern Branch of the Russian Academy of Sciences, Blagoveschensk, Russian Federation.
    Binding of gold(iii) with silver(i) dipropyldithiocarbamate: supramolecular self-assembly (role of secondary Au…S and Ag…S bonds) and thermal behavior of the ionic-polymer complex ([Au(S2CNPr2)2][AgCl2])n2019Ingår i: Russian chemical bulletin, ISSN 1066-5285, E-ISSN 1573-9171, Vol. 68, nr 1, s. 40-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The double ionic-polymer complex ([Au(S2CNPr2)2][AgCl2])n (1) was prepared as an individual fixation form of gold(III) from NaCl solutions with silver(I) dipropyldithiocarbamate and was characterized by single-crystal X-ray diffraction and 13C magic-angle spinning (MAS) NMR spectroscopy. The structure of 1 comprises two nonequivalent centrosymmetric complex cations [Au(S2CNPr2)2]+ (A and B) and the discrete linear anion [AgCl2]. Gold(III) cations are linked by pairs of unsymmetrical secondary Au…S bonds to form linear supramolecular chains (…A…B…)n. Neighboring cations are additionally linked by [AgCl2] anions via secondary Ag…S and Cl…S bonds, the anions being involved in the overall stabilization of the supramolecular structure. The cation–anion interactions lead to a distortion of the linear configuration of the [AgCl2] anion. The character of thermolysis of 1 accompanied by quantitative regeneration of bound Au and Ag was established by simultaneous thermal analysis.

  • 2.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Russia.
    Bhattacharyya, Shubhankar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    CO2 absorption and ion mobility in aqueous choline-based ionic liquids2019Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 276, s. 748-752Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    CO2 absorption and ion mobility are investigated in a series of 50/50 wt% aqueous solutions of choline-based ionic liquids with different cations and anions: [N1,1,4,2OH][Threo], [N1,1,5,2OH][Threo], [N1,1,6,2OH][Threo], [N1,1,5,2OH][β-ala] and [N1,1,5,2OH][Tau]. The process of CO2 absorption was completed in an hour reaching maximum of absorption capacity 0.07–0.10 wt% to ionic liquid (by 0.4–0.6 molar ratios). A rapid CO2 absorption is observed by the formation of solid product as a result of reaction between CO2 molecule and the ionic liquid. Diffusion coefficients of the cation and anion in the mixture are comparable while the diffusivity of water molecules is found to be quite different from the ions. In the process of CO2 absorption, an increase in the diffusivity of ions is observed due to the precipitation of solid products and depletion of ions contents in the liquid phase of the system. 13C NMR measurements of diffusivity of CO2 enriched with 13C isotope showed that a part of the absorbed CO2 remained in the liquid phase being physically and chemically bound to ions. The ionic liquid is re-cycled by evaporating water and releasing CO2 molecules using vacuum and temperature.

  • 3.
    Trublet, Mylene
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Scukins, Edvards
    Aeronautics, Department of Flight Data and Navigation, SAAB, Linköping, Sweden.
    Carabante, Ivan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rusanova-Naydenova, Daniela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Competitive Sorption of Metal Ions on Titanium Phosphate Sorbent(TiP1) in Fixed-Bed Columns: A Closed-Mine Waters Study2019Ingår i: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 7, nr 9, s. 8145-8154Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sorptionfixed-bed column experiments were performed using atitanium phosphate ion-exchanger composed of−H2PO4units [TiO(OH)(H2PO4)·H2O]. Model mine water containingfive divalent metal ions (Cu2+,Zn2+,Mn2+,Ni2+,and Co2+) and a few closed-mine water samples were treated to evaluate the sorptionpreference of the material. For thefirst time, dynamic ion-exchange capacities(estimated to be between 3.2 and 4.2 mequiv g−1) and static ion-exchange uptakes(calculated to be between 3.1 and 3.5 mequiv g−1) were obtained for the same TiP1sorbent and data were discussed in terms of sorption behavior. It was found thatsorption processes on TiP1 in model and closed-mine waters during a columnexperiment could be accurately predicted from the corresponding batch experiment(including the sorbent’s capacities in different types of waters). A competitivesorption phenomenon in favor of Cu2+on TiP1 was established for all cases, pointingtoward the possibility of isolating pure copper concentrate from closed-mine waters.The relatively high amounts of calcium and magnesium ions present in mine waters did not appear to considerably affect theselectivity of TiP1 material. Exploratory experiments for sorbent regeneration and desorption using a low concentration of nitricacid were demonstrated.

  • 4.
    Kotenkov, Sergey A.
    et al.
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Gnezdilov, Oleg I.
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Khaliullina, Aliya V.
    Institute of Physics, Kazan Federal University, Kazan, Russia;Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Gimatdinov, Roustam S.
    Kazan State Medical University, Kazan, Russia.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russia.
    Effect of Cholesterol and Curcumin on Ordering of DMPC Bilayers2019Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 50, nr 1-3, s. 511-520Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, we compared the effects of curcumin and cholesterol directly competing to insert into the DMPC lipid bilayer during bilayer formation from an initially non-ordered state. 2H and 14N nuclear magnetic resonance spectroscopy showed that curcumin is not embedded deep in the lipid bilayer and interacts mainly with the head group of the lipid. In a more complex system of DMPC/CHOL/CUR, curcumin amplifies the effect of cholesterol on the ordering of lipid acyl chains.

  • 5.
    Srivastava, Karnica
    et al.
    Physics Department, University of Lucknow, Lucknow, India.
    Shukla, Anuradha
    Physics Department, University of Lucknow, Lucknow, India.
    Karthick, T.
    Physics Department, University of Lucknow, Lucknow, India;Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Prague, Czech Republic.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Tandon, Poonam
    Physics Department, University of Lucknow, Lucknow, India.
    Sinha, Kirti
    Physics Department, University of Lucknow, Lucknow, India.
    Shimpi, Manishkumar R.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Molecular structure, spectroscopic signature and reactivity analyses of paracetamol hydrochloride monohydrate salt using density functional theory calculations2019Ingår i: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 21, nr 5, s. 857-865Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to understand the role of the intermolecular hydrogen bond interactions present in paracetamol hydrochloride monohydrated salt. Paracetamol hydrochloride monohydrate salt (PRA-HCl) and paracetamol (form I) were investigated via vibrational (FT-IR and FT-Raman) spectroscopy and density functional theory (DFT) to gain insight into the hydrogen bond patterns present in these crystalline materials. Two different density functionals, wB97X-D and M062X, were used for the comparison of the results. The geometrical parameters of PRA-HCl and form I obtained using these functional were compared with the crystallographic data, which proved the existence of intra-molecular and intermolecular hydrogen bonds. The C10O2 group of form I forms an intramolecular hydrogen bond, while the O1–H18 group of PRA-HCl forms an intermolecular hydrogen bond with a chloride ion (Cl), resulting in the elongation of the bond length and shift to a lower wavenumber for the O1–H18 group. To examine the potency of hydrogen bonding, quantum theory of atoms in molecules (QTAIM) calculations were performed and the results suggested that O1–H18⋯Cl22 is a strong intermolecular hydrogen bond. The chemical reactivity parameters reveal that the PRA-HCl and PRA-OXA cocrystals are more reactive and softer (low HOMO–LUMO energy gap) in comparison to paracetamol (form I).

  • 6.
    Rohlmann, Patrick
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Munavirov, Bulat
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Furó, István
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rutland, Mark William
    KTH Royal Institute of Technology, Stockholm, Sweden. Surfaces, Processes and Formulation, RISE Research Institutes of Sweden, Stockholm, Sweden.
    Glavatskih, Sergei
    KTH Royal Institute of Technology, Stockholm, Sweden. Department of Electrical Energy, Metals, Mechanical Constructions and Systems, Ghent University, Ghent, Belgium.
    Non-halogenated Ionic Liquid Dramatically Enhances Tribological Performance of Biodegradable Oils2019Ingår i: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, artikel-id 98Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is demonstrated that a phosphonium orthoborate ionic liquid may serve as a wear reducing additive in biodegradable oils at steel-steel surfaces in the boundary lubrication regime. Tribological tests were performed in a ball-on-three plate configuration. A set of surface characterization techniques—SEM/EDS, FIB and white light interferometry were used to characterize surfaces following the tribotests and to observe the formation of any tribofilms. 11B NMR was used to follow changes in the composition of the ionic-liquid-oil blends and to identify boron-containing decomposition products after the tribotests. The ionic liquid reduces the wear of steel surfaces by up to 92% compared to the neat oil at 90°C; it is shown that the reduction in wear can be correlated with the formation of boron enriched patches in the boundary films.

  • 7.
    Butakov, Anatoly
    et al.
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk, Russian Federation.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Gimatdinov, Roustam
    Medical and Biological Physics, Kazan Medical University, Kazan, Russian Federation.
    Chernov, Vladimir
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk, Russian Federation.
    Peculiarities of NMR relaxation in micellar gels of Pluronic F-1272019Ingår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 40, nr 3, s. 403-407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 8.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry, UK.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Reactivity of CO2 with aqueous choline-based ionic liquids probed by solid-state NMR spectroscopy2019Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 286, artikel-id 110918Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 9.
    Patra, Anuttam
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Taner, Hasan Ali
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Mining Engineering, Selcuk University Konya Turkey.
    Bordes, R.
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg.
    Holmberg, K.
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Selective flotation of calcium minerals using double-headed collectors2019Ingår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 40, nr 8, s. 1205-1216Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A study was performed involving a series of double-headed carboxylate collectors with varying distance between the head groups (one, two or three carbon atoms). A collector with the same alkyl chain length but with only one carboxylate group was also included. All these were amino-acid based amphiphiles and the polar head group was connected to the hydrophobic tail via an amide linkage. Selective flotation recovery of different calcium minerals using these collectors was investigated. The double-headed collector with one carbon atom between the carboxylate groups was an apatite and fluorite specific reagent while the monocarboxylate surfactant showed high specificity for calcite. The flotation behavior of a simple conventional collector of the same alkyl chain length, a fatty acid salt, was also determined under identical flotation conditions in order to understand the effect of the amide group. Complementary experiments (ζ potential measurements, adsorption isotherm determinations) were also performed for these reagents. In order to shed light on the selectivity obtained with the dicarboxylate surfactants, the distances between the head groups were calculated and compared with the distances between neighboring calcium atoms on the surface of the minerals. It was found that the high degree of selectivity could be rationalized by perfect matching of these distances. To the best of our knowledge this is the first study where flotation selectivity in complex calcium mineral systems has been explained in terms of molecular recognition governing the interaction between the collector and the mineral surface.

  • 10.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russia.
    Gnezdilov, Oleg I.
    Kazan Federal University, Kazan, Russia. Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia.
    Luchkin, Alexander G.
    Kazan Federal University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Self-diffusion of ethylammonium nitrate ionic liquid confined between modified polar glasses2019Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 284, s. 366-371Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ethylammonium nitrate (EAN) ionic liquid confined between flat polar glass platesdemonstrates variable diffusivity that is sensitive to an external static magnetic field. Outside the magnetic field, diffusivity between the plates is higher than that in the bulk. However, after placing the system in a strong static magnetic field, the diffusivity gradually decreased. These processes occur during transformations between phases formed in EAN subjected to micrometer-size restrictions outside and within the magnetic field (Filippov et al., JMolLiq. [2018] 268, 49). In this study, we used samples of two types: (i) with roughened surface formed by treatment of the glass plates with aqueous solutions of hydrofluoric acid and (ii) with vacuum deposited TiO2 layers with a thickness of ca. 1 μm at glass-plate edges. Neither the surface modification of the glass plates, nor the TiO2 layers controlled thickness of EAN confined between glass-plates significantly changed the above-described effects, which have been observed in studies using untreated glass plates. Therefore, the range of systems with detected phase transformations in EAN and accompanying effects, such as accelerated diffusivity and change in diffusivity under the influence of a static magnetic field, was expanded to the systems with roughened surfaces and the systems with TiO2 layers controlled inter-plates distances. Results of experiments with roughened surfaces additionally suggested that the phase transformation of confined EAN in the external magnetic field is isotropic in nature rather than a phase transition from “layered to bulk” structures.

  • 11.
    Loseva, O.V.
    et al.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, Blagoveshchensk, Russian Federation.
    Rodina, T.A.
    Amur State University, Blagoveshchensk, Russian Federation.
    Ivanov, A.V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, Blagoveshchensk, Russian Federation.
    Smolentsev, A.I
    Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation. Novosibirsk State University, Novosibirsk, Russian Federation.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. The University of Warwick, Coventry, UK.
    Tetranuclear heteroleptic mercury(ii) complexes of the composition [Hg4(S2CNPr2)6(NO3)2] and [Hg4(S2CNPr2)4Cl4]: structural organization, principles of construction of supramolecular polymeric chains, and thermal behavior2019Ingår i: Russian chemical bulletin, ISSN 1066-5285, E-ISSN 1573-9171, Vol. 68, nr 4, s. 782-792Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New heteroleptic mercury(ii) complexes [Hg4(S2CNPr2)6(NO3)2] (1) and [Hg4(S2CNPr2)4Cl4] (2) were synthesized and characterized by single-crystal X-ray dif raction and 13C and 15N MAS NMR spectroscopy. In these complexes, the metal atoms are linked in pairs by bridging dipropyldithiocarbamate ligands (Pr2Dtc) to form tetranuclear cations and molecules. The further structural organization of compound 1 to the polymeric chains [Hg4(S2CNPr2)6(NO3)2]n occurs due to the linking of [Hg4(S2CNPr2)6]2+ cations by pairs of bridging nitrate groups. The formation of the supramolecular polymeric structure of 2 is determined by pairwise secondary Hg⋯Cl bonds between the cyclic [Hg4(S2CNPr2)4Cl4] molecules, in which the central eight-membered metallocycle [Hg4S4] adopts a distorted chair conformation. The thermal behavior of compounds 1 and 2 was studied by simultaneous thermal analysis.

  • 12.
    Mushtaq, Irrum
    et al.
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Akhter, Zareen
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium2019Ingår i: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, s. 1-10, artikel-id 518Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    PEGylated tetra(aniline) ABA triblock structure PEG-TANI-PEG (2) consisting of tetra(aniline) (TANI) and polyethylene glycol (PEG) was synthesized by coupling the tosylated-PEG to boc-protected NH2/NH2 TANI (1) through a simple nucleophilic substitution reaction. Deprotection of 2 resulted in a leucoemeraldine base state of TANI (2-LEB), which was oxidized to stable emeraldine base (2-EB) state. 2-EB was doped with 1 M HCl to emeraldine salt (2-ES) state. FTIR, 1H and 13C NMR and UV-Vis-NIR spectroscopy, and MS (ESI) was used for structural characterization. The synthesized triblock structure exhibited good electroactivity as confirmed by CV and UV-Vis-NIR spectroscopy. Self-assembling of the triblock structure in aqueous medium was assessed by DLS, TEM, and SEM. Spherical aggregates were observed with variable sizes depicting the effect of concentration and oxidation of 2-LEB. Further, the aggregates showed acid/base sensitivity as evaluated by doping and dedoping of 2-EB with 1 M HCl and 1 M NH4OH, respectively. Future applications in drug delivery and sensors are envisaged for such tunable self-assembled nanostructures in aqueous media.

  • 13.
    Loseva, O.V
    et al.
    Institute of Geology and Nature Management, Far-East Branch, Russian Academy of Sciences, Blagoveshchensk, Russia.
    Rodina, T.A
    Amur State University, Blagoveshchensk, Russia.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. University of Warwick, Coventry, United Kingdom.
    Ivanov, A.V
    Institute of Geology and Nature Management, Far-East Branch, Russian Academy of Sciences, Blagoveshchensk, Russia.
    Chemisorption Activity of Mercury(II) Cyclopentamethylenedithiocarbamate: Synthesis, Structure, and Thermal Behavior of the [Hg2{S2CN(CH2)5}4] and [Au3{S2CN(CH2)5}6][Au{S2CN(CH2)5}2][Hg2Cl6]2 Complexes2018Ingår i: Russian journal of general chemistry, ISSN 1070-3632, E-ISSN 1608-3350, Vol. 88, nr 12, s. 2540-2549Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dinuclear complex mercury(II) cyclopentamethylenedithiocarbamate (piperidine-1-carbodithioate) [Hg2{S2CN(CH2)5}4] was synthesized and its chemisorption activity toward a solution of AuCl3 in 2 M HCl was studied. The chemisorption of gold from the solution forms an ionic gold(III)‒mercury(II) dithiocarbamato-chlorido complex comprising three isomeric gold cations and an unsymmetrical hexachlorodimercurate anion. The structural organization and thermal behavior of the resulting compounds was studied.

  • 14.
    Ivanov, Alexander V.
    et al.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences .
    Gerasimenko, A.V.
    Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences.
    Egorova, I.V.
    Blagoveshchensk State Pedagogical University.
    Zaeva, A.S.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences.
    Novikova, E.V.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences.
    Rodionova, N.A.
    Blagoveshchensk State Pedagogical University.
    Gowda, V.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. University of Oulu.
    Antzutkin, O.N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Warwick University.
    Chemisorption Synthesis of the Ion-Polymeric Heteronuclear Gold(III)-Bismuth(III) Complex ([Au{S2CN(C3H7)2}2]3[Bi2Cl9])n Based on [Bi2{S2CN(C3H7)2}6]: 13C MAS NMR, Supramolecular Structure, and Thermal Behavior2018Ingår i: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 44, nr 8, s. 518-531Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chemisorption synthesis on the basis of the binuclear compound [Bi2{S2CN(C3H7)2}6] (I) and preparative isolation of the ion-polymeric heteronuclear gold(III)-bismuth(III) complex ([Au{S2CN(C3H7)2}2]3[Bi2Cl9])n (II) are carried out. Compounds I and II are characterized in comparison by IR spectroscopy and 13C CP-MAS NMR. According to the X-ray diffraction analysis data (CIF file CCDC no. 1407705), the cationic moiety of compound II exhibits an unusually complicated supramolecular structure including six isomeric noncentrosymmetric complex cations [Au{S2CN(C3H7)2}2]+ (hereinafter A-F) and two binuclear anions [Bi2Cl9]3- as conformers. The isomeric gold(III) cations perform various structural functions. Owing to pair secondary interactions Au···S, cations B, C, E, and F form centrosymmetric ([E···E], [F···F]) and noncentrosymmetric ([B···C]) binuclear aggregates [Au2{S2CN(C3H7)2}4]2+, whereas cations A and D are not involved in dimerization. The strongest secondary Au···S bonds are formed between the binuclear and mononuclear cations, resulting in the formation of supramolecular cation-cationic polymer chains of two types: (⋅⋅⋅A⋅⋅⋅[B⋅⋅⋅C]⋅⋅⋅A⋅⋅⋅[B⋅⋅⋅C]⋅⋅⋅)n and (D⋅⋅⋅[E⋅⋅⋅E]⋅⋅⋅D⋅⋅⋅[F⋅⋅⋅F]⋅⋅⋅])n. In both chains, the gold atoms of the binuclear cations are characterized by a distorted octahedral coordination [S6], whereas in the mononuclear cations the gold atoms retain the square environment [S4]. The cation-anionic interactions are provided by secondary bonds Cl⋅⋅⋅S involving the terminal chlorine atoms of isomeric [Bi2Cl9]3- and the sulfur atoms of the binuclear cations [Au2{S2CN(C3H7)2}4]2+. The character of the thermal behavior of compounds I and II is studied by simultaneous thermal analysis with the identification of intermediate and final products of the thermal transformations. The thermolysis of compound I at 193-320°C is accompanied by the formation of Bi2S3 with an impurity of reduced metallic bismuth particles. The final products of the thermal transformations of compound II are reduced elemental gold and Bi2O3, and the thermal transformation intermediates are BiCl3 and Bi2S3.

  • 15.
    Trublet, Mylene
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rusanova-Naydenova, Daniela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Complete Column Trials for Water Refinement Using Titanium(IV) Phosphate Sorbents2018Ingår i: ACS Sustainable Chemistry & Engineering, E-ISSN 2168-0485, Vol. 6, nr 5, s. 6157-6165Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A titanium phosphate sorbent with linked active units (LTP) is synthesized. XRD, 31P MAS NMR, and TGA techniques are used to disclose the relation between the ion-exchange units of −HPO4 (crystalline α-TiP) and of −H2PO4 (amorphous TiP1) type. The reported kinetics data of TiP1 sorbent in batch mode have been reprocessed according to the nonlinear approach in order to explore further the sorption mechanism. It was found that the data could be well described by the pseudo-second-order model in the case of Ni2+ ions. Consequently, fixed-bed column sorption experiments of Ni2+ ions on LTP were designed, and the effects of both the amount of nickel(II) ions in the feed solution and the flow rates on the sorption equilibrium were studied. The ion-exchange capacity is estimated to be 1.6 meq·g–1 during the first four cycles before decreasing to 1.2 meq·g–1 for cycles five and six. The experimental data were simulated following the Thomas model, and desorption experiments with HCl were performed. Observations show that regeneration and reutilization of the LTP ion-exchanger are possible through at least six cycles. It is revealed that the sorption performances in column conditions could be undoubtedly predicted from the corresponding batch sorption data.

  • 16.
    Trublet, Mylène
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rusanova-Naydenova, Daniela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg N
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, CV47AL, UK.
    Correction: Revisiting syntheses of Ti(IV)/H2PO4–HPO4functional ion-exchangers, properties and features2018Ingår i: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 42, nr 2, s. 1521-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Correction for ‘Revisiting syntheses of Ti(IV)/H2PO4–HPO4 functional ion-exchangers, properties and features’ by Mylène Trublet et al., New J. Chem., 2017, DOI: 10.1039/c7nj03065g.

  • 17.
    Dvoyashkin, Dvoyashkin
    et al.
    aculty of Oil and Gas, Almetyevsk State Oil Institute.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Diffusivity of crude oils contained in macroporous medium: 1H NMR study2018Ingår i: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 2, s. 222-224Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 18.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Azancheev, Nail
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Gibaydullin, Amal
    Institute of Physics, Kazan Federal University, Kazan, Russia.
    Bhattacharyya, Shubhankar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Dynamic Properties of Imidazolium Orthoborate Ionic Liquids Mixed with Polyethylene Glycol Studied by NMR Diffusometry and Impedance Spectroscopy2018Ingår i: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 56, nr 2, s. 113-119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 19.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Kazan State Medical University, Kazan, Russian Federation.
    Kurakin, S.
    Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Gnezdilov, O.I.
    Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry, United Kingdom.
    Effect of magnetic field on diffusion of ethylammonium nitrate: water mixtures confined between polar glass plates2018Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 4, s. 45-51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We used 1H NMR diffusometry to study mixtures of ethylammonium nitrate (EAN) with water (3.1–12.4 mol% of added H2O) confined between polar glass plates and exposed to a static magnetic field of 9.4 T. The presence of such restrictions reverses the concentration dependence of the diffusivities of the EA (ethylammonium) cation and water typical for the bulk system. The presence of water weakens the effects of a static magnetic field on diffusion of the EA cation as well as on proton exchange of –NH3 groups. Surprisingly, the amplitude of the echo signal of water protons decreases during exposure to the magnetic field and finally disappears, a phenomenon that depends on the concentration of water in the system. Based on experimental data, we suggest that water in the system is present in two states with different dynamic properties. One type of water formed in confinement possesses NMR relaxation time typical for liquids; its diffusivity can be measured by 1H NMR. The second type of water is formed upon exposure of the sample of the first type to the magnetic field and eventually includes all the water in the system. This type of water possesses “solid-like” NMR relaxation features that makes it “invisible” to the NMR diffusometry technique. We suggest that this second type of water is adsorbed onto the glass plates. Correspondingly, EAN exists in two liquid phases: the first one contains an EAN-water mixture, while the second one contains neat EAN, and forms on the microscopic scale range under the influence of a static magnetic field.

  • 20.
    Khan, Amir Sada
    et al.
    Center of Research in Ionic Liquids, Department of Chemical Engineering, Universiti Teknologi PETRONAS .
    Man, Zakaria
    Center of Research in Ionic Liquids, Department of Chemical Engineering, Universiti Teknologi PETRONAS .
    Bustam, Mohamad Azmi
    Center of Research in Ionic Liquids, Department of Chemical Engineering, Universiti Teknologi PETRONAS .
    Nasrullah, Asma
    Fundamental and Applied Science Department, Universiti Teknologi PETRONAS .
    Ullah, Zahoor
    Department of Chemistry, Balochistan University of IT, Engineering and Management Sciences (BUITEMS).
    Sarwono, Ariyanti
    Center of Research in Ionic Liquids, Department of Chemical Engineering, Universiti Teknologi PETRONAS .
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Muhammad, Nawshad
    Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore, Pakistan.
    Efficient Conversion of Lignocellulosic Biomass to Levulinic Acid Using Acidic Ionic Liquids2018Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, s. 208-214Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present research work, dicationic ionic liquids, containing 1,1-Bis(3-methylimidazolium-1-yl) butylene ([C4(Mim)2]) cation with counter anions [(2HSO4)(H2SO4)0], [(2HSO4)(H2SO4)2] and [(2HSO4)(H2SO4)4] were synthesised. ILs structures were confirmed using 1H NMR spectroscopy. Thermal stability, Hammett acidity, density and viscosity of ILs were determined. Various types of lignocellulosic biomass such as rubber wood, palm oil frond, bamboo and rice husk were converted into LA. Among the synthesized ionic liquids, [C4(Mim)2][(2HSO4)(H2SO4)4] showed higher % yield of LA up to 47.52 from bamboo biomass at 100 °C for 60 min, which is the better yield at low temperature and short time compared to previous reports. Surface morphology, surface functional groups and thermal stability of bamboo before and after conversion into LA were studied using SEM, FTIR and TGA analysis, respectively. This one-pot production of levulinic acid from agro-waste will open new opportunity for the conversion of sustainable biomass resources into valuable chemicals.

  • 21.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 reflectance2018Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 148, artikel-id 193806Artikel i tidskrift (Refereegranskat)
    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.

  • 22.
    An, Rong
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing.
    Zhou, Guobing
    School of Chemical Biological and Materials Engineering, University of Oklahoma.
    Zhu, Yudan
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University.
    Zhu, Wei
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University.
    Huang, Liangliang
    School of Chemical Biological and Materials Engineering, University of Oklahoma.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Friction of Ionic Liquid–Glycol Ether Mixtures at Titanium Interfaces: Negative Load Dependence2018Ingår i: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 5, nr 14, artikel-id 1800266Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Structural reorientation of alkyl chains in the phosphonium cation of orthoborate ionic liquid mixed with glycol ether occurs with increasing normal load of the AFM tip. The flat reoriented structure, similar to the ‘blooming lotus leaf’, produces a new sliding interface that is responsible for the observed lower friction at higher loads. This work is reported by Rong An, Liangliang Huang, Faiz Ullah Shah and co‐workers in article number 1800263.

  • 23.
    An, Rong
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing.
    Zhou, Guobing
    School of Chemical Biological and Materials Engineering, University of Oklahoma.
    Zhu, Yudan
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University.
    Zhu, Wei
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University.
    Huang, Liangliang
    School of Chemical Biological and Materials Engineering, University of Oklahoma.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Friction of Ionic Liquid–Glycol Ether Mixtures at Titanium Interfaces: Negative Load Dependence2018Ingår i: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 5, nr 14, artikel-id 1800263Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The atomic force microscopy experiments and nonequilibrium molecular dynamics (NEMD) simulations demonstrate a negative friction–load dependence to ionic liquid–glycol ether mixtures, that is, the friction decreases as the normal load increases. NEMD simulations reveal a structural reorientation of the studied ionic liquid (IL): as the normal load increases, the cation alkyl chains of ILs change the orientation to preferentially parallel to the tip scanning path. The flat‐oriented IL structures, similar to the “blooming lotus leaf,” produce a new sliding interface and reduce the friction. A further molecular dynamics simulation is carried out by adopting slit‐pore models to mimic the tip approaching process to confirm the dynamics of ILs. A faster diffusion of ILs in the smaller slit pore is observed. The faster diffusion of ILs in the more confined slit pore facilitates the structural reorientation of ILs. The resulted new sliding surface is responsible for the observed smaller friction at higher loads, also known as the negative friction–load dependence. These findings provide a fundamental explanation to the role of ILs in interfacial lubrications. They help to understand liquid flow properties under confinement, with implications for the development of better nanofluidic devices.

  • 24.
    Shah, Faiz Ullah
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rutland, Mark W.
    Surface and Corrosion Science, Department of Chemistry, KTH Royal Institute of Technology.
    Glavatskih, Sergei
    System and Component Design, KTH Royal Institute of Technology.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, University of Warwick.
    Interfacial Behavior of Orthoborate Ionic Liquids at Inorganic Oxide Surfaces Probed by NMR, IR and Raman Spectroscopy2018Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, nr 34, s. 19687-19698Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Absorption modes and reactivity of non-halogenated ionic liquids (ILs) at inorganic oxide surfaces of γ-Al2O3, MgO and SiO2 particles were characterized using multinuclear (11B, 31P and 29Si) solid-state magic-angle-spinning NMR, FTIR and Raman spectroscopy. ILs are composed of the trihexyl(tetradecyl)phosphonium cation, [P6,6,6,14]+, and bis(mandelato)borate, [BMB]-, or bis(salicylato)borate, [BScB]-, anions. Spectroscopic measurements were performed on room temperature (298 K) samples and samples exposed to 15 hours of heating at 373 K. The single pulse 11B NMR data of heated [P6,6,6,14][BMB] mixed with the inorganic oxides showed a significant change in spectra of the anion for all three oxides. In contrast, no such spectral changes were detected for heated [P6,6,6,14][BScB] mixed with the inorganic oxides. 31P MAS NMR data for the IL/metal oxide systems revealed interactions between [P6,6,6,14]+ and the surfaces of oxides. A significant intensity of 31P CP-MAS NMR signals indicated a low mobility of cations in these systems. The existence of strongly adhered surface layers of ILs on SiO2 particles was also confirmed by 1H-29Si CP-MAS NMR spectroscopy. FTIR and Raman spectroscopic data revealed strong interactions between the anions and the inorganic surfaces and there is strong correlation with the data obtained from NMR spectroscopy. Although their chemical structures are rather similar, the [BScB]- anion is more stable than the [BMB]- anion at the inorganic oxide surface.

  • 25.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russia .
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry, United Kingdom .
    Magnetic field effects dynamics of ethylammonium nitrate ionic liquid confined between glass plates2018Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, nr 9, s. 6316-6320Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 26.
    Rodiouchkina, Maria
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Berglund, Kim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Forsberg, Fredrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rodushkin, Ilia
    ALS Laboratory Group, ALS Scandinavia AB.
    Larsson, Roland
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Material Characterization and Influence of Sliding Speed and Pressure on Friction and Wear Behavior of Self-Lubricating Bearing Materials for Hydropower Applications2018Ingår i: Lubricants, ISSN 2075-4442, Vol. 6, nr 2, artikel-id 39Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nowadays, hydropower plants are forced to have more frequent power control and the self-lubricated bearings used in the applications are one of the most critical components affected by the continuously changing operating conditions. In this study, microstructure and composition of two commercially available bearing materials (Orkot TXM Marine and Thordon ThorPlas) used in hydropower turbines were studied. In addition, the influence of sliding speed and applied pressure on the friction and wear behavior of the materials was investigated systematically for dry sliding conditions. The bearing materials were characterized using X-ray microtomography, Nuclear Magnetic Resonance (NMR) spectroscopy and Inductively Coupled Plasma–Sector Field Mass Spectrometry (ICP-SFMS) techniques. Friction and wear tests were carried out with a polymer pin sliding against a stainless steel (SS2333) plate with a linear reciprocating motion. Test conditions were: room temperature, 9–28 MPa pressure and 10–40 mm/s sliding speed ranges. Surface analysis of the polymer pins and the wear tracks were performed by optical profilometry, Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) techniques. Test results show that, for both materials, the coefficient of friction (COF) is decreasing at higher pressures. Surface analysis reveals higher concentrations of solid lubricants in the transfer layers formed at higher pressures, explaining the decrease in COF. Furthermore, the specific wear rate coefficients are increasing at higher sliding speeds, especially at lower pressures. Results of this study demonstrate that, under dry sliding conditions, changes in sliding speed and pressure have a significant influence on the tribological behavior of these bearing materials.

  • 27.
    Srivastava, K.
    et al.
    Physics Department, University of Lucknow, Lucknow, India.
    Khan, E.
    Physics Department, University of Lucknow, Lucknow, India.
    Shimpi, Manishkumar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Tandon, P.
    Physics Department, University of Lucknow, Lucknow, India.
    Sinha, K.
    Physics Department, University of Lucknow, Lucknow, India.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Molecular structure and hydrogen bond interactions of a paracetamol-4,4′-bipyridine cocrystal studied using a vibrational spectroscopic and quantum chemical approach2018Ingår i: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 20, nr 2, s. 213-222Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of the current study is to perform the structural and spectroscopic characterization of paracetamol-4,4′-bipyridine (PRA-BPY) cocrystal using infrared, Raman spectroscopy and density functional theory (DFT) calculations. To reveal the interactions between PRA and BPY, two models (monomer and dimer + PRA) of a cocrystal are designed and optimized using DFT with a 6-311G (d, p) basis set. An atoms in molecule study shows that the non-covalent interactions in particular hydrogen bonds involved in forming the cocrystal are moderate in nature. Natural bond orbital analysis of the second order perturbation theory of the Fock matrix suggests that interactions LP (1) N13 → π∗(C15-O16) and LP (1) N56 → σ∗(N13-H14) are responsible for the stabilization of the molecule. 

  • 28.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Polymorphism of Alzheimer’s Aβ Amyloid Fibrils and Oligomers2018Ingår i: Modern Magnetic Resonance / [ed] Graham A. Webb, Cham: Springer, 2018, s. 333-347Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

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

  • 29.
    Shimpi, Manishkumar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Giri, Lopamudra
    Indian Institute of Technology Bhubaneswar, Toshali Bhavan, Bhubaneswar.
    Rao Pedireddi, Venkateswara
    Indian Institute of Technology Bhubaneswar, Toshali Bhavan, Bhubaneswar.
    Preparation and Structure Analysis of Three New Copper Complexes of Mellitic Acid With 4,4′-Bipyridine and 1,3-bis(4-pyridyl)Propane2018Ingår i: ChemistrySelect, ISSN 2365-6549, Vol. 3, nr 3, s. 855-858Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Coordination complexes, [Cu-2(H2L)(bpy)(2)].2H(2)O, (1a), [Cu(H3L)(2) (H2O)(4)].(H(2)bpypa)(2).6H(2)O, (2a) and [Cu(H3L)(4)] [Cu(H2O)(6)].(H(2)bpypa)(4).20H(2)O, (2b), of mellitic acid, H6L, with 4,4'-bipyrdine, (bpy), and 1,3-bis(4-pyridyl) propane, (bpypa), have been prepared and the three-dimensional structures are established by single crystal X-ray diffraction unequivocally. The complex 1a was prepared following hydrothermal method, while the complexes 2a and 2b were obtained concomitantly from an aqueous solution at room temperature. In the crystals of 1a, both acid and the aza-donors form coordination bonds with metal ions, while in 2a and 2b coordination bonding prevails between metal and acid molecules only, with azadonor molecules remain intact without coordinating to metal species. Further, 1a and 2b are noted to be yielding a hostguest network, whereas 2a forms planar sheets that are stacked in three-dimensional arrangemen

  • 30.
    Dinesha,
    et al.
    Department of Chemistry, Vivekananda College, Puttur, India.
    Viveka, S.
    Department of Chemistry, Mangalagangotri, Mangalore University, Konaje, India.
    Gowda, Vasantha
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik. NMR Research Group, Faculty of Science, University of Oulu, Oulu, Finland.
    Nagaraja, G.K
    Department of Chemistry, Mangalagangotri, Mangalore University, Konaje, India.
    Review: An experimental (synthesis, NMR and crystallography) and theoretical study of three biologically active diazoles2018Ingår i: Concept, property and application of micro/nanostructured materials / [ed] Li,J. & Du, S., Nova Science Publishers, Inc., 2018, s. 213-232Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The current chapter overview to explain the synthesis of three important class of diazoles namely, pyrazoles, hydroxypyrazolines, and imidazoles followed by elucidation of structure by single-crystal X-ray crystallography, liquid state 1H and density functional theory (DFT) calculations. Our principal interest is focused on the relationship between molecular and/or crystal structure of the synthesized compounds and their efficacy as pharmaceutical drug molecules. Furthermore, they play a significant role as crucial synthetic intermediates. The synthesized molecules were tested for their biological activities like anticancer, antimicrobial, anti-inflammatory, analgesic and antioxidant agents. Strong intermolecular interactions mediated by hydrogen bonding C-H·O or p-p stacking has been observed in X-ray structures most of the molecules. DFT calculations of the NMR chemical shifts for the unambiguous structural assignments of the molecules were performed. Overall, a multidimensional approach has been used for rational design, synthesis and structural characterization of these biologically important molecules. The main goal of this chapter is to review our recent progress in this field. 

  • 31.
    Trublet, Mylène
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rusanova-Naydenova, Daniela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg N
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, CV47AL, UK.
    Revisiting syntheses of Ti(IV)/H2PO4–HPO4functional ion-exchangers, properties and features2018Ingår i: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 42, nr 2, s. 838-845Artikel i tidskrift (Refereegranskat)
    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.

  • 32.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University.
    Gnezdilov, Oleg I.
    Institute of Physics, Kazan Federal University.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Physics, Warwick University, Coventry.
    Static magnetic field alters properties of confined alkylammonium nitrate ionic liquids2018Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 268, s. 49-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) ionic liquids confined between polar glass plates and exposed to a strong magnetic field of 9.4 T demonstrate gradually slowing diffusivity, a process that can be reversed by removing the sample from the magnetic field. The process can be described well by the Avrami equation, which is typical for autocatalytic (particularly, nucleation controlled) processes. The transition can be stopped by freezing the sample. Cooling and heating investigations showed differences in the freezing and melting behavior of the sample depending on whether it had been exposed to the magnetic field. After exposure to the magnetic field, the sample demonstrated decrease in the 1H NMR signal of residual water. 1H NMR spectroscopy with presaturation demonstrates that the most probable mechanism of the decrease of the bulk water signal is adsorption of water on polar surfaces of glass plates. Generally, our findings confirm our previous suggestion that alteration of the dynamic properties of confined alkylammonium nitrate ionic liquids exposed to a magnetic field is related to the alteration of real physical-chemical phases

  • 33.
    Persson, Ingmar
    et al.
    Department of Molecular Sciences, Swedish University of Agricultural Sciences.
    Trublet, Mylene
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Klysubun, Wantana
    Synchrotron Light Research Institute.
    Structure Determination of Phosphoric Acid and Phosphate Ions in Aqueous Solution Using EXAFS Spectroscopy and Large Angle X-ray Scattering2018Ingår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 122, nr 37, s. 7413-7420Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The structures of hydrated phosphoric acid and phosphate ions (H2PO4-, HPO42- and PO43-) in aqueous solution have been determined by P K-edge EXAFS and large angle X-ray scattering (LAXS). The P-O bond distance in all phosphate species studied is close to 1.53 Å. The P-(O)⋅⋅⋅Oaq distances have been refined to ca. 3.6 Å from the LAXS data giving a P-O⋅⋅⋅Oaq bond angle close to tetrahedral suggesting that each oxygen or OH group of phosphoric acid and dihydrogenphosphate, on average, hydrogen bind three water molecules. The (P-)O(-H)···Oaq and (P-)O···(H-)Oaq hydrogen bonds in hydrated phos-phoric acid and the H2PO4- ion are shorter than the hydrogen bonds in neat water. This supports previous infrared spectro-scopic studies claiming that the hydrogen bonds in hydrated phosphoric acid and phosphate ions are stronger than the hy-drogen bonds in neat water. Phosphoric acid and phosphate ions can therefore be regarded as structure making solutes. This is the first study applying transmission mode X-ray absorption spectroscopy (XAS) data collection on the P K-edge. It shows that XAS spectra collected in transmission mode have a much better S/N ratio than data collected in fluorescence mode, allowing accurate determination of P-O bond distances. Furthermore, P K-edge EXAFS data collected in fluorescence mode display a higher amplitude at high k than expected due to increasing radiated volume of the sample with increasing energy as the total absorption decreases sharply with increasing energy of the X-rays. As a result, the fluorescence signal becomes non-proportional to the intensity of the X-ray beam over the EXAFS spectrum. This results in an increasing amplitude of the EXAFS function with increasing energy of the X-ray beam resulting in too small Debye-Waller coefficients.

  • 34.
    Arkhipov, Victor P.
    et al.
    Department of Physics, Kazan National Research Technological University, Kazan, Russia.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Kazan, Russia.
    The cloud point of aqueous solutions of ethoxylated monoalkylphenols in the individual state and in the presence of electrolytes2018Ingår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 39, nr 10, s. 1442-1446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 35.
    Bhattacharyya, Shubhankar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Kaushik, Hatua
    Department of Chemistry, IIEST, Shibpur.
    Theoretical investigation of banert cascade reaction2018Ingår i: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, nr 4, artikel-id 171075Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Computational inside of Banert cascade reaction for triazole formation is studied with B3LYP/6-31G(d,p) level of theory. The reaction proceeds mainly by SN2 initial chloride displacement rather than SN2 -type attack. Furthermore, according to the rate of reaction calculation, SN2 displacement is much faster than SN2 displacement in the order of 8. The [3,3]-sigmatropic rearrangement for the conversion of propargyl azide into triazafulvene has been proved as the rate-determining step having highest activation energy parameter. Solvent effect on total course of reaction has been found negligible. Furthermore, effects of different density functional theory functionals and functional groups on activation energies of [3,3]-sigmatropic rearrangement of propargyl azide were also studied. BHHLYP, ωB97XD, M062X and BMK calculated ∆G are consistent with B3LYP.

  • 36.
    Bhattacharyya, Shubhankar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Thermal stability of choline based amino acid ionic liquids2018Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 266, s. 597-602Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal stability of different choline based amino acid ionic liquids were studied. Both short term as well as long term thermal studies were carried out. Long term thermal studies of all ILs were carried out by isothermal TGA and short term thermal studies were measured by temperature ramped TGA. Isothermal TGA were studied at two different temperatures 100 °C and 150 °C for 500 min. Whereas, short term thermal stability represents as T2%, T5% and T10% which are the temperature at which 2%, 5% and 10% mass loss of ILs were observed. The effect of alkyl side chain on the cation, etherification of the cation as well structural variation of anion on the thermal stability of choline based ILs were investigated. It was observed that thermal characteristics of ILs towards temperature ramped TGA were different compared to isothermal TGA.

  • 37.
    Gusain, Rashi
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Chemical Science Division, CSIR-Indian Institute of Petroleum, Dehradun.
    Panda, Somenath
    Department of Chemistry, Indian Institute of Technology Madras, Chennai.
    Bakshi, Paramjeet Singh
    Chemical Science Division, CSIR-Indian Institute of Petroleum, Dehradun.
    Gardas, Ramesh L.
    Department of Chemistry, Indian Institute of Technology Madras, Chennai.
    Khatri, Om Prakash
    Chemical Science Division, CSIR-Indian Institute of Petroleum, Dehradun.
    Thermophysical properties of trioctylalkylammonium bis(salicylato)borate ionic liquids: Effect of alkyl chain length2018Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 269, s. 540-546Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermophysical properties of halogen-free ionic liquids are gaining significant attention for industrial applications. In this context, trioctylalkylammonium bis(salicylato)borate (N888n-BScB) ionic liquids having variable alkyl chain length (n = 4, 8, 12, 16) are synthesized to explore the effect of chain length and temperature on their physicochemical properties. The density (ρ), refractive index (nD), and speed of sound (u) are measured in the temperature range of 293.15 to 333.15 K. The tetraoctylammonium-BScB is found to be highly dense ionic liquid, and it was attributed to the closer packing of symmetric structure of tetraoctylammonium cation. Furthermore, derived thermodynamic properties such as isentropic compressibility (βs), coefficient of thermal expansion (α), standard entropy (S°), intermolecular free length (Lf) and lattice energy (UPOT) are calculated for the N888n-BScB ionic liquids using the experimental data and shown the effect of variable chain length. This study provides a comprehensive insight on the thermophysical properties of halogen-free ionic liquids.

  • 38.
    Trublet, Mylene
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Titanium(IV) Phosphates: The Next Generation of Wastewater Sorbents2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Treatment of industrial waters containing heavy metal ions is essential before being discharged into the environment. Consequently, European regulations have been established to control and limit the amount of heavy metals released. There is a need to develop efficient water treatment techniques that can remove contaminants with respect to these EU regulations.

    Ion-exchange is one of the processes that is being investigated due to fast kinetics, high treatment capacity and its ability to remove heavy metal ions present in trace amounts. Titanium phosphates (TiP) are a group of inorganic ion-exchangers that have demonstrated to be particularly selective towards transition metal ions in aqueous solutions. Two types of ion-exchange units are present in TiP material, which are –HPO4 and –H2PO4 groups. Their structural characteristic is highly dependent on the synthesis conditions, which include the source of titanium, temperature, reaction time and P2O5:TiO2 ratio. Most of the studies have been performed on amorphous TiP containing a mixture of both exchange units, with –HPO4 groups being predominant; as crystalline TiP and –H2PO4 based TiP  are often obtained in difficult conditions, high temperature (up to 250 °C) and/or long reaction time (up to 30 days) and/or using autoclave. Despite promising properties depicted in batch conditions, very few data in continuous flow systems (fixed-bed columns) have been reported.

    In this work, amorphous TiP composed of entirely –H2PO4 ion-exchange units (TiP1) was synthesized at mild conditions using a TiOSO4 solution and HCl/deionized water as post-synthesis treatments. The sorbent was characterized using a range of techniques (solid-state 31P MAS NMR, Raman, XRD, TGA, BET, Elemental analysis, EXAFS and XANES,) and tested in batch and column set-ups towards single and multi-component waters. The chemical formula of TiP1 was established as TiO(OH)(H2PO4)·H2O and it was found that the synthesis of TiP1 was also dependent on the TiO2/H2SO4 content in the primary titanium solution.

    The material displayed a high maximum exchange capacity of ca. 6.4 meq.g-1, expressed as the sodium uptake. The actual ion-exchange capacity towards divalent metal ions was calculated to be ca. 3.4 meq.g-1 in batch condition and up to 4.1 meq.g-1 in fixed-bed column, which is to date the highest recorded for TiP materials. Kinetics of the exchange processes have been studied and the equilibrium was reached within 5-20 minutes. Modeling of the breakthrough curves was achieved using the Thomas model, indicating that the rate driving forces of the processes follow second-order reversible kinetics. The TiP1 sorbent has shown to maintain a high selectivity towards heavy metal ions in multi-component systems (including closed-mine waters) when column studies were performed. The sorption behavior of TiP1 in batch experiments correlates very well with data obtained in fixed-bed column conditions, confirming that prediction of the sorption behavior on the basis of batch data is conceivable.

    Another important aspect of this work also involves the mild syntheses of crystalline α-TiP, Ti(HPO4)·H2O, and LTP (Linked Titanium Phosphate) composed of α-TiP and TiP1, where the structural characteristics of these materials were investigated using solid-state NMR, XRD, TGA, EXAFS and XANES.

  • 39.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Gnezdilov, Oleg I.
    Institute of Physics, Kazan Federal University.
    Hjalmarsson, Nicklas
    Surface and Corrosion Science, KTH Royal Institute of Technology.
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 plates2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 38, s. 25853-25858Artikel i tidskrift (Refereegranskat)
    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.

  • 40.
    Ivanov, Maxim A.
    et al.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences .
    Gerasimenko, Andrey V.
    Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences.
    Merkulov, Eugene B.
    Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences.
    An example of S,S′-bidentate coordination mode of the dithiophosphate group in the heteroleptic tetraphenylantimony(V) complex, [Sb(C6H5)4{S2P(O-cyclo-C6H11)2}]: multinuclear (13C, 31P) CP MAS NMR, single-crystal X-ray diffraction studies and thermal behaviour2017Ingår i: Polyhedron, ISSN 0277-5387, E-ISSN 1873-3719Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Crystalline O,O′-di-cyclo-hexyl dithiophosphate (Dtph) tetraphenylantimony(V) complex, [Sb(C6H5)4{S2P(O-cyclo-C6H11)2}] (1) was prepared and studied by means of heteronuclear (31C, 31P) CP MAS NMR spectroscopy, single-crystal X-ray diffraction and thermal analysis. To characterise quantitatively the phosphorous site in complex 1, 31P chemical shift anisotropy parameters (δaniso and η) were successfully defined from spinning sideband manifolds in experimental MAS NMR spectra. The positive sign of the calculated δaniso unambiguously reveals the terminal S,S′-chelating structural function of di-cyclo-hexyl Dtph groups; whereas, the minimal δ22 value among all presently known tetraphenylantimony(V) dialkyl Dtphs points out to extremely low value of the S–P–S angle. Distorted octahedral molecular structure comprising Dtph ligand with S,S′-bidentate chelating coordination mode has been established for the prepared complex. Therefore, in comparison with tetraphenylantimony(V) Dtph complexes containing S-unidentately coordinated Dtph groups, terminally chelating di-cyclo-hexyl Dtph ligand of crystalline complex 1 expectedly exhibits the smallest S–P–S angle of 113.49°. The thermal behaviour of this compound was studied by means of thermal analysis technique as a combination of TG and DSC. The thermal decomposition involves the organic and inorganic parts of 1, yielding almost equal quantities of Sb2S3 and SbPO4, which were identified using powder XRD.

  • 41.
    Korneeva, E.V.
    et al.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, Blagoveshchensk.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 behavior2017Ingår i: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 43, nr 4, s. 223-231Artikel i tidskrift (Refereegranskat)
    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.

  • 42.
    Gowda, Vasantha
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Experimental and Computational Magnetic Resonance Studies of Selected Rare Earth and Bismuth Complexes2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The rare-earth elements (REEs) and bismuth, being classified as the ‘most critical raw materials’ (European Raw Materials Initiatives, 2017), have a high economic importance to the EU combined with a high relative supply risk. REEs are highly important for the evolving technologies such as clean-energy applications, high-technology components, rechargeable batteries, permanent magnets, electric and hybrid vehicles, and phosphors monitors.This scientific research work aims at building a fundamental knowledge base concerning the electronic/molecular structure and properties of rare-earth element (REE) and bismuth complexes with dithiocarbamate (DTC) and 1,10-phenanthroline (PHEN) by employing state-of-the-art experimental techniques such as nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction (XRD) techniques together with ab initioquantum mechanical computational methods. This combination of methods has played a vital role in analysing the direct and significant effect of the heavy metal ions on the structural and magnetic resonance properties of the complexes, thereby, providing a framework of structure elucidation. This is of special importance for REEs, which are known to exhibit similar chemical and physical properties. The objectives of the work involve i) a systematic investigation of series of REE(III) as well as bismuth(III) complexes to get a profound understanding of the structure-properties relationship and ii) to find an appropriate theoretical modelling and NMR calculation methods, especially, for heavy metal systems in molecular and/or solid-state. This information can later be used in surface interaction studies of REE/bismuth minerals with DTC as well as in design and development of novel ligands for extraction/separation of metal ions.The REE(III) and bismuth(III) complexes with DTC and PHEN ligands have all provided aunique NMR fingerprint of the metal centre both in liquid and solid phase. The solid-state 13C and 15NNMR spectra of the diamagnetic REE(III) and bismuth(III) complexes were in accord with their structural data obtained by single crystal XRD. The density functional theory (DFT) methods were used to get complementary and refined structural and NMR parameters information for all diamagnetic complexes in the solid-state. The relativistic contributions due to scalar and spin-orbit correlations for the calculated 1H/13C/15N chemical shifts of REE complexes were analysed using two-component zeroth-order regular approximation (ZORA)/DFT while the ‘crystal-lattice’ effects on the NMR parameters were calculated by combining DFT calculations on molecular and periodic solid-state models. The paramagnetic REE complexes display huge differences in their 1H and 13C NMR spectral patterns. The experimental paramagnetic NMR (pNMR) chemical shifts, as well as the sizable difference of the 1H and 13C NMR shifts for these isoelectronic complexes, are well reproduced by the advanced calculations using ab initio/DFT approach. The accuracy of this approach is very promising for further applications to demanding pNMR problems involving paramagnetic f-block elements.The results presented in this thesis demonstrate that a multidisciplinary approach of combined experimental NMR and XRD techniques along with computational modelling and property calculations is highly efficient in studying molecular complexes and solids containing heavy metal systems, such as rare-earths and bismuth.

  • 43.
    Bhattacharyya, Shubhankar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University, Russia.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    High CO2 absorption capacity by chemisorption at cations and anions in choline-based ionic liquids2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 46, s. 31216-31226Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 44.
    Shah, Faiz Ullah
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Oleg, Gnezdilov
    Institute of Physics, Kazan Federal University .
    Filippov, Andrei
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Institute of Physics, Kazan Federal University.
    Ion dynamics in halogen-free phosphonium bis(salicylato)borate ionic liquid electrolytes for lithium-ion batteries2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 25, s. 16721-16730Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study was focused on the investigation of ion dynamics in halogen-free, hydrophobic, and hydrolytically stable phosphonium bis(salicylato)borate [P4,4,4,8][BScB] ionic liquid electrolytes for lithium-ion batteries. The structure and purity of the synthesized ionic liquid and lithium bis(salicylato)borate Li[BScB] salt were characterized using 1H, 13C, 31P, and 11B NMR spectroscopy. The Li[BScB] salt was mixed with an ionic liquid at the concentrations ranging from 2.5 mol% to 20 mol%. The physicochemical properties of the resulting electrolytes were characterized using thermal analysis (TGA and DSC), electrical impedance spectroscopy, and pulsed-field gradient (PFG) NMR and ATR-FTIR spectroscopy. The apparent transfer numbers of the individual ions were calculated from the diffusion coefficients of the cation and anion as determined via the PFG NMR spectroscopy. NMR and ATR-FTIR spectroscopic techniques revealed dynamic interactions between the lithium cation and bis(salicylato)borate anion in the electrolytes. The ion–ion interactions were found to increase with the increasing concentration of the Li[BScB] salt, which resulted in ionic clustering at the concentrations higher than 15 mol% of Li salt in the ionic liquid.

  • 45.
    Kumari, Sangita
    et al.
    Chemical Science Division, CSIR-Indian Institute of Petroleum, Dehradun .
    Mungse, Harshal P.
    Department of Materials Science and Engineering, Kyoto University.
    Gusain, Rashi
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Kumar, Niranjan
    Materials Science Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam .
    Sugimura, Hiroyuki
    Department of Materials Science and Engineering, Kyoto University.
    Khatri, Om P.
    Chemical Science Division, CSIR-Indian Institute of Petroleum, Dehradun .
    Octadecanethiol-grafted molybdenum disulfide nanosheets as oil-dispersible additive for reduction of friction and wear2017Ingår i: FlatChem, ISSN 2452-2627, Vol. 3, s. 16-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Molybdenum disulfide (MoS2) easily shears at the contact interfaces because of weak interplaner interaction and exhibits high mechanical strength, which promises its potential for tribological applications. However, poor dispersibility of MoS2 in the lube oils has been a great challenge. Herein, a facile and scalable hydrothermal approach is presented to synthesize the MoS2 nanosheets and then chemically functionalized with octadecanethiol (ODT). The structural defects and vacant sulfur sites on the Mo-atoms of MoS2 nanosheets are targeted for grafting of ODT via Mo-S dative linkage. The chemical and structural features of MoS2-ODT are characterized by FTIR, XPS, XRD and HRTEM analyses. The dispersion stability of MoS2-ODT nanosheets in the polyol ester lube oil is examined by UV–Visible spectroscopy. The van der Waals interaction between the octadecyl chain of MoS2-ODT and oleate chains of polyol ester lube oil facilitates the dispersion of MoS2-ODT nanosheets. Tribological results revealed that minute dosing (0.05 mg.mL−1) of thoroughly dispersed MoS2-ODT nanosheets, as an additive to polyol lube oil, significantly reduced the friction and the wear of steel tribo-pair. The uninterrupted supply of MoS2-ODT nanosheets on the tribo-contacts, formation of MoS2 thin film on tribo-interfaces, ease of shearing driven by weak van der Waals interaction between MoS2 lamellae and high mechanical strength of MoS2, collectively enhanced the tribo-performance, when thoroughly dispersed MoS2-ODT was used as an additive to the polyol lube base oil.

  • 46.
    Shimpi, Manishkumar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Pharmaceutical Crystal Engineering Using Ionic Liquid Anion–Solute Interactions2017Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 17, nr 4, s. 1729-1734Artikel i tidskrift (Refereegranskat)
    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.

  • 47.
    Geng, Shiyu
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Shah, Faiz Ullah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Liu, Peng
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Plasticizing and crosslinking effects of borate additives on the structure and properties of poly(vinyl acetate)2017Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, nr 13, s. 7483-7491Artikel i tidskrift (Refereegranskat)
    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.

  • 48.
    Ahmed, Hamzah
    et al.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Shimpi, Manishkumar R.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Velaga, Sitaram P.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Relationship between mechanical properties and crystal structure in cocrystals and salt of paracetamol2017Ingår i: Drug Development and Industrial Pharmacy, ISSN 0363-9045, E-ISSN 1520-5762, Vol. 43, nr 1, s. 89-97Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objectives were to study mechanical properties of various solid forms of paracetamol and relate to their crystal structures. Paracetamol Form I (PRA), its cocrystals with oxalic acid (PRA-OXA) and 4,4-bipyridine (PRA-BPY) and hydrochloride salt (PRA-HCL) were selected. Cocrystals and salt were scaled-up using rational crystallization methods. The resulting materials were subjected to differential scanning solid-state characterization. The powders were sieved and 90-360 µm sieve fraction was considered. These powders were examined by scanning electron microscopy (SEM) and densities were determined. Tablets were made at applied pressures of 35-180 MPa under controlled conditions and the tablet height, diameter and hardness were measured. Tensile strength and porosity of the tablets were estimated using well known models. Crystal structures of these systems were visualized and slips planed were identified. Cocrystal and salt of PRA were physically pure. Sieved powders had comparable morphologies and particle size. The apparent and theoretical densities of powders were similar but no clear trends were observed. The tensile strengths of these compacts were increased with increasing pressure whereas tabletability decreased in the order oxalic acid > PRA-HCL ≈ PRA-OXA > BPY > PRA-BPY. Tablet tensile strength decreases exponentially with increasing porosity with the exception of PRY-BPY and BPY. Slip plane prediction based on attachment energies may not be independently considered. However, it was possible to explain the improved mechanical properties of powders based on the crystal structure. Cocrystallization and salt formation have introduced structural features that are responsible for improved tableting properties of PRA.

  • 49.
    Trublet, Mylene
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Sorption performances of TiO(OH)(H2PO4)·H2O in synthetic and mine waters2017Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, nr 4, s. 1989-2001Artikel i tidskrift (Refereegranskat)
    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.

  • 50.
    Gowda, Vasantha
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. 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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. 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 calculations2017Ingår i: Polyhedron, ISSN 0277-5387, E-ISSN 1873-3719, Vol. 129, s. 123-132Artikel i tidskrift (Refereegranskat)
    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.