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  • 1.
    Aas, Wenche
    KTH, Superseded Departments, Chemistry.
    Constitution, dynamics and structure of binary and ternary actinide complexes1999Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Stoichiometry, ligand exchange reactions, coordinationgeometry and stability of complexes of type UO2LpFq(H2O)3-n(p= 1–2,q= 1-3), where L is one of the bidentate ligandspicolinate, oxalate, carbonate or acetate have beeninvestigated using single crystal X-ray diffraction, an arrayof19F-,13C-,17O- and1H-NMR techniques and potentiometric titration usingboth F-and H+selective electrodes. The experiments wereperformed in a 1.00 M NaClO4medium. The equilibrium constants were determinedat 25°C while most of the kinetic experiments were done at- 5°C. The equilibrium constants for the stepwise additionof F-to UO2L and UO2L2indicates that the prior coordination of L toU(VI) has a fairly small effect on the subsequent bonding offluoride, except for a statistical effect determined by thenumber of available coordination sites. This indicates thatternary complexes might be important for the speciation andtransport of hexavalent actinides in ground and surface watersystems. A single crystal structure of UO2(picolinate)F32-has been determined showing the same pentagonalbipyramidal symmetry as in aqueous solution studied by NMR. Theexchangeable donor atoms are situated in a plane perpendicularto the linear uranyl group. The complexes show a variety ofdifferent exchange reactions depending on the ligand used. Ithas been possible to quantify external fluoride and the otherligands exchange reactions as well asintra-molecular reactions. This type of detailedinformation has not been observed in aqueous solution before.Water takes a critical part in the exchange mechanism, and whenit is eliminated from the inner coordination sphere a muchslower kinetics can be observed.19F-NMR has showed to be a powerful technique tostudy these reactions, both because of the sensitivity of thisNMR nucleus and also the possibility to observe reactions wherefluoride is not directly involved in the mechanism. TernaryTh(edta)F1-2and (UO2)2(edta)2F1-4have been investigated using1H and19F-NMR. The fluoride complexation to Cm(III) wasstudied using time resolved fluorescence spectroscopy (TRLFS)and the stability constant for the CmF2+complex was determined at 25°C in 1.0 mNaCl.

    Keywords. Ternary complexes, actinides,dioxouranium(VI), curium(III), thorium(IV), ligand exchange,isomers, NMR, potentiometric titrations, aqueous solution,oxalate, picolinate, acetate, EDTA.

  • 2. Aberg, V.
    et al.
    Bostrom, D.
    Fischer, Andreas
    KTH, Superseded Departments, Chemistry.
    Almqvist, F.
    Synthesis and absolute configuration of methyl(-)-(3R)-8-(4-bromophenyl)-7-(naphthalen-1-yl-methyl)-5-oxo-2,3-dihydro-5H-thiazolo 3,2-a pyridine-3-carboxylate2002In: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 58, p. o812-o814Article in journal (Refereed)
    Abstract [en]

    The title molecule, C26H20BrNO3S, contains a ring-fused 2-pyridinone framework substituted with a 4-bromo-phenyl-, a naphthalen-1-ylmethyl and a methoxycarbonyl substituent. The main goal of this work was to confirm the stereochemistry for the methoxycarbonyl substituent, which proved to be 3R. Moreover, the 4-bromophenyl substituent was shown to be rotated out of the plane of the 2-pyridinone ring, with a torsion angle of 61.2 (5)degrees. To allow the best packing arrangement, the naphthalen-1-ylmethyl substituent is positioned to mediate an intermolecular pi-pi interaction.

  • 3.
    Abili Nejad, Maryam
    KTH, Superseded Departments, Chemistry.
    Kinetics for oxidation of CRUD model compounds2004Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The formation of CRUD (Chalk River Unidentified Deposit) inwater-cooled nuclear reactors constitute a severe problem. Thestability of CRUD under reactor conditions (high flux ofionizing radition, high temperature and pressure) must be knownin order to minimize the problem. The kinetics for CRUDoxidation by H2O2 and the two more potent oxidants IrCl62-and MnO4- has been studied using aqueous suspensions ofthree metal oxide powders, Fe3O4, Fe2CoO4 and Fe2NiO4. The metal oxides were used as model compounds forCRUD. The latter two oxidants were employed to study therelationship between kinetics and the reduction potential ofthe oxidant. In addition, the activation energies for thereaction between H2O2and the three metal oxides of CRUD model weredetermined. The mechanism of the reaction is discussedindicating that the final solid product in all three cases isFe2O3. Our experimental results show that the reactivityof the metal oxides towards oxidants is in the order Fe2CoO4>Fe3O4>Fe2NiO4. The relative reactivities of Fe2CoO4 and Fe3O4are in contrast with that expected from the studyof the ionization potentials of the divalent metals in theoxides. In addition to the experimental studies, thetheoretical grounds for kinetics of reactions in particlesolutions are discussed. The theoretical discussion is alsoused to explain the somewhat unexpected trends in reactivityobserved experimentally. The same reaction trend is alsoobserved in the reaction of the metal oxides with IrCl62-and MnO4-.

    We found experimentally that the logarithm of second orderrate constants of the reaction of metal oxides with oxidantsagainst the one electron potential of the oxidants follows aparabolic behavior in agreement with the Marcus theory forelectron transfer reactions. This work constitutes a good basisfor the design of further model studies aiming at resolving thestability of CRUD under reactor conditions.

    Keywords:Reactor Chemistry, Radiolysis, Oxidation,Kinetics, CRUD, Metal oxide

  • 4. Abraham, T.
    et al.
    Kumpulainen, A.
    Xu, Z.
    Rutland, Mark W
    KTH, Superseded Departments, Chemistry.
    Claesson, Per M.
    KTH, Superseded Departments, Chemistry.
    Masliyah, J.
    Polyelectrolyte-mediated interaction between similarly charged surfaces: Role of divalent counter ions in tuning surface forces2001In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 26, p. 8321-8327Article in journal (Refereed)
    Abstract [en]

    The effects of divalent salts (CaCl2, MgCl2 and BaCl2) in promoting the adsorption of weakly charged polyelectrolyte (polyacrylic acid), PAA, Mw similar to 250000 g/mol) on mica surfaces and their role in tuning the nature of interactions between such adsorbed polyelectrolyte layers were studied using the interferometric surface forces apparatus. With mica surfaces in 3 mM MgCl2 solutions at pH similar to8.0-9.0, the addition of 10 ppm PAA resulted in a long-range attractive bridging force and a short-range repulsive steric force. This force profile indicates a low surface coverage and weak adsorption. The range of the force can be related to the characteristic length scale R-G of polyelectrolyte chains using a scaling description. An increase of the PAA concentration to 50 ppm changed the attractive force profile to a monotonic, long-range repulsive interaction extending up to 600 Angstrom due to the increased surface coverage of polyelectrolyte chains on the mica surfaces. Comparison of the measured forces with a scaling mean field model suggests that the adsorbed polyelectrolyte chains are stretched, which eventually give rise to the polyelectrolyte brush like structure. When the mica surfaces were preincubated in 3 mM CaCl2 at pH similar to8.0-9.0, in contrast to the case of 3 MM MgCl2, the addition of 10 ppm PAA resulted in a more complex force profile: long-range repulsive forces extending up to 800 Angstrom followed by an attractive force regime and a second repulsive force regime at shorter separations. The long-range electrosteric forces can be attributed to strong adsorption of polyelectrolyte chains on mica surfaces (high surface coverage) which is facilitated by the presence of Ca2+ ions, while the intermediate range attractive forces can be ascribed to Ca2+ assisted bridging between adsorbed polyelectrolyte chains. Also interesting is to note various relaxation processes present in this system. In contrast to both MgCl2 and CaCl2 systems, with mica surfaces in 3 mM BaCl2 solution at pH similar to8.0-9.0, the addition of 10 ppm PAA resulted in precipitation of polyelectrolyte chains on mica surfaces, resulting in an extremely long-range monotonic repulsive force profile. In summary, our study showed that divalent counterions (Mg2+, Ca2+, and Ba2+) exhibit significantly different behavior in promoting PAA adsorption on mica surfaces, modifying and controlling various surface interactions.

  • 5.
    Allared, Fredrik
    KTH, Superseded Departments, Chemistry.
    Synthesis of new building blocks for conjugated oligomers2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis deals with the synthesis of new organicmaterials for electronic applications. Several new ring-formingmethods are employed to construct sulphur heterocycles: Tandemelectrophilic aromatic substitution and acid-catalyzedtransetherification of methoxythiophene, double electrophilicaromatic substitutions with ethane-1, 2-disulphenyl chloride,and also, the reaction of dienes with sulphur dichloride. Twonew condensed thiophenes have been incorporated in end-cappedoligothiophenes. An improvement of the synthesis of [3,2-b:2’, 3-d]thiophene is reported, with some attempts toincorporate it in oligomers. A synthesis of substitutednaphthalenes is also described. A new method of producingdisubstituted thiophenes from substituted butadienes anssulphur dichloride is employed in a new route to 3, 4-ethylenedioxythiophene, a very important monomer for conductingpolymers.

    Keywords :Organic Semiconductors, Thiophenes,Heterocyclic Synthesis, Dithienothiophene, Naphthalene,Ethylenedioxythiophene

  • 6. Anderson, M. E.
    et al.
    Aslan, D.
    Clarke, A.
    Roeraade, Johan
    KTH, Superseded Departments, Chemistry.
    Hagman, G.
    Evaluation of generic chiral liquid chromatography screens for pharmaceutical analysis2003In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1005, no 02-jan, p. 83-101Article in journal (Refereed)
    Abstract [en]

    Two different automated generic liquid chromatography screens for the separation of chiral compounds of pharmaceutical interest have been evaluated. The test set comprised 53 chemically diverse chiral compounds involving 55 enantiomeric pairs from the pharmaceutical industry (i.e. starting materials, synthetic intermediates and drug substances). The first screen utilised four polysaccharide-based columns with five mobile phases and showed enantioselectivity for 87% of the test compounds. The second screen employed three macrocyclic glycopeptide columns with two mobile phases and showed enantioselectivity for 65% of the test compounds. Merging of the two screening procedures resulted in an enantioselectivity for 96% of the chiral compounds. It is anticipated that the systematic use of the automated chiral HPLC screens described in this report will substantially reduce the necessary time for method development of pharmaceutically related chiral analytical methods.

  • 7.
    Andersson, Fredrik
    KTH, Superseded Departments, Chemistry.
    1. Asymmetric aldol and alkylation reactions using pyrrolidine-based chiral auxiliaries 2. Syntheses of pine sawfly pheromone precursors and structurally related compounds2002Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis describes the syntheses of the 1-propionylatedauxiliaries (S)-(− )-2-(pyrrolidin-2-yl)propan-2-ol and (S)-(− )-2-(1-methoxy-1-methylethyl)pyrrolidine andtheir use in asymmetric aldol and alkylation reactions. Thesynthesis of 1-propionylated (2S,4R) 2-{4-[(tert-butyldimethylsilyl)oxy]pyrrolidin-2-yl}propan-2-olis also described. The effects on the stereoselectivity, byvariations of solvent, temperature, Lewis acids as additive aswell as the amount of additive are studied. None of thepropionylated auxiliaries exhibited remarkable selectivity foreither diastereomer in aldol reactions with benzaldehyde. Bestresults were obtained with SnCl2as additive giving asyn:antiratio up to 73:27, and Cp2ZrCl2and Cp2TiCl2giving a reversedsyn:antiratio up to 27:73 for the former auxiliary. Highselectivity for onesynand oneantidiastereomer were obtained with TMS-Cl as anadditive. The latter propionylated auxiliary was less selectivethan the former. Reversal insyn/antiselectivity was observed when Cp2ZrCl2and Cp2TiCl2was used with asyn:antiratio = 68:32 and 33:67. In alkylation reactions,the former propionylated auxiliary showed lower and similarselectivity with benzyl bromide andn-butyl iodide, compared with the literature. Enhancedselectivity was obtained in the benzylation reactions (78% and84% diastereomeric excess), with LiCl and Cp2ZrCl2as additives. Cp2ZrCl2and Cp2TiCl2resulted in lower selectivity in butylationreactions. High selectivity was obtained for the latterpropionylated auxiliary and with a reversal in selectivity,compared with the former. Benzylation reactions resulted in82-98% diastereomeric excess, with the highest selectivity ofCp2ZrCl2as additive. In butylation reactions the use ofLiCl resulted in highest diastereomeric excess (94%).

    The second part of the thesis describes the syntheses ofcompounds related to sex pheromones of pine sawflies. (2S,6R)-(− )-2,6-Dimethyl-1-octanol, a building blockin the synthesis of the sex pheromone of the pine sawflyMicrodiprion pallipesin high stereoisomeric purity wasprepared from the optically pure (S)-citronellal. Lipase-catalysed (Amano PS and Im-CRL)kinetic separations, based on selective acylation andesterification of (2R/S,6R)-2,6-dimethyl-1-octanol and the corresponding acidwere the key steps in this sequence. The alcohol precursors tosex pheromones ofDiprion nipponica,Macrodiprion nemoralisandMicrodiprion pallipeswere synthesised as racemicmixtures in moderate yields. Stereoisomeric mixtures of severalmethyl-branched long-chain 2-alkanols, structurally related tosex pheromone alcohol precursors of pine sawfly species, werealso synthesised in moderate yields. The key reaction in thesyntheses was the ring opening of&#947-butyrolactonesusing different alkyl lithiums as nucleophiles.

    Keywords: Chiral auxiliary, Stereoselectivity, Lewisacid, Aldol, Alkylation, Sex pheromone, Pine sawfly, Lipase,Synthesis, Diprion nipponica, Macrodiprion nemoralis,Microdiprion pallipes

  • 8.
    Andersson, Greger
    KTH, Superseded Departments, Chemistry.
    Novel nonlinear multivariate calibration methods1998Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The interest fornonlinear modeling has increasedconcomitantly with the increased awareness of the ubiquity ofnonlinear systems. The traditional solution in analyticalchemistry, to linearize the system by some sort of samplepretreatment, is not always an option in process analyticalchemistry. Sample pretreatment merely introduces unwantedsources of error. The analysis should be performed in-line, orat least on-line, and facilitate a rapid prediction of keyprocess parameters.

    Keywords: multivariate calibration, nonlinear modeling,PLS, neural networks, linearing transform

  • 9.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    Jonsson, C.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Consecutive microcontact printing - ligands for asymmetric catalysis in silicon channels2001In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 79, no 1, p. 78-84Article in journal (Refereed)
    Abstract [en]

    Consecutive microcontact printing ( mu CP) has been developed to enable multiple functionalization of silicon surfaces, such as the immobilization of chiral ligands. The technique involves two subsequent printing steps using unstructured poly(methylsiloxane) stamps. The pattern is already defined on the substrate, consisting of etched channels. Hence, no precise alignment is needed between the two printing steps. A carboxylic acid group containing reagent was initially printed onto the silicon oxide surface and transformed to an anhydride. hi the second printing step an ester bond was formed with the hydroxy-functionalized ligand. The formed molecular layers were evaluated by contact angle measurements, scanning electron microscopy (SEM) and electron spectroscopy for chemical analysis (ESCA), indicating that the consecutive mu CP was successful. Initially, printing was performed on planar silicon surfaces but to realize a flow-through microfluidic device for high throughput screening a mu CP technique was developed for etched channels. To verify the technique, hydrophobic valves consisting of octadecyltrichlorosilane were formed using mu CP in deep reactive ion etched channels (50 mum wide and 50 mum deep). The printed hydrophobic patches were visualized by SEM and functioned well. Finally, the consecutive mu CP technique was applied to immobilize the ligand in the channels. The channels were then sealed with a low-temperature bonding technique using an adhesive PDMS film, which does not destroy the printed ligand. In this study mu CP is used in a novel manner. It enables a convenient method for performing complex surface modification of etched structures, which is a frequently appearing problem in biochemical microfluidic systems.

  • 10.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    Jonsson, C.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Patterned self-assembled beads in silicon channels2001In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 22, no 18, p. 3876-3882Article in journal (Refereed)
    Abstract [en]

    A novel technique enabling selective bead trapping in microfluidic devices without the use of physical barriers is presented in this paper. It is a fast, convenient and simple method, involving microcontact printing and self-assembly, that can be applied to silicon, quartz or plastic substrates. In the first step, channels are etched in the substrate. The surface chemistry of the internal walls of the channels is then modified by microcontact printing. The chip is submerged in a bead slurry where beads self-assemble based on surface chemistry and immobilize on the internal walls of the channels. Silicon channels (100 mum wide and 50 mum deep) have been covered with monolayers of streptavidin-, amino- and hydroxy-functionalized microspheres and resulted in good surface coverage of beads on the channel walls. A high-resolution pattern of lines of self-assembled streptavidin beads, as narrow as 5 mum, has also been generated on the bottom of a 500 mum wide and 50 mum deep channel. Flow tests were performed in sealed channels with the different immobilized beads to confirm that the immobilized beads could withstand the forces generated by water flowing in the channels. The presented results indicate that single beads can be precisely positioned within microfluidic devices based on self-assembly which is useful as screening and analysis tools within the field of biochemistry and organic chemistry.

  • 11.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    Jonsson, C.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Self-assembled and self-sorted array of chemically active beads for analytical and biochemical screening2002In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 56, no 2, p. 301-308Article in journal (Refereed)
    Abstract [en]

    A technique for generating a general screening platform consisting of dots of immobilized beads on silicon has been developed via self-sorting and -assembly of different kinds of beads. The dots are defined by a teflon-like film, which due to its hydrophobic characteristics also prevents cross-contamination of liquid from different dots. To enable functionalization of individual dots with different target molecules simultaneously a new way of microcontact printing has been explored where different target solutions are printed in parallel using one stamp. In order to show that this platform can be designed for both biochemical assays and organic chemistry, streptavidin-, amino- and hydroxy-functionalized beads have been self-sorted and -assembled both on separate and common platforms. The self-sorting and -arrangement are based on surface chemistry only, which has not previously been reported. Beads of different sizes and material have successfully been immobilized in line patterns as narrow as 5 mum. Besides silicon, quartz and polyethylene have also been used as substrates.

  • 12. Andersson, J.
    et al.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Wiklund, C.
    Antiaphrodisiacs in pierid butterflies: A theme with variation!2003In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 29, no 6, p. 1489-1499Article in journal (Refereed)
    Abstract [en]

    Male Pieris napi butterflies previously have been shown to synthesize and transfer an antiaphrodisiac, methyl salicylate (MeS), to females at mating. This substance curtails courtship and decreases the likelihood of female remating. Here, we show that similar systems occur in Pieris rapae and Pieris brassicae. In P. rapae, C-13-labeling studies showed that males utilize the amino acids phenylalanine and tryptophan as precursors to MeS and indole, respectively. These volatiles are transferred to females at mating and function as antiaphrodisiacs, as demonstrated by field tests entailing painting MeS, indole, or a mixture on the abdomens of virgin females and assessing their attractiveness to wild males. With P. brassicae, C-13-labeling studies showed that males use phenylalanine as a precursor to synthesize benzyl cyanide, which was demonstrated to function as an antiaphrodisiac by field tests similar to those for P. rapae. This communication system exhibits both similarities and differences among the three species; in P. napi and P. rapae, males are fragrant but transfer a volatile antiaphrodisiac to females that is completely different from the male odor, whereas in P. brassicae the antiaphrodisiac transferred by male to female is identical with male odor.

  • 13. Andersson, J.
    et al.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Wiklund, C.
    Sexual cooperation and conflict in butterflies: a male-transferred anti-aphrodisiac reduces harassment of recently mated females2000In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 267, no 1450, p. 1271-1275Article in journal (Refereed)
    Abstract [en]

    Sexual selection theory predicts that the different selection pressures on males and females result in sexual conflict. However, in some instances males and females share a common interest which could lead to sexual cooperation. In the pierid butterfly Pieris napi the male and the recently mated female share a common interest in reducing female harassment by other males soon after mating. Here we show that P. napi males transfer an anti-aphrodisiac to the female at mating, methyl-salicylate (MeS), which is a volatile substance which mated females emit when courted and which makes males quickly abandon them. A C-13-labelling experiment demonstrated that only males synthesize MeS. The effect of this antiaphrodisiac is so strong that most males will refrain from mating with virgin females to whom MeS has been artificially applied. In P. napi, males also transfer nutrients to females at mating. This increases female fecundity and longevity and so females benefit from remating. Hence, sexual cooperation gradually turns to conflict. Future research is required to reveal which sex controls the gradual decrease in the MeS titre which is necessary for allowing mated females to regain attractiveness and remate.

  • 14.
    Andersson, Johan
    KTH, Superseded Departments, Chemistry.
    Odour Communication in Pieris Butterflies2004Doctoral thesis, comprehensive summary (Other scientific)
  • 15.
    Andersson, Johan
    et al.
    KTH, Superseded Departments, Chemistry.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Wiklund, C.
    Sexual conflict and anti-aphrodisiac titre in a polyandrous butterfly: male ejaculate tailoring and absence of female control2004In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 271, no 1550, p. 1765-1770Article in journal (Refereed)
    Abstract [en]

    Males of the green-veined butterfly Pieris napi synthesize and transfer the volatile methyl salicylate (MeS) to females at mating, a substance that is emitted by non-virgin females when courted by males, curtailing courtship and decreasing the likelihood of female re-mating. The volatile is released when females display the 'mate-refusal' posture with spread wings and elevated abdomen, when courted by conspecific males. Here, we assess how the amount of MeS released by courted females changes over time since mating, and whether it is influenced by the frequency with which females display the mate-refusal posture. We also assess whether males tailor the anti-aphrodisiac content of ejaculates with respect to the expected degree of sperm competition, by comparing how males allocate MeS proportionately to first and second ejaculates in relation to ejaculate mass. The results show that females housed for 5 days in individual cages where they were able to fly and oviposit normally, released similar amounts of MeS. However, females housed together for the same period of time, causing them to frequently display the mate-refusal posture, released significantly lower levels of MeS than the individually housed females. This indicates that female display of the mate-refusal posture depletes their anti-aphrodisiac stores, and suggests that females are unable to voluntarily control their release of the anti-aphrodisiac. A comparison of relative proportion of MeS transferred by males in their first and second ejaculates showed that proportionately more MeS was allocated to the first ejaculate, in accordance with the idea that these are tailored to delay female re-mating.

  • 16.
    Andersson, Karin M.
    KTH, Superseded Departments, Chemistry.
    Aqueous Processing of WC-Co Powders2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The object of this work is to obtain a fundamentalunderstanding of the principal issues concerning the handlingof an aqueous WC-Co powder suspension.

    The WO3 surface layer on the oxidised tungsten carbidepowder dissolves at pH>3 with the tungsten concentrationincreasing linearly with time. Adding cobalt powder to thetungsten carbide suspension resulted in a significant reductionof the dissolution rate at pH<10. Electrokinetic studiesindicated that the reduced dissolution rate may be related tothe formation of surface complexes; the experiments showed thatCo species in solution adsorb on the oxidised tungsten carbidepowder.

    The surface forces of oxidised tungsten and cobalt surfaceswere investigated using the atomic force microscope (AFM)colloidal probe technique. The interactions at various ionicstrengths and pH values are well described by DLVO theory. Theadsorption of cobalt ions to tungsten oxide surfaces resultedin an additional non-DLVO force and a reduced absolute value ofthe surface potential. It was shown that the adsorption ofpoly(ethylene imine) (PEI) to the WO3 surfaces induces anelectrosteric repulsion.

    The properties of spray-dried WC-Co granules were related tothe WC primary particle size, and the poly(ethylene glycol)(PEG) binder and PEI dispersant content in aqueous WC-Cosuspensions. The granule characterisation includes a new methodfor measuring the density of single granules. The increase inthe fracture strength of granules produced from suspensionsthat were stabilised with PEI was related to a more densepacking of the WC-Co particles.

    The AFM was used to study the friction and adhesion ofsingle spray-dried WC-Co granules containing various amounts ofPEG binder. The adhesion and friction force between two singlegranules (intergranular friction) and between a granule and ahard metal substrate (die-wall friction) have been determinedas a function of relative humidity. The granule-wall frictionincreases with binder content and relative humidity, whereasthe granule-granule friction is essentially independent of therelative humidity and substantially lower than the granule-wallfriction at all PEG contents.

    Key words:Hard Metal, Cemented Carbide, WC-Co, TungstenCarbide, Cobalt, Oxidation, Dissolution, Surface Complexation,XPS, AFM, Colloidal Probe, Hamaker Constant, Cauchy, WO3,CoOOH, ESCA, Zeta-Potential, Surface Potential, Poly(ethyleneimine), PEI, Suspension, van der Waals, Steric, Spray-Dried,Poly(ethylene glycol), Strength, Density, Friction, Adhesion,Granule, PEG, Pressing, FFM.

  • 17. Ansebo, L.
    et al.
    Coracini, M. D. A.
    Bengtsson, M.
    Liblikas, Ilme
    KTH, Superseded Departments, Chemistry.
    Ramirez, M.
    KTH, Superseded Departments, Chemistry.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Tasin, M.
    Witzgall, P.
    Antennal and behavioural response of codling moth Cydia pomonella to plant volatiles2004In: Journal of applied entomology, ISSN 0931-2048, E-ISSN 1439-0418, Vol. 128, no 7, p. 488-493Article in journal (Refereed)
    Abstract [en]

    Identification of host volatile compounds attractive to codling moth Cydia pomonella, a most important insect of apple, will contribute to the development of safe control techniques. Synthetic apple volatiles in two doses were tested for antennal and behavioural activity in codling moth. Female antennae strongly responded to (Z)3-hexenol, (Z)3-hexenyl benzoate, (Z)3-hexenyl hexanoate, (+/-)-linalool and E,E-alpha-farnesene. Two other compounds eliciting a strong antennal response were the pear ester, ethyl (E,Z)-2,4-decadienoate, and its corresponding aldehyde, E,E-2,4-decadienal, which is a component of the larval defence secretion of the European apple sawfly. Attraction of codling moth to compounds eliciting a strong antennal response was tested in a wind tunnel. Male moths were best attracted to a blend of (E,E)-alpha-farnesene, (E)-beta-farnesene and ethyl (E,Z)-2,4-decadienoate. The aldehyde E,E-2,4-decadienal had an antagonistic effect when added to the above mixture.

  • 18. Arleth, L.
    et al.
    Bergström, Lars Magnus
    KTH, Superseded Departments, Chemistry.
    Pedersen, J. S.
    Small-angle neutron scattering study of the growth behavior, flexibility, and intermicellar interactions of wormlike SDS micelles in NaBr aqueous solutions2002In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, no 14, p. 5343-5353Article in journal (Refereed)
    Abstract [en]

    SDS wormlike micelles in water with NaBr are studied using small-angle neutron scattering. SDS concentrations ranging from 0.08 to 8.6 % vol in NaBr aqueous solutions at salinities from 0.6 to 1.0 M are covered. The scattering data are analyzed using a novel approach based on polymer theory and the results of Monte Carlo simulations. The method makes it possible to give a full interpretation of the scattering data, even for the entangled micellar solutions occurring at high concentrations and high salinities. Analysis of the scattering data at zero scattering angle demonstrates that the length of the micelles increases according to a power law as a function of concentration in the studied interval. The analysis furthermore shows that the length of the micelles increases exponentially with increasing salinity. The scattering data in the full range of scattering angles are analyzed using a model for polydisperse wormlike micelles where excluded volume effects are taken into account via an expression based on the polymer reference interaction site model (PRISM). This part of the analysis show that the micelles become more flexible as the salinity increases, which is due to an increased screening of the ionic micelles.

  • 19. Backman, A. C.
    et al.
    Bengtsson, M.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Liblikas, I.
    Witzgall, P.
    Volatiles from apple (Malus domestica) eliciting antennal responses in female codling moth Cydia pomonella (L.) (Lepidoptera: Tortricidae): Effect of plant injury and sampling technique2001In: Zeitschrift für Naturforschung C - A Journal of Biosciences, ISSN 0939-5075, E-ISSN 1865-7125, Vol. 56, no 04-mar, p. 262-268Article in journal (Refereed)
    Abstract [en]

    The antennal responses of codling moth females, Cydia pomonella, to volatiles from apple branches with green fruits were recorded by electroantennography coupled to gas chromatography. The antennae strongly responded to 4,8-dimethyl-1,3(E),7-nonatriene, linalool, beta -caryophyllene, (E)-beta -farnesene, germacrene D, (Z,E)-alpha -farnesene, (E,E)-alpha -farnesene and methyl salicylate. These compounds were all present in volatile collections on Porapak Q from both living and cut branches. Analysis by the solid phase microextraction technique (SPME) showed that the emission of some electrophysiologically active compounds increased after branches had been cut, especially 4,8-dimethyl-1,3(E),7-nonatriene, linalool and (E,E)-alpha -farnesene. The identification of apple volatiles eliciting antennal responses is the first step towards the identification of compounds mediating host-finding and oviposition in codling moth females.

  • 20. Baev, A.
    et al.
    Gelmukhanov, Faris
    KTH, Superseded Departments, Chemistry.
    Kimberg, Viktor
    KTH, Superseded Departments, Biotechnology.
    Ågren, Hans
    KTH, Superseded Departments, Biotechnology.
    Nonlinear propagation of strong multi-mode fields2003In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 36, p. 3761-3774Article in journal (Refereed)
    Abstract [en]

    We develop a strict theory of nonlinear propagation of few interacting stronglight beams. The key idea of our approach is a self-consistent solution ofthe nonlinear wave equation and the density matrix equations of the materialbeyond the rotatory wave approximation. We assume a Fourier expansion ofthe density matrixwhich goes beyond the conventionalTaylor expansions of thepolarization over the field amplitudeswhich is inadequate for the field strengthsthat we are interested in. Two qualitatively different situations are considered,with and without phase matching. Unlike in our previous paper (Baev et al2003 J. Opt. Soc. Am. B at press) devoted to the three-photon (TP) absorptioninduced upconverted lasing, we obtain here a strict solution for the nonlinearinteraction between different light beams. The general theory is applied to anumerical study of the role of saturation in TP photoabsorption by an organicchromophore in solution.

  • 21.
    Banerjee, Indradumna
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Salih, Tagrid
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Ramachandraiah, Harisha
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Erlandsson, Johan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, Superseded Departments (pre-2005), Chemistry.
    Araújo, A. C.
    Karlsson, M.
    Russom, Aman
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Slipdisc: A versatile sample preparation platform for point of care diagnostics2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 56, p. 35048-35054Article in journal (Refereed)
    Abstract [en]

    We report a microfluidic sample preparation platform called "Slipdisc" based on slipchip technology. Slipdisc is a rotational slipchip that uses a unique hand-wound clockwork mechanism for precise movement of specially fabricated polycarbonate discs. In operation, the microchannels and microchambers carved on the closely aligned microfluidic discs convert from continuous filled paths to defined compartments using the slip movement. The clockwork mechanism introduced here is characterised by a food dye experiment and a conventional HRP TMB reaction before measuring lactate dehydrogenase (LDH) enzyme levels, which is a crucial biomarker for neonatal diagnostics. The colorimetry based detection of LDH was performed with an unmodified camera and an image analysis procedure based on normalising images and observing changes in red channel intensity. The analysis showed a close to unity coefficient of determination (R2 = 0.96) in detecting the LDH concentration when compared with a standard Chemical Analyser, demonstrating the excellent performance of the slipdisc platform with colorimetric detection. The versatile point of care sample preparation platform should ideally be suited for a multitude of applications at resource-limited settings.

  • 22. Banyai, I.
    et al.
    Glaser, Julius
    KTH, Superseded Departments, Chemistry.
    Toth, I.
    Cyanide exchange on Tl(CN)(4)(-) in aqueous solution studied by Tl-205 and C-13 NMR spectroscopy2001In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 7, p. 1709-1717Article in journal (Refereed)
    Abstract [en]

    Dynamics of cyanide exchange between Tl((CN)-C-13)(4)(-) and (CN-)-C-13 was studied by means Tl-205 and C-13 NMR. The rate law consists of two parts: w = k(CN)[Tl(CN)(4)(-)][CN-] + k(OH)[Tl(CN)(4)(-)][CN-][OH-] with k(CN) = 9.7(+/-0.4) x 10(6) M(-1)s(-1) and k(OH) = 5.4(+/-0.4) x 10(10) M(-2)s(-1). It was shown that the exchange between the two cyano species can be studied, not only by C-13 NMR, but also by Tl-205 NMR using the heteronuclear carbon-thallium scalar coupling as an indicator, despite the fact that only one Tl site is present in the system. The reaction mechanism is discussed in terms of an associative interchange mechanism, I-A. Penetration of the incoming cyanide ion into the coordination sphere of Tl(CN)(4)(-) Tl(CN)(4)(OH)(-) is suggested to be the rate-determining step for the two parallel reactions paths. Possible reasons for the strong labilizing effect of the cyanide ligand is discussed in the light of thermodynamic and structural data. The possibility of detection of an exceptional exchange reaction, namely cyanide exchange between two Tl(CN)(4)(-) entities by a direct encounter was theoretically settled, but found to be too slow to be detected.

  • 23. Baranov, A. I.
    et al.
    Isaeva, A. A.
    Kloo, Lars A.
    KTH, Superseded Departments, Chemistry.
    Kulbachinskii, V. A.
    Lunin, R. A.
    Nikiforov, V. N.
    Popovkin, B. A.
    2D metal slabs in new nickel-tin chalcogenides Ni(7-delta)SnQ(2) (Q=Se, Te): average crystal and electronic structures, chemical bonding and physical properties2004In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 177, no 10, p. 3616-3625Article in journal (Refereed)
    Abstract [en]

    A systematic search for mixed low-valence, nickel-tin chalcogenides performed by establishing phase relations in the parts of Ni-Sn-Se and Ni-Sn-Te ternary systems resulted in the discovery of two new compounds, Ni5.62SnSe2 and Ni5.78SnTe2 Single crystals of both compounds were prepared by chemical transport with iodine and crystal structures were determined by single crystal X-ray investigation. The ED patterns for Ni5.78SnTe2 showed the presence of satellite reflections, which indicate a modulated structure with qapproximate to0.4a*. Average crystal structures of both compounds were determined to be of tetragonal symmetry (Sp.gr.I4/mmm, Z = 2) with a = 3.6890(8) Angstrom, c = 18.648(3) Angstrom, R-w = 0.0716 and a = 3.7680(5) Angstrom, c = 19.419(4) Angstrom, R-w, 0.0832, correspondingly, and are isostructural to known Ni5.72SbSe2 and Ni5.66SbTe2. Measurements were carried out for both compounds with respect to thermal, electrical and magnetic properties. Ab initio band structure calculations were also performed to take a first glance into the electronic structure of such type compounds. The anisotropy of their band structure was found. Physical property measurements showed both compounds to be the anisotropic metallic conductors and paramagnetics. Calculated difference charge density maps revealed pairwise covalent and multicenter metallic nature of the d-metal-chalcogen and d-metal-p-metal interactions, respectively.

  • 24. Baranov, A. I.
    et al.
    Isaeva, A. A.
    Kloo, Lars A.
    KTH, Superseded Departments, Chemistry.
    Popovkin, B. A.
    New metal-rich sulfides Ni6SnS2 and Ni9Sn2S2 with a 2D metal framework: Synthesis, crystal structure, and bonding2003In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 42, no 21, p. 6667-6672Article in journal (Refereed)
    Abstract [en]

    Two new, metal-rich nickel-tin sulfides Ni6SnS2 and Ni9Sn2S2 were found by establishing phase relations in the ternary Ni-Sn-S system at 540 degreesC. Their single crystals were prepared by means of chemical vapor transport reactions. Single crystal X-ray diffraction was used for the determination of their crystal structures. Both compounds crystallize in a tetragonal system (/4/mmm, No. 139, Z = 2, a = 3.646(1) Angstrom, c = 18.151(8) Angstrom for Ni6SnS2, and a = 3.678(1) Angstrom, c = 25.527(8) Angstrom for Ni9Sn2S2). Their crystal structures represent a new structure type and can be considered as assembled from bimetallic nickel-tin and nickel-sulfide slabs alternating along the crystallographic c axis. DFT band structure calculations showed the bonding within the bimetallic slabs to have a delocalized, multicenter nature, typical for metallic systems, and predominantly classical, pairwise bonding between nickel and sulfur.

  • 25. Baranov, A. I.
    et al.
    Kloo, Lars A.
    KTH, Superseded Departments, Chemistry.
    Olenev, A. V.
    Popovkin, B. A.
    Romanenko, A. I.
    Quasi-1D cations (1)(infinity) Ni8Bi8S (n+) of variable charge: Infinite columns (1)(infinity) Ni8Bi8S (2+) in the novel compound Ni(8)Bi(8)Sl(2)2003In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 42, no 13, p. 3988-3993Article in journal (Refereed)
    Abstract [en]

    The new compound Ni(8)Bi(8)Sl(2) has been synthesized and its crystal structure determined by X-ray crystallography. The structure contains one-dimensional (1D) cations (1)(infinity)[Ni8Bi8S](2+) separated by iodine anions. The geometry of the columns is similar to that of the recently reported (1)(infinity)[Ni8Bi8S](+), and the main difference between them is only their formal charge. Electronic structure calculations and physical properties measurements were performed to analyze the influence of the number of valence electrons on the bonding and properties of compounds containing these 1D cations. It was shown that the removal of one electron (i.e., (1)(infinity)[Ni8Bi8S](+) --> (1)(infinity)[Ni8Bi8S](2+)) mainly affects the Ni-S bonding within the cation and essentially has no influence on the intermetallic Ni-Bi bonding. It was found that Ni(8)Bi(8)Sl(2) containing double-charged columns has conductivity properties more similar to a pure 1D metal than the congener Ni(8)Bi(8)Sl containing mono-charged columns.

  • 26. Baranov, A. I.
    et al.
    Kloo, Lars A.
    KTH, Superseded Departments, Chemistry.
    Olenev, A. V.
    Popovkin, B. A.
    Romanenko, A. I.
    Shevelkov, A. V.
    Unique (infinity Ni8Bi8S)-Ni-1 metallic wires in a novel quasi-1D compound. Synthesis, crystal and electronic structure, and properties of Ni8Bi8SI2001In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 123, no 49, p. 12375-12379Article in journal (Refereed)
    Abstract [en]

    A new quasi-one-dimensional compound Ni8Bi8SI has been synthesized and its crystal structure determined from single-crystal X-ray diffraction data. The structure of Ni8Bi8SI consists of [(infinityNi8Bi8S)-Ni-1] columns separated by iodine atoms. Conductivity and magnetic susceptibility measurements (down to 4.2 K) show that Ni8Bi8SI is a one-dimensional metal and exhibits Pauli paramagnetic properties. These observations are in good agreement with the results from electronic structure calculations. An analysis of the chemical bonding employing difference electron charge density maps reveals strong multicenter Ni-Bi bonds and pair Ni-S interactions within the [(infinityNi8Bi8S)-Ni-1] columns. Only electrostatic interactions are inferred between the columns and iodine atoms.

  • 27.
    Bastardo Zambrano, Luis Alejandro
    et al.
    KTH, Superseded Departments, Chemistry.
    Claesson, Per Martin
    KTH, Superseded Departments, Chemistry.
    Brown, W.
    Department of Physical Chemistry, University of Uppsala,.
    Interactions between mucin and alkyl sodium sulfates in solution: a light scattering study2002In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, no 10, p. 3848-3853Article in journal (Refereed)
    Abstract [en]

    The properties of negatively charged mucin in aqueous solutions and its interaction with anionic sodium alkyl sulfates with different hydrocarbon chain lengths were studied by means of dynamic light scattering. It was observed that mucin forms aggregates in aqueous solutions with a hydrodynamic radius above 500 nm. These aggregates dissolve when sodium dodecyl sulfate or sodium decyl sulfate is present at sufficiently high concentration, above about 0.2 cmc (critical micellar concentration). On the other hand, sodium octyl sulfate is not very effective in dissolving the mucin aggregates. The hydrodynamic radius of the dissolved mucin, decorated with some associated surfactant, is found to be in the range of 40-90 nm. The observation that the dissolving power of the sodium alkyl sulfates decreases with decreasing surfactant chain length suggests that the association between the surfactant and mucin is hydrophobically driven. The kinetics of the dissolution process depends on the surfactant concentration, a higher surfactant concentration giving rise to a more rapid dissolution of the aggregates. It was also observed that when the ionic strength is increased, the surfactant concentration needed to dissolve the mucin aggregates decreases. This can be explained by reduction of repulsive electrostatic forces by the salt.

  • 28.
    Bastardo Zambrano, Luis Alejandro
    et al.
    KTH, Superseded Departments, Chemistry.
    Dedinaite, A.
    Unilever Res. Dvmt. Port Sunlight, Quarry Road East, Bebington, Wirral.
    Interactions between Mucin and Surfactants at Solid-Liquid Interfaces2002In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, no 24, p. 9383-9392Article in journal (Refereed)
    Abstract [en]

    The association between mucin and surfactants at the solid-liquid interface has been investigated employing reflectometry. The study is particularly aimed at understanding the removal of preadsorbed mucin layers by surfactant addition. To this end we investigated the effect of three different surfactants, one anionic surfactant, sodium dodecylsulfate (SDS), and two nonionic ones, penta(oxy ethylene) dodecyl ether (C12E5) and n-dodecyl beta-D-maltopyranoside (C-12-mal), All three surfactants were found to be potent in removing mucin from hydrophobic surfaces. On the otherhand, C-12-mal was found to have a very limited effect on mucin adsorbed to hydrophilic negatively charged surfaces, whereas the mucin layer was removed by SDS and C12E5. The association between mucin and the three different surfactants was also investigated by means of dynamic light scattering and surface tension measurements. It was concluded that SDS associates readily with mucin above a critical surfactant concentration, about 0.2 cmc, whereas the nonionic surfactants associate with mucin to a very limited degree. The results obtained with the different techniques allow us to propose that C12E5 removes mucin from silica surfaces by competitive adsorption, whereas the removal of mucin by SDS is due to formation of mucin/SDS complexes that have reduced surface affinity and increased water solubility compared to mucin alone.

  • 29.
    Belda de Lama, Oscar
    KTH, Superseded Departments, Chemistry.
    Bispyridylamides as ligands in asymmetric catalysis2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis deals with the preparation and use of chiralbispyridylamides as ligands in metal-catalyzed asymmetricreactions.

    The compounds were prepared by amide formation usingdifferent coupling reagents. Bispyridylamides havingsubstituents in the 4- or 6- positions of the pyridine ringswere prepared by functional group interconversion of the 4- or6- halopyridine derivatives. These synthetic approaches provedto be useful for various types of chiral backbones. Pseudo C2-symmetric bispyridylamides were also synthesizedby means of stepwise amide formation.

    The compounds were used as ligands in themicrowave-accelerated Mocatalyzed asymmetric allylic alkylationreaction. Ligands having ð-donating substituents in the4-positions of the pyridine rings gave rise to products withhigher branched to linear ratio. The catalytic reaction, whichproved to be rather general for allylic carbonates with anaromatic substituent, was used as the key step in thepreparation of (R)-baclofen. The Mo-bispyridylamide catalystprecursor was studied by NMR spectroscopy.

    Bispyridylamide complexes of metal alkoxides were alsoevaluated in the asymmetric addition of cyanide to aldehydesand the metal complexes involved were studied by NMRspectroscopy and X-ray crystallography. Chiral diamines wereused as additives to study the ring opening of cyclohexeneoxide with azide, catalyzed by Zr(IV)-bispyridylamidecomplexes.

    Various bispyridylamides were attached to solid supports oforganic or inorganic nature. The solid-supported ligands wereused in Mo-catalyzed asymmetric allylic alkylation reactionsand in the asymmetric addition of cyanide to benzaldehyde.

    Keywords:asymmetric catalysis, chiral ligand, pyridine,amide, allylic alkylation, enantioselective, cyanation,ring-opening, chiral Lewis acid.

  • 30. Belda, O.
    et al.
    Kaiser, N. F.
    Bremberg, U.
    Larhed, M.
    Hallberg, A.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Highly stereo- and regioselective allylations catalyzed by Mo-pyridylamide complexes: Electronic and steric effects of the ligand2000In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 65, no 18, p. 5868-5870Article in journal (Refereed)
  • 31. Belda, O.
    et al.
    Lundgren, S.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Recoverable resin-supported pyridylamide ligand for microwave-accelerated molybdenum-catalyzed asymmetric allylic alkylations: Synthesis of baclofen2003In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 5, no 13, p. 2275-2278Article in journal (Refereed)
    Abstract [en]

    The syntheses of a series of 4-monosubstituted pyridylamides and a resin-supported pyridylamide are described. The ligands were evaluated in the microwave-accelerated molybdenum-catalyzed asymmetric allylic alkylation. The reaction afforded the product in high yield and with high regio- and enantioselectivity. The heterogeneous ligand could be reused several times with no change in the reaction outcome. The asymmetric allylic alkylation was employed as the key step in the enantioselective synthesis of (R)-baclofen.

  • 32. Belda, O.
    et al.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Substituted pyridylamide ligands in microwave-accelerated Mo(0)-catalysed allylic alkylations2002In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, no 11, p. 1601-1606Article in journal (Refereed)
    Abstract [en]

    Novel 4- and 6-substituted bis-pyridylamides were prepared by microwave accelerated nucleophilic substitution of the 4-and 6-halo substituted derivatives of the parent ligand la. The ligands were used in the asymmetric allylation of cinnamyl carbonate catalysed by Mo(0) in which the 4-chloro- and 4-pyrrolidyl substituted ligand derivatives exhibited high regioselectivity (74:1 and 88:1. respectively) and enantioselectivity (96% ee), whereas 6-substituted ligands afforded no product under the same conditions. Other allylic substrates were used to explore the generality of the procedure.

  • 33.
    Belda, Oscar
    et al.
    KTH, Superseded Departments, Chemistry.
    Duquesne, Sophie
    KTH, Superseded Departments, Chemistry.
    Fischer, A.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Chiral bispyridylamide metal complexes as catalysts for the enantioselective adddition of TMSCN to aldehydes2004In: Journal of Organometallic Chemistry, ISSN 0022-328X, E-ISSN 1872-8561, Vol. 689, no 23, p. 3750-3755Article in journal (Refereed)
    Abstract [en]

    The use of (1R,2R)-N,N'-bis(2-pyridinecarboxyamido)-1,2-diphenylethane metal complexes as catalysts for the enantioselective addition of trimethylsilyl cyanide to aldehydes is described. Enantioselectivities up to 70% ee were obtained with a Ti(IV) catalyst. Complexes with Zr(IV), Sc(III), Yb(III) and Cu(II) afforded less selective catalysts. For the Zr(IV) complex, a rate and selectivity enhancement was observed when adding 0.5 equiv. of water with respect to the catalyst. Studies of the metal complexes involved in the reaction were carried out by means of H-1 NMR spectroscopy. A Zr complex was shown by X-ray crystallography to exhibit distorted octahedral coordination, with the four nitrogen atoms of the doubly deprotonated ligand essentially in one plane.

  • 34.
    Belda, Oscar
    et al.
    KTH, Superseded Departments, Chemistry.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Molybdenum-catalyzed asymmetric allylic alkylations2004In: Accounts of Chemical Research, ISSN 0001-4842, E-ISSN 1520-4898, Vol. 37, no 3, p. 159-167Article in journal (Refereed)
    Abstract [en]

    The highly regio- and enantioselective molybdenum-catalyzed allylic alkylation reaction has become a powerful synthetic tool during the past few years. This Account describes the achievements gained so far in the area, with special attention directed to the different chiral ligands that have been used for inducing chirality in the products, the range of allylic substrates and nucleophiles employed, mechanistic studies, and applications of the reaction in asymmetric syntheses.

  • 35. Bengtsson, M.
    et al.
    Backman, A. C.
    Liblikas, I.
    Ramirez, M. I.
    Borg-Karlson, Anna-Karin
    KTH, Superseded Departments, Chemistry.
    Ansebo, L.
    Anderson, P.
    Lofqvist, J.
    Witzgall, P.
    Plant odor analysis of apple: Antennal response of codling moth females to apple volatiles during phenological development2001In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 49, no 8, p. 3736-3741Article in journal (Refereed)
    Abstract [en]

    Volatile compounds were collected from apple branches (Malus domestica) at different developmental stages, and the antennal response of codling moth females (Cydia pomonella) to these compounds was recorded by electroantennography coupled to gas chromatography. Presence of a range of terpenoid compounds, many of which had antennal activity, was characteristic for volatile collections from branches with leaves, and from small green apples. Nine compounds from branches with leaves and green fruit consistently elicited an antennal response: methyl salicylate, (E)-beta -farnesene, fi-caryophyllene, 4,8-dimethyl-1,3(E),7-nonatriene, (Z)3-hexenol, (Z,E)-alpha -farnesene, linalool, germacrene D, and (EE)-alpha -farnesene. The bouquet emitted from flowering branches contained in addition several benzenoid compounds which were not found after bloom. Small green apples, which are the main target of codling moth oviposition during the first seasonal flight period, released very few esters. In comparison, fully grown apples released a large number of esters, but fewer terpenoids. The study of apple volatiles eliciting an antennal response, together with a survey of the seasonal change in the release of these compounds, is the first step toward the identification of volatiles mediating host-finding and oviposition in codling moth females.

  • 36.
    Benkestock, Kurt
    et al.
    KTH, Superseded Departments, Chemistry.
    Edlund, Per Olof
    Biovitrum AB, Analyt Sci.
    Roeraade, Johan
    KTH, Superseded Departments, Chemistry.
    On-line microdialysis for enhanced resolution and sensitivity during electrospray mass spectrometry of non-covalent complexes and competitive binding studies2002In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 16, no 21, p. 2054-2059Article in journal (Refereed)
    Abstract [en]

    Many proteins and macromolecules easily form metal adduct ions which impairs their analysis by mass spectrometry. The present study describes how the formation of undesired adducts can be minimized by on-line microdialysis for non-covalent binding studies of macromolecules with low molecular mass ligands with electrospray ionization mass spectrometry (ESI-MS). The technique was indispensable for protein-ligand studies due to reduction of unwanted adduct ions, and thus gave excellent resolution and a sensitivity improvement of at least 5 times. The core of the analytical system was a modified microdialysis device, which was operated in countercurrent mode. A novel technique based on microdialysis for competitive binding studies is also presented. The noncovalent complex between a protein and a ligand was formed in the sample vial prior to analysis. The complex was injected into an on-line microdialysis system where a competitive ligand was administered in the dialysis buffer outside of the fiber. The second ligand competitively displaced the first ligand through transport via the wall of the dialysis fiber, and the intact complexes were detected by ESI-MS.

  • 37.
    Benkestock, Kurt
    et al.
    KTH, Superseded Departments, Chemistry.
    Sundqvist, Gustav
    KTH, Superseded Departments, Chemistry.
    Edlund, Per Olof
    Biovitrum AB, Dept Analyt Sci.
    Roeraade, Johan
    KTH, Superseded Departments, Chemistry.
    Influence of droplet size, capillary-cone distance and selected instrumental parameters for the analysis of noncovalent protein-ligand complexes by nano-electrospray ionization mass spectrometry2004In: Journal of Mass Spectrometry, ISSN 1076-5174, E-ISSN 1096-9888, Vol. 39, no 9, p. 1059-1067Article in journal (Refereed)
    Abstract [en]

    It has been suggested in the literature that nano-electrospray ionization (nano-ESI) mass spectrometry better reflects the equilibrium between complex and free protein in solution than pneumatically assisted electrospray ionization (ESI) in noncovalent interaction studies. However, no systematic studies of the effects of ionization conditions have been performed to support this statement. In the present work, different instrumental and sample-derived parameters affecting the stability of noncovalent complexes during analysis by nano-ESI were investigated. In general, increased values of parameters such as drying gas flow-rate, ion-source temperature, capillary tip voltage and buffer concentration lead to a dissociation of ribonuclease A (RNAse)-cytidine 2'-monophosphate (CMP) and cytidine 5'-triphosphate (CTP) complexes. The size of the electrosprayed droplets was shown to be an important issue. Increasing the capillary to cone distance yielded an increased complex to free protein ratio when a hydrophilic ligand was present and the reverse effect was obtained with a hydrophobic ligand. Important in this regard is the degree of sampling of ions originating from late-generation residue droplets, that is, ions present in the droplet bulk. Sampling of these ions increases with longer capillary-cone distance (flight time). Furthermore, when the sample flow-rate was increased by increasing the capillary internal tip i.d. from 4 to 30 mum, a decreased complex to free protein ratio for the RNAse-CTP system was observed. This behavior was consistent with the change in surface to volume ratio for flow-rates between 2 and 100 nl min(-1). Finally, polarity switching between positive and negative ion modes gave a higher complex to free protein ratio when the ligand and the protein had the same polarity.

  • 38.
    Benkestock, Kurt
    et al.
    KTH, Superseded Departments, Chemistry.
    Van Pelt, C. K.
    Advion BioSci Inc, Ithaca, NY USA.
    Åkerud, T.
    Lund Univ, Dept Biophys Chem.
    Sterling, A.
    Advion BioSci Ltd, Norwich, Norfolk England.
    Edlund, Per Olof
    Biovitrum AB, Analyt Sci.
    Roeraade, Johan
    KTH, Superseded Departments, Chemistry.
    Automated Nano-Electrospray Mass Spectrometry for Protein-Ligand Screening by Noncovalent Interaction Applied to Human H-FABP and A-FABP2003In: Journal of Biomolecular Screening, ISSN 1087-0571, E-ISSN 1552-454X, Vol. 8, no 3, p. 247-256Article in journal (Refereed)
    Abstract [en]

    A method for ligand screening by automated nano-electrospray ionization mass spectrometry (nano-ESI/MS) is described. The core of the system consisted of a chip-based platform for automated sample delivery from a 96-well plate and subsequent analysis based on noncovalent interactions. Human fatty acid binding protein, H-FABP (heart) and A-FABP (adipose), with small potential ligands was analyzed. The technique has been compared with a previously reported method based on nuclear magnetic resonance (NMR), and excellent correlation with the found hits was obtained. In the current MS screening method, the cycle time per sample was 1.1 min, which is approximately 50 times faster than NMR for single compounds and approximately 5 times faster for compound mixtures. High reproducibility was achieved, and the protein consumption was in the range of 88 to 100 picomoles per sample. Furthermore, a novel protocol for preparation of A-FABP without the natural ligand is presented. The described screening approach is suitable for ligand screening very early in the drug discovery process before conventional high-throughput screens (HTS) are developed and/or used as a secondary screening for ligands identified by HTS.

  • 39.
    Berg, Astrid
    KTH, Superseded Departments, Chemistry.
    The response of soil weathering to climate change1997Doctoral thesis, comprehensive summary (Other scientific)
  • 40. Berg, I. C. H.
    et al.
    Rutland, Mark W
    KTH, Superseded Departments, Chemistry.
    Arnebrant, T.
    Lubricating properties of the initial salivary pellicle - an AFM Study2003In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 19, no 6, p. 365-369Article in journal (Refereed)
    Abstract [en]

    The role of saliva in the oral cavity is manifold; an important function is to serve as lubricant between hard (enamel) and soft (mucosal) tissues. Intraoral lubrication is of crucial importance in order to maintain functions such as deglutition, mastication and the faculty of speech. A large number of people suffer from impaired salivary functions, displaying symptoms such as 'dry mouth'. This results in a need for methods to assess the lubricating properties of both native saliva and potential artificial saliva formulations. Here, normal as well as lateral forces, acting between adsorbed salivary films, have been measured for the first time by means of colloidal probe atomic force microscopy (AFM). It was found that the presence of salivary pellicles between hard surfaces reduces the friction coefficient by a factor of 20. This reduction of friction is consistent with the long-range purely repulsive nature of the normal forces acting between the salivary films. The lubricating mechanism is presumably based on a full separation of the sliding surfaces by the salivary films. The friction between salivary films has been investigated at normal loads that cover the clinical jaw closing forces, and it can be concluded that the lubricating properties are maintained within this load interval. The present study indicates the usefulness of colloidal probe AFM, which offers a direct and quantitative measure of lubrication at a molecular level, in the study of biotribological phenomena. In particular, the results obtained here may have implications for the development of saliva substitutes.

  • 41.
    Berg, Katja E.
    KTH, Superseded Departments, Chemistry.
    Bimetallic model compounds for artificial photosynthesis1997Doctoral thesis, comprehensive summary (Other scientific)
  • 42.
    Bergelin, Anette
    KTH, Superseded Departments, Chemistry.
    The acid-base properties and aggregation of humic materials2001Doctoral thesis, comprehensive summary (Other scientific)
  • 43.
    Bergelin, Anette
    KTH, Superseded Departments, Chemistry.
    The protonation and aggregation of humic material in natural waters: an experimental study1998Licentiate thesis, comprehensive summary (Other scientific)
  • 44. Bergeron, V.
    et al.
    Claesson, Per M.
    KTH, Superseded Departments, Chemistry.
    Structural forces reflecting polyelectrolyte organization from bulk solutions and within surface complexes2002In: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 96, no 03-jan, p. 1-20Article in journal (Refereed)
    Abstract [en]

    The interactions between two macroscopic surfaces approaching one another underlies many of the phenomena observed in Colloid and Interface science. In Russia this gave rise to the branch of colloid science now referred to as Surface Forces. Important discoveries, such as the molecular organization of solvent molecules at an interface, have been unveiled by surface force measurements. More recently, forces and structures at macromolecular length scales have been uncovered. In particular, oscillatory force profiles have been detected from aqueous solutions containing polyelectrolytes. The force-structure relationship can reflect organization in the bulk solution or the internal structure of the adsorbed layer. Using a range of surface force techniques, combined with X-ray and neutron scattering results, we review the main features of these fascinating systems and provide an overview of how they relate to other systems such as micellar solutions, polymer-surfactant complexes and simple solvents.

  • 45.
    Berglund, Per
    KTH, Superseded Departments, Chemistry.
    Candida rugosa lipase as a catalyst in organic media: Enantioselectivity in kinetic resolutions of 2-methylalkanoic acids1995Doctoral thesis, comprehensive summary (Other academic)
  • 46.
    Bergström, Lars Magnus
    KTH, Superseded Departments, Chemistry.
    Derivation of expressions for the spontaneous curvature, mean and Gaussian bending constants of thermodynamically open surfactant monolayers and bilayers2003In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 118, no 3, p. 1440-1452Article in journal (Refereed)
    Abstract [en]

    We have derived expressions for the spontaneous curvature H-0, the mean and Gaussian bending constants, k(c) and (k) over bar (c), respectively, for a surfactant film of finite thickness that is open in a thermodynamic sense. Geometrical packing constraints are taken into account and give rise to explicit large and important contributions to k(c), (k) over bar (c), and k(c)H(0). From its contribution to the latter quantity we may deduce that surfactant aggregates (micelles, vesicles, microemulsion droplets) are expected to dramatically increase their size with increasing surfactant tail length. Moreover, the coupling between free energy contributions related to surfactant head group and tail with geometrical packing constraints give rise to dominant terms on the form 2xi(p)H(0), where xi(p) is the thickness of a planar film, in the expressions for k(c). In the case of repulsive head group effects that favor a large spontaneous curvature, such as electrostatics, these terms raise k(c) and thus increase the rigidity of the film. Due to the constraint of constant free monomer chemical potentials, the composition of the film becomes a function of curvature. As a result, the ability of a surfactant film to have different surfactant compositions in differently curved parts (e.g., inner and outer layer of a vesicle, central parts and end caps of rod or threadlike micelles, etc.) may considerably reduce k(c), whereas (k) over bar

  • 47.
    Bergström, Lars Magnus
    KTH, Superseded Departments, Chemistry.
    Molecular interpretation of the mean bending constant for a thermodynamically open vesicle bilayer2001In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 24, p. 7675-7686Article in journal (Refereed)
    Abstract [en]

    Expressions for the various molecular contributions to the mean bending constant k(c) of a thermodynamically open vesicle bilayer have been derived, from which k(c) maybe calculated from an appropriate molecular-thermodynamic model as a function of the structure of the surfactants making up the aggregates as well as the solution state. It is demonstrated that k(c) determines the shape of a vesicle bilayer insofar as spherical vesicles form when k(c) is large and positive! whereas nonspherical. vesicles predominate at values of k(c) close to or below zero. It is found that contributions due to electrostatics and residual headgroup effects, which are present for one-component as well as mixed aggregates, mainly give rise to a positive value of k(c) whereas geometrical packing constraints are less important. However, the mixing of two or more surfactants can significantly reduce k(c) to values where nonspherical vesicles may begin to form. The magnitude of the reduction of k(c) due to mixing increases with increasing asymmetry with respect to headgroup cross-section area, charge number, and hydrocarbon tail volume between two surfactants in a binary surfactant mixture. The asymmetry is most pronounced for a binary mixture where the surfactant that carries the charge has the larger headgroup and the smaller tail. The reduction of k(c) due to mixing is, however, expected to be less than the corresponding effect for the bilayer bending constant of a spherical vesicle as a result of an additional positive contribution in the expression for the compositional contribution to k(c).

  • 48.
    Bergström, Lars Magnus
    KTH, Superseded Departments, Chemistry.
    Synergistic effects in mixtures of an anionic and a cationic surfactant2001In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 4, p. 993-998Article in journal (Refereed)
    Abstract [en]

    Synergistic effects in mixtures of an anionic and a cationic surfactant have been theoretically investigated. We derive an explicit expression far the critical micelle concentration (cmc) as a function of the aggregate composition from the Poisson-Boltzmann mean field theory and, thus, demonstrate that the conspicuously large synergistic effects that have been experimentally observed can be rationalized without the need of invoking any specific interactions between the surfactant headgroups. The simple relation beta = -4 epsilon (el/kTelNzT) is derived, i.e.,the interaction parameter beta is directly related to the electrostatic free energy contribution epsilon (el) for the pure surfactant, implying, among other things, that the magnitude of beta decreases vith increasing cmc for the pure surfactant in agreement with experimental observations. We furthermore demonstrate that the aggregate composition is close to equimolar composition (x(1) = 0.5) at cmc in almost the entire regime of overall surfactant compositions and that the free monomer concentration of the surfactant in excess is generally much larger than the corresponding quantity for the surfactant in deficit.

  • 49.
    Bergström, Lars Magnus
    KTH, Superseded Departments, Chemistry.
    Thermodynamics of anisotropic surfactant micelles. I. The influence of curvature free energy on the micellar size and shape2000In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 113, no 13, p. 5559-5568Article in journal (Refereed)
    Abstract [en]

    A novel theory for the structural behavior of surfactant micelles is expounded. The micelles are considered to be generally shaped as triaxial tablets with distinct thickness width and length, respectively, and may become spherical, spherocylindrical or disk-shaped in the special cases where two or more of the dimensions are equal. It is demonstrated that the average width and length of a tablet-shaped micelle with a fixed thickness is mainly determined by two constants, k(1) and k(2), related to the first and second order correction in curvature of the micellar end caps. The size of the micelles is found to be mainly determined by k(1), whereas k(2) influences the shape, i.e., the length-to-width ratio, of the micelles so that the micellar size increases with increasing k(1) and the length-to-width ratio decreases with increasing k(2). Hence, large positive values of k(2) promote the formation of tablets rather than very long spherocylinders. An additional parameter related to the curvature of the straight cylindrical rims may influence the structure of the tablet-shaped micelles insofar k(2) is close to or below zero.

  • 50.
    Bergström, Lars Magnus
    KTH, Superseded Departments, Chemistry.
    Thermodynamics of anisotropic surfactant micelles. II. A molecular interpretation of the micellar curvature free energy2000In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 113, no 13, p. 5569-+Article in journal (Refereed)
    Abstract [en]

    Explicit expressions have been derived for the two curvature constants k(1) and k(2) that mainly influence the size and shape, respectively, of generally shaped micelles (triaxial tablets with a thickness < width < length). It is found that geometrical packing constraints, together with an unfavorable hydrocarbon/water interfacial tension gamma(hc/w), give rise to a large and positive contribution to both k(1) and k(2) that increases with the micellar thickness (equivalent to surfactant tail length) as well as with gamma(hc/w). The constant k(1) that mainly influence the size of the micelles may be brought down by electrostatics to values where rather small micelles are able to form. However, electrostatics also have a tendency to increase the constant k(2) that mainly affects the length-to-width ratio of the micelles so that the smaller micelles are predicted to be rather disklike, i.e., with a low length-to-width ratio. In addition, residual head group effects as well as the free energy contribution due to the hydrocarbon chains may influence the micellar size and shape. In particular, it is demonstrated that mixing of two surfactants reduces k(2) and promotes the formation of elongated micelles with a large length-to-width ratio whereas k(1), and thus the overall size of the micelles, is only slightly influenced. The effect of mixing is predicted to increase with increasing asymmetry between the surfactants mixed in the micelles with respect to head group size and charge number as well as hydrophobic tail volume.

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