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  • 151.
    Bratt K, Sunnerheim K., Nordenhem H., Nordlander G., Långström B.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Pine Weevil (Hylobius abietis) Antifeedants from Lodgepole Pine (Pinus contorta)2001Article in journal (Other scientific)
  • 152.
    Bratt, Katharina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Secondary plant metabolites as defence against herbivores and oxidative stress: Synthesis, isolation and biological evaluation2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis the isolation, synthesis and biological evaluation of natural defense compounds against herbivores or oxidative stress is discussed.

    The first part concerns the metabolites of platyphylloside ((5S)-5-hydroxy-1,7-bis-(4-hydroxyphenyl)-3-heptanone-5-O-β-D-glucopyranoside), a phenolic glucoside found in birch (Betula pendula) that possess digestibility inhibiting activity in herbivores. The structure-activity relationship of platyphylloside analogues were investigated regarding to stereochemistry and substitution pattern on the aromatic rings. The metabolites formed in vitro in rumen fluid were synthesized and the active metabolite determined as (R)-centrolobol (1,7-bis-(4-hydroxyphenyl)-3-heptanol). Treatment of mice and rats with rac-centrolobol did not effect either food intake or body weight. Effect of platyphylloside in moose was also investigated, and the results indicate that there was an in vivo digestibility reducing activity.

    The second part concerns naturally occurring antioxidants. Avenanthramides is a class of phenolic antioxidants found in oat (Avena sativa). Avenanthramides derived from either anthranilic acid or 5-hydroxyanthranilic acid were evaluated for their antioxidative capacity and quantified in oat extracts. Avenanthramides derived from 5-hydroxyanthranilic acid possessed higher activity than those from anthranilic acid. The order of reactivity depending on substitution pattern on the phenolic moiety was found to be 4-hydroxy < 4-hydroxy-3-methoxy < 3,5-dimethoxy-4-hydroxy and 3,4-dihydroxy. A synthesis towards antioxidative compounds such as 4-deoxycarbazomycin was developed.

    The third part concerns the isolation of compounds from Lodgepole pine (Pinus contorta) with antifeedant activity against pine weevil (Hylobius abietis). Two compounds possessing high activity were isolated and identified.

  • 153.
    Braunschweig, F.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Sörensen, J.
    von Bibra, H.
    Olsson, A.
    Ryden, L.
    Långström, B.
    Linde, C.
    Effects of long-term biventricular pacing on myocardial blood flow and oxygen consumption. A study using 11C-acetate-PET2003In: Am. J. Cardiol., Vol. 92, no 425, p. 95-99Article in journal (Refereed)
  • 154. Bregadze, V I.
    et al.
    Sivaev, I.
    Bruskin, A.
    Sjöberg, S.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Nesterov, V.
    Antipin, M.
    Synthesis of Schiff bases and monoalkylamino derivatives of closododecaborae(2-) anion2000In: Contemporary Boron ChemistryArticle in journal (Other scientific)
  • 155.
    Bregadze V, Sivaev I, Sjöberg S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Synthesis of Functional Derivatives of Cobalt Bis(1,2-dicarolide) Anion for BNCT.2002In: Research and Development in Neutron Capture Therapy, p. 13-17Article in journal (Other scientific)
  • 156.
    Brink, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Mollerstedt, H
    Ottosson, CH
    Characteristics of the electronic structures of diabatically and adiabatically Z/E-isomerizing olefins in the T-1 state2001In: JOURNAL OF PHYSICAL CHEMISTRY A, ISSN 1089-5639, Vol. 105, no 16, p. 4071-4083Article in journal (Refereed)
    Abstract [en]

    Nonlocal gradient-corrected and hybrid density functional theory (DFT) have been used to calculate T1 potential energy surfaces (PES), spin densities, and geometries of ethylene and aromatic olefins of various sizes: ethylene (1), styrene (2), stilbene (3

  • 157.
    Broadbent, JK
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Martincigh, BS
    Raynor, MW
    Salter, LF
    Moulder, R
    Sjoberg, P
    Markides, KE
    Capillary supercritical fluid chromatography combined with atmospheric pressure chemical ionisation mass spectrometry for the investigation of photoproduct formation in the sunscreen absorber 2-ethylhexyl-p-methoxycinnamate1996In: JOURNAL OF CHROMATOGRAPHY A, ISSN 0021-9673, Vol. 732, no 1, p. 101-110Article in journal (Refereed)
    Abstract [en]

    The photoproducts formed on ultraviolet irradiation of the sunscreen absorber trans-2-ethylhexyl-p-methoxycinnamate, were separated and characterised using a new combined technique, capillary supercritical fluid chromatography-atmospheric pressure chemic

  • 158.
    Broddefalk, A
    et al.
    INORGANIC CHEMISTRY. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    James, P
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Liu, HP
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Kalska, B
    Andersson, Y
    Granberg, P
    Nordblad, P
    Haggstrom, L
    Eriksson, I
    Structural and magnetic properties of (Fe1-xMnx)3P (x < 0.25)2000In: PHYSICAL REVIEW B, ISSN 1098-0121, Vol. 61, no 1, p. 413-421Article in journal (Refereed)
    Abstract [en]

    Structural and magnetic properties of (Fe1-xMnx)(3)P compounds have been investigated by means of x-ray and neutron diffraction experiments, magnetization measurements, Mossbauer experiments, and first principles calculations. The Curie temperature of the

  • 159.
    Bruskin, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Sivaev, Igor
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Persson, Mikael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Lundqvist, Hans
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Carlsson, Jörgen
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Sjöberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Radiobromination of monoclonal antibody using potassium [76Br] (4 isothiocyanatobenzyl-ammonio)-bromo-decahydro-closo-dodecaborate (Bromo-DABI)2004In: Nuclear Medicine and Biology, ISSN 0969-8051, E-ISSN 1872-9614, Vol. 31, no 2, p. 205-11Article in journal (Refereed)
    Abstract [en]

    The use of charged linkers in attaching radiohalogens to tumor-seeking biomolecules may improve intracellular retention of the radioactive label after internalization and degradation of targeting proteins. Derivatives of polyhedral boron clusters, such as closo-dodecaborate (2-) anion, might be possible charged linkers. In this study, a bifunctional derivative of closo-dodecaborate, (4-isothiocyanatobenzyl-ammonio)-undecahydro-closo-dodecaborate (DABI) was labeled with positron-emitting nuclide (76)Br (T 1/2 = 16.2 h) and coupled to anti-HER2/neu humanized antibody Trastuzumab. The overall labeling yield at optimized conditions was 80.7 +/- 0.6%. The label was proven to be stable in vitro in physiological and a set of denaturing conditions. The labeled antibody retained its capacity to bind to HER-2/neu antigen expressing cells. The results of the study demonstrated feasibility for using derivatives of closo-dodecaborate in indirect labeling of antibodies for radioimmunoPET.

  • 160.
    Bucur, R.V.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Organisk kemi.
    Berger, R
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Electrochemical measurements in aqueous solution of the solid-state diffusion of Cu+ in various binary and ternary copper sulphides1996In: Baltic conference on interfacial electrochemistry (Extended abstracts): Tartu, Juni 14-18, 1996, 1996, p. 49-50Conference paper (Other (popular scientific, debate etc.))
    Abstract [en]

    While solid-state diffusion is in general a slow process, exceptions are found in certain kinds of inorganic materials, predominantly concerning small cations moving in an environment of large and chemically soft anions. [...] We have used a potentiometric method, recording the change in potential after a perturbing current pulse and have studied three sulphides under the [radioactive waste] repositary conditions, namely chalcocite, chalcopyrite and bornite

  • 161.
    BUCUR, RV
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    BERGER, R
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    ELECTROCHEMICAL POTENTIOMETRIC DETERMINATION OF THE DIFFUSION-COEFFICIENT OF COPPER IN LOW DIGENITE, A COPPER SULFIDE1995In: Solid State IonicsArticle in journal (Refereed)
    Abstract [en]

    The diffusion of copper in ''low digenite'', Cu1.8S, has been measured by an electrochemical potentiometric method within the temperature range 15-50 degrees C. At 25 degrees C the chemical diffusion coefficient ($) over tilde D is 1.8(1) x 10(-8) cm(2)/

  • 162.
    Buttner, Frank
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Norgren, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Zhang, Suode
    Prabpai, Samran
    Kongsaeree, Palangpon
    Arvidsson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Cyclic B-Tetra- and Pentapeptides: Synthesis through On-Resin Cyclization and Confomrational Studies by X-Ray, NMR and CD Spectroscopy and Theoretical Calculations2005In: Chem. Eur. J., Vol. 11, p. 6145-6158Article in journal (Refereed)
    Abstract [en]

    The solution-phase synthesis of the simplest cyclic B-tetrapeptide, cyclo(B-Ala)4 (4), as well as the solidphase syntheses through side chain anchoring and on-resin cyclization of the cyclic B3-tetrapeptide cyclo-(B3hPhe-B3hLeu-B3hLys-B3hGln-) (14) and the first cyclic B3-pentapeptide cyclo- (B3hVal-B3hPhe-B3Leu- B3hLys-B3hLys-) (19) are reported. Extensive computational as well as spectroscopic studies, including X-ray and NMR spectroscopy, were undertaken to determine the preferred conformations of these unnatural oligomers in solution and in the solid state. cyclo(B-Ala)4 (4) with no chiral side chains is shown to exist as a mixture of rapidly interchanging conformers in solution, whereas inclusion of chiral side chains in the cyclo-B3-tetrapetpride causes stabilizaton of one dominating conformer. The cyclic B3-pentapeptide on the other hand shows larger conformational freedom. The X-ray structure of achiral cyclo(B-Ala)4 (4) displays a Ci-symmetrical 16-membered ring with adjacent C=O and N-H atoms pointing pair wise up and down with respect to the ring plane. CD spectorscopic examinations of all cyclic B-peptides were undertaken and revealed results valuable as starting point for further structural investigations of these entities.

  • 163.
    Bylund, D.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Danielsson, R.
    Malmquist, G.
    Markides, K.E.
    Chromatographic alignment by warping and dynamic programming as a pre-processing tool for PARAFAC modelling of liquid chromatography - mass spectrometry data2002In: J. of Chromatography A, no 961, p. 237-244Article in journal (Refereed)
  • 164.
    Bylund, D
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Danielsson, R
    Markides, KE
    Peak purity assessment in liquid chromatography-mass spectrometry2001In: JOURNAL OF CHROMATOGRAPHY A, ISSN 0021-9673, Vol. 915, no 1-2, p. 43-52Article in journal (Refereed)
    Abstract [en]

    Fixed-size moving window evolving factor analysis and base peak chromatograms have been used for peak purity detection in data generated with LC-MS. The two methods were evaluated with both real and simulated data and were found to be fast and complementa

  • 165.
    Bylund, D.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Samskog, J.
    Jacobsson, S.P.
    Markides, K.E.
    Classification of Lactate Dehydrogenase of Different Origin by Liquid Chromatography-Mass Spectrometry and Multivariate Analysis2003In: J. Am. Soc. Mass Spectrom., no 14, p. 236-240Article in journal (Refereed)
  • 166.
    Bylund, Dan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Chemometric Tools for Enhanced Performance in Liquid Chromatography-Mass Spectrometry2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Liquid chromatography-mass spectrometry (LC-MS) has become an important analytical on-line technique, capable of producing large amounts of data with high selectivity and sensitivity. Optimal use of the sophisticated instrumentation can be attained if the analytical chemists are guided to perform the proper experiments and to extract the useful information from the acquired data. In this thesis, strategies and methods concerning these two issues are presented.

    LC-MS method development will benefit from fundamental understanding of the processes involved. An experimental procedure was designed to determine the coefficients in a model for the electrospray process. By relating these coefficients to the experimental conditions, the influence on signal level and sensitivity for presence of matrix compounds was studied.

    For the optimization of LC-MS methods, strategies based on empirical modelling were worked out. Comparisons were made between artificial neural network (ANN) modelling and linear modelling tools, and a genetic algorithm was implemented to explore the ANN models.

    Visual interpretation and multivariate analysis of LC-MS data is hampered by background signals and noise, and a digital filter for background suppression and signal-to-noise improvement was developed. It is also important to indicate the presence of overlapping peaks, and a strategy for the assessment of peak purity was therefore worked out. These methods and several established methods were implemented in an add-on program (LC-MS Toolbox 1.0) for information extraction of LC-MS data.

    Ultimately, the data produced with LC-MS can be separated into the mass spectra, the elution profiles and the concentrations of the analytes, e.g. with PARAFAC modelling. The trilinear data structure assumed may, however, be distorted by variations in the LC conditions causing retention time shifts. An improved algorithm for time warping that can compensate for some of these deviations was worked out, and its performance as a pre-processing tool for PARAFAC was examined.

  • 167. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Intramolecular Palladium-Catalyzed 1,4-Addition to Conjugated Dienes. Stereoselective Synthesis of Fused Tetrahydrofurans and Tetrahydropyrans1992In: J. Am. Chem. Soc, Vol. 114, no 16, p. 6374-6381Article in journal (Refereed)
  • 168. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Palaldium-Catalyzed Stereocontrolled Intramolecular 1,4-Additions to Cyclic 1,3-Dienes Involving Amides as Nucleophiles1990In: J. Am. Chem. Soc, Vol. 112, no 9, p. 3683-3685Article in journal (Refereed)
  • 169. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Stereocontrolled Oxaspirocyclization of Conjugated Dienes via Palladium Catalysis1991In: J. Org. Chem. Soc, Vol. 56, no 7, p. 2274-2276Article in journal (Refereed)
  • 170. Bäckvall, Jan-E.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Vågberg, Jan O.
    Stereocontrolled Lactonization Reactions via Palladium-Catalysis1989In: Tetrahedron Letters, Vol. 30, no 1, p. 137-140Article in journal (Refereed)
  • 171. Bäckvall, Jan-E.
    et al.
    Nilsson, Ylva
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Gatti, Roberto
    Wu, Jinchang
    Carbon-Carbon Bond Formation in Palladium(II)-Catalyzed Intramolecular 1,4-Oxidation of Conjugated Dienes1994In: Tetrahedron Letters, Vol. 35, no 31, p. 5713-5716Article in journal (Refereed)
  • 172.
    Bökman, C.Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Analytisk kemi.
    Zettersten, Camilla
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Analytisk kemi.
    Sjöberg, Per J.R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Analytisk kemi.
    Nyholm, Leif
    A Setup for the Coupling of a Thin-Layer Electrochemical Flow Cell to Electrospray Mass Spectrometry2004In: Analytical Chemistry, Vol. 76, no 7, p. 2017-2024Article in journal (Refereed)
    Abstract [en]

    A novel setup for the coupling of commercially available thin-layer cell to electrospray mass spectrometry (ESI-MS) which allows the elctrochemical reactions at the counter electrode to be straightforwardly separated from the flow into the mass spectrometer has been developed. In this way interferences from reaction products formed at the counter electrode can be minimized. This reduces the risk of changes in the mass spectra as a result of electrochemical reactions in the solution. The described setup also enables the working electrode to be positioned close to the electrospray (ESI) emitter without the need for a grounding point or a long transfer line between the electrochemical cell and the electrospray emitter. By decoupling the electrochemical reactions in the flow cell and those in the electrospray emitter, improved facilities for studies of electrochemical reactions are obtained through a better control of the potential of the working electrode. The setup has been used to study the oxidation of a drug (Olsalazine), which previously has been found to involve chemical follow-up reactions. It is also demonstrated that uncharged thiols can be detected in ESI-MS after spontaneous adsorption on a gold working electrode, followed by oxidative desorption to yield sulfinates or sulfonates. This adsorption and potential-controlled desorption has been used for the preconcentration of micromolar concentrations of 1-hexanethiol as well as for desalting of solutions containing micromolar concentrations of thiols. The results indicate that the present on-line coupling of an electrochemical cell to ESI-MS provides promising possibilities for sample preconcentration, matrix exchange (including desalting), and ionization of neutral compounds, such as thiols.

  • 173.
    Büttner, Frank
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Erdélyi, Máté
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Arvidsson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    cyclo(ß-Asp-ß3-hVal-ß3-hLys)-Solid-Phase Synthesis and Solution Structure of a Water Soluble ß-Tripeptide2004In: Helvetica Chimica Acta, Vol. 87, p. 2735-2741Article in journal (Refereed)
  • 174.
    Carlsson J, Bohl Kullberg E, Capala J, Sjöberg S, Edwards K, Gedda L.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Ligands liposomes and boron neutron capture therapy2003In: Journal of Neuro-Oncology, no 62, p. 47-59Article in journal (Other scientific)
  • 175.
    Carlsson, Jörgen
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Bohl Kullberg, Erika
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Capala, Jacek
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Sjöberg, Stefan
    Edwards, Katarina
    Department of Physical Chemistry.
    Gedda, Lars
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Ligand liposomes and boron neutron capture therapy2003In: Journal of Neuro-Oncology, Vol. 62, p. 47-Article in journal (Refereed)
  • 176.
    Casher, D.L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Tsuji, H
    Katkevics, Sano A
    Katkevics, M
    Toshimitsu, A
    Tamao, K
    Kubota, M
    Kobayashi, T
    Ottosson, C.H
    David, D
    Michl, J.
    The Disilane Chromophore: Photoelectron an dElectronic Spectra of Hexaalkyldisilanes and 1, (n+,)-Disila[n.n.n]propellanes2003In: J Phys Chem A, no 107, p. 3559-3566Article in journal (Other scientific)
  • 177.
    Chajara, Khalil
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    Ottosson, Henrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    An improved pathway to 6,6-disubstituted fulvenes2004In: Tetrahedron Letters, no 45, p. 6741-6744Article in journal (Refereed)
    Abstract [en]

    Pentafulvenes with alkyl and/or aryl substituents at the exocyclic position are formed rapidly in high yields through reaction of crystalline sodium cyclopentadienide directly with the appropriate ketones.

  • 178.
    Cheng, Aiping
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Syntheses of 11C and 76Br labeled compounds via organostannanes using the Stille cross-coupling reaction and oxidative bromination2001Licentiate thesis, monograph (Other scientific)
  • 179.
    Cosquer, Guirec Y., Wang J., Naeslund C., Adams D.M., Ji W., Zhuo J-C., Anisuzzaman A.K.M.,Sjöberg S., Barth R.F., Eriksson S., Tjarks W.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Synthesis and biological evaluation of carboranyl thymidines for BNTC2001In: 221st MEDI-151, p. 151-Article in journal (Other scientific)
    Abstract [en]

    221 st MEDI-151

  • 180.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Microscale Tools for Sample Preparation, Separation and Detection of Neuropeptides2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The analysis of low abundant biological molecules is often challenging due to their chemical properties, low concentration and limited sample volumes. Neuropeptides are one group of molecules that fits these criteria. Neuropeptides also play an important role in biological functions, which makes them extra interesting to analyze. A classic chemical analysis involves sampling, sample preparation, separation and detection. In this thesis, an enhanced solid supported microdialysis method was developed and used as a combined sampling- and preparation technique. In general, significantly increased extraction efficiency was obtained for all studied peptides. To be able to control the small sample volumes and to minimize the loss of neuropeptides because of unwanted adsorption onto surfaces, the subsequent analysis steps were miniaturized to a micro total analysis system (µ-TAS), which allowed sample pre-treatment, injection, separation, manipulation and detection.

    In order to incorporate these analysis functions to a microchip, a novel microfabrication protocol was developed. This method facilitated three-dimensional structures to be fabricated without the need of clean room facilities.

    The sample pre-treatment step was carried out by solid phase extraction from beads packed in the microchip. Femtomole levels of neuropeptides were detected from samples possessing the same properties as microdialysates. The developed injection system made it possible to conduct injections from a liquid chromatographic separation into a capillary electrophoresis channel, which facilitated for advanced multidimensional separations. An electrochemical sample manipulation system was also developed. In the last part, different electrospray emitter tip designs made directly from the edge of the microchip substrate were developed and evaluated. The emitters were proven to be comparable with conventional, capillary based emitters in stability, durability and dynamic flow range. Although additional developments remain, the analysis steps described in this thesis open a door to an integrated, on-line µ-TAS for neuropeptides analysis in complex biological samples.

    List of papers
    1. A feasibility study of solid supported enhanced microdialysis
    Open this publication in new window or tab >>A feasibility study of solid supported enhanced microdialysis
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    2004 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 76, no 6, p. 1678-1682Article in journal (Refereed) Published
    Abstract [en]

    For the first time, a solid supported enhanced microdialysis methodology for analysis of neuropeptides is described. The microdialysis samples were, in this study, subsequently collected in fractions, dissolved from the solid particles, dried, and resolved in a formic acid buffer in order to make them suitable for capillary liquid chromatography-mass spectrometry. Different microdialysis flow profiles were evaluated where air-gapped continuous flow was considered most suitable for the solid supported microdialysis mode. Six endogenous neuropeptides were initially used to investigate the feasibility of this enhanced microdialysis methodology. The improved relative recovery obtained from the solid supported enhanced microdialysis was varying from no effect to 10 times higher as compared to ordinary microdialysis. The most efficient enrichment was obtained for luteinizing hormone releasing hormone, which was the largest but also the most hydrophilic of the peptides. In contrast, no significant difference in recovery was observed for Leu-enkephalin being the smallest and the most hydrophobic peptide tested. These results indicate an increased flux and selective uptake of hydrophilic peptides across the membrane and enrichment on the particles in solid supported microdialysis.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-93181 (URN)10.1021/ac035305l (DOI)15018567 (PubMedID)
    Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2017-12-14Bibliographically approved
    2. Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
    Open this publication in new window or tab >>Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
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    2005 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 16, p. 5356-5363Article in journal (Refereed) Published
    Abstract [en]

    A microchip in poly(dimethylsiloxane) (PDMS) for in-line solid-phase extraction-capillary electrophoresis-electrospray ionization-time-of-flight mass spectrometry (SPE-CE-ESI-TOF-MS) has been developed and evaluated. The chip was fabricated in a novel one-step procedure where mixed PDMS was cast over steel wires in a mold. The removed wires defined 50-um cylindrical channels. Fused-silica capillaries were inserted into the structure in a tight fit connection. The inner walls of the inserted fused-silica capillaries and the PDMS microchip channels were modified with a positively charged polymer, PolyE-323. The chip was fabricated in a two-level cross design. The channel at the lower level was packed with 5-um hyper-cross-linked polystyrene beads acting as a SPE medium used for desalting. The upper level channel acted as a CE channel and ended in an integrated emitter tip coated with conducting graphite powder to facilitate the electrical contact for sheathless ESI. An overpressure continuously provided fresh CE electrolyte independently of the flows in the different levels. Further studies were carried out in order to investigate the electrophoretic and flow rate properties of the chip. Finally, six-peptide mixtures, in different concentrations, dissolved in physiological salt solution was injected, desalted, separated, and sprayed into the mass spectrometer for analysis with a limit of detection in femtomole levels.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-74074 (URN)10.1021/ac050495g (DOI)16097780 (PubMedID)
    Available from: 2005-08-26 Created: 2005-08-26 Last updated: 2017-12-14Bibliographically approved
    3. A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
    Open this publication in new window or tab >>A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
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    2006 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 131, no 7, p. 791-798Article in journal (Refereed) Published
    Abstract [en]

    Information on protein expression, disease biomarkers or surrogate markers and genetic disorders can nowadays be achieved from analysis of complex biological samples by liquid separation coupled to mass spectrometric (MS) detection. This paper describes fast multidimensional separation by on-line liquid chromatography (LC) and capillary electrophoresis (CE), followed by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) MS detection. This detector provides ultrahigh resolution of the detected ions, mass accuracy at the ppm-level and high sensitivity. Most of the challenge of this system lies in the development of a new interface for the on-line coupling of LC to CE. The interface developed in poly(dimethylsiloxane) provides a RSD for injection repeatability of <3.5% and surface control for unspecific binding by deactivation with a cationic polymer, PolyE-323. We have evaluated the interface, as well as the overall system, with respect to robustness and deconvolution ability. Sequence coverage for bovine serum albumin (BSA) of 93% showed a high recovery of sample in the different transfer steps through the system. The detection limit for identification is 277 ng mL−1 (or 280 nM) on average for peptides. In the future, we expect LC-CE-MS to be a novel strategy for elucidating the chemistry of biological matrices.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-80932 (URN)10.1039/b601660j (DOI)
    Available from: 2006-06-29 Created: 2006-06-29 Last updated: 2017-12-14Bibliographically approved
    4. On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip to electrospray mass spectrometry
    Open this publication in new window or tab >>On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip to electrospray mass spectrometry
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    In: Article in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-93184 (URN)
    Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2011-03-21
    5. Sheathless electrospray from polymer microchips
    Open this publication in new window or tab >>Sheathless electrospray from polymer microchips
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    2003 In: Analytical Chemistry, Vol. 75, no 15, p. 3934-3940Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93185 (URN)
    Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2011-03-21
    6. Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip
    Open this publication in new window or tab >>Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip
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    2005 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 130, no 2, p. 193-199Article in journal (Refereed) Published
    Abstract [en]

    Hybrid capillary-poly(dimethysiloxane) (PDMS) microchips with integrated electrospray ionization (ESI) tips were directly fabricated by casting PDMS in a mould. The shapes of the emitter tips were drilled into the mould, which produced highly reproducible three-dimensional tips. Due to the fabrication method of the microfluidic devices, no sealing was necessary and it was possible to produce a perfect channel modified by PolyE-323, an aliphatic polyamine coating agent. A variety of different coating procedures were also evaluated for the outside of the emitter tip. Dusting graphite on a thin unpolymerised PDMS layer followed by polymerisation was proven to be the most suitable procedure. The emitter tips showed excellent electrochemical properties and durabilities. The coating of the emitter was eventually passivated, but not lost, and could be regenerated by electrochemical means. The excellent electrochemical stability was further confirmed in long term electrospray experiments, in which the emitter sprayed continuously for more than 180 h. The PolyE-323 was found suitable for systems that integrate rigid fused silica and soft PDMS technology, since it simply could be applied successfully to both materials. The spray stability was confirmed from the recording of a total ion chromatogram in which the electrospray current exhibited a relative standard deviation of 3.9% for a 30 min run. CE-ESI-MS separations of peptides were carried out within 2 min using the hybrid PDMS chip resulting in similar efficiencies as for fused silica capillaries of the same length and thus with no measurable band broadening effects, originating from the PDMS emitter.

    National Category
    Analytical Chemistry Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-93084 (URN)10.1039/b414592e (DOI)15665973 (PubMedID)
    Available from: 2005-05-03 Created: 2005-05-03 Last updated: 2017-12-14Bibliographically approved
    7. Sample pretreatment on a microchip with an integrated electrospray emitter
    Open this publication in new window or tab >>Sample pretreatment on a microchip with an integrated electrospray emitter
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    2006 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 27, no 11, p. 2075-2082Article in journal (Refereed) Published
    Keywords
    Electrospray emitter, Microchip, PDMS, Sample pretreatment
    National Category
    Chemical Sciences Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-95129 (URN)10.1002/elps.200500763 (DOI)
    Available from: 2006-11-17 Created: 2006-11-17 Last updated: 2017-12-14Bibliographically approved
  • 181.
    Danielsson, R.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Bylund, D.
    Markides, K.E.
    Matched filtering with background suppression for improved quality of base peak chromatograms and mass spectra in liquid chromatography - mass spectrometry2002In: Analytica Chimica Acta, no 454, p. 167-184Article in journal (Refereed)
  • 182. Dobrovolsky, Vasily N.
    et al.
    Bowyer, John F.
    Pabarcus, Michael K.
    Heflich, Robert H.
    Williams, Lee D.
    Doerge, Daniel R.
    Arvidsson, Björn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Casida, John E.
    Effect of arylformamidase (kynurenine formamidase) gene inactivation in mice on enzymatic activity, kynurenine pathway metabolites and phenotype2005In: Biochimica et Biophysica Acta, no 1724, p. 163-172Article in journal (Refereed)
    Abstract [en]

    The gene coding for arylformamidase (Afmid, also known as kynurenine formamidase) was inactivated in mice through the removal of a shared bidirectional promoter region regulating expression of the Afmid and thymidine kinase (Tk) genes. Afmid/Tk-deficient mice are known to develop sclerosis of glomeruli and to have an abnormal immune system. Afmid-catalyzed hydrolysis of N-formyl-kynurenine is a key step in tryptophan metabolism and biosynthesis of kynurenine-derived products including kynurenic acid, quinolinic acid, nicotinamide, NAD, and NADP. A disruption of these pathways is implicated in neurotoxicity and immunotoxicity. In wild-type (WT) mice, Afmid-specific activity (as measured by formyl-kynurenine hydrolysis) was 2-fold higher in the liver than in the kidney. Formyl-kynurenine hydrolysis was reduced by ~50% in mice heterozygous (HZ) for Afmid/Tk and almost completely eliminated in Afmid/Tk knockout (KO) mice. However, there was 13% residual formyl-kynurenine hydrolysis in the kidney of KO mice, suggesting the existence of a formamidase other than Afmid. Liver and kidney levels of nicotinamide plus NAD/NADP remained the same in WT, HZ and KO mice. Plasma concentrations of formyl-kynurenine, kynurenine, and kynurenic acid were elevated in KO mice (but not HZ mice) relative to WT mice, further suggesting that there must be enzymes other than Afmid (possibly in the kidney) capable of metabolizing formyl-kynurenine into kynurenine. Gradual kidney deterioration and subsequent failure in KO mice is consisten with high levels of tissue-specific Afmid expression in the kidney of WT but not KO mice. On this basis, the most significant function of the kynurenine pathway and Afmid in mice may be in eliminating toxic metabolites and to a lesser extent in providing intermediates for other processes.

  • 183. Dybala-Defratyka, Agnieszka
    et al.
    Rostkowski, Michal
    Matsson, Olle
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    Westaway, Kenneth C.
    Paneth, Piotr
    A New Interpretation of Chlorine Leaving Group Kinetic Isotope Effects; A Theoretical Approach2004In: J. Org. Chem., Vol. 69, p. 4900-4905Article in journal (Refereed)
    Abstract [en]

    The chlorine leaving group kinetic isotope effects (KIEs) for the SN2 reactions between methyl chloride and a wide range of anionic, neutral, and radical anion nucleophiles were calculated in the gas phase and, in several cases, using a continuum solvent model. In contrast to the expected linear dependence of the chlorine KIEs on the Ca-CI bond order in the transition state, the KIEs fell in a very small range (1.0056-1.0091), even though the Ca-CI transition state bond orders varied widely from approximately 0.32 to 0.78, a range from reactant-like to very product-like. This renders chlorine KIEs, and possibly other leaving-group KIEs, less useful for studies of reaction mechanisms than commonly assumed. A partial explanation for this unexpected relationship between the Ca-CI transition state bond order and the magnitude of the chlorine KIE is presented.

  • 184.
    Edgren, E.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Enblad, P.
    Grenvik, Å.
    Lilja, A.
    Valind, S.
    Wiklund, L.
    Hedstrand, U.
    Stjernström, H.
    Persson, L., Pontén, U.
    Långström, B.
    Cerebral blood flow and metabolism after cardiopulmonary resucitation. A pathophysiologic and prognostic positron emission tomography pilot study.2003In: Resuscitation, Vol. 57, no 228, p. 161-170Article in journal (Refereed)
  • 185.
    Edström, K
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Herranen, M
    Thermal stability of the HOPG/liquid electrolyte interphase studied by in situ electrochemical atomic force microscopy2000In: JOURNAL OF THE ELECTROCHEMICAL SOCIETY, ISSN 0013-4651, Vol. 147, no 10, p. 3628-3632Article in journal (Refereed)
    Abstract [en]

    In situ atomic force microscopy (AFM) was used to follow temperature-dependent morphological changes at a highly oriented pyrolytic graphite (HOPG)/electrolyte interface. Cyclic voltammetry was performed on an HOPG crystal covered with an electrolyte [1 M

  • 186.
    Eilers, Gerriet
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Molecular Approaches to Photochemical Solar Energy Conversion: Towards Synthetic Catalysts for Water Oxidation and Proton Reduction2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A molecular system capable of photoinduced water splitting is an attractive approach to solar energy conversion. This thesis deals with the functional characterization of molecular building blocks for the three principal functions of such a molecular system: Photoinduced accumulative charge separation, catalytic water oxidation, and catalytic proton reduction.

    Systems combining a ruthenium-trisbipyridine photosensitizer with multi-electron donors in form of dinuclear ruthenium or manganese complexes were investigated in view of the rate constants of electron transfer and excited state quenching. The kinetics were studied in the different oxidation states of the donor unit by combination of electrochemistry and time resolved spectroscopy. The rapid excited state quenching by the multi-electron donors points to the importance of redox intermediates for efficient accumulative photooxidation of the terminal donor.

    The redox behavior of manganese complexes as mimics of the water oxidizing catalyst in the natural photosynthetic reaction center was studied by electrochemical and spectroscopic methods. For a dinuclear manganese complex ligand exchange reactions were studied in view of their importance for the accumulative oxidation of the complex and its reactivity towards water. With the binding of substrate water, multiple oxidation in a narrow potential range and concomitant deprotonation of the bound water it was demonstrated that the manganese complex is capable of mimicking multiple aspects of photosynthetic water oxidation.

    A dinuclear iron complex was investigated as biomimetic proton reduction catalyst. The complex structurally mimics the active site of the iron-only hydrogenase enzyme and was designed to hold a proton on the bridging ligand and a hydride on the iron centers. Thermodynamics and kinetics of the protonation reactions and the electrochemical behavior of the different protonation states were studied in view of their potential catalytic performance.

    List of papers
    1. Iron hydrogenase active site mimic holding a proton and a hydride
    Open this publication in new window or tab >>Iron hydrogenase active site mimic holding a proton and a hydride
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    2006 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 5, p. 520-522Article in journal (Refereed) Published
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-95871 (URN)
    Available from: 2007-05-04 Created: 2007-05-04 Last updated: 2017-12-14
    2. Ligand versus metal protonation of an iron hydrogenase active site mimic
    Open this publication in new window or tab >>Ligand versus metal protonation of an iron hydrogenase active site mimic
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    2007 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 13, no 25, p. 7075-7084Article in journal (Refereed) Published
    Abstract [en]

    The protonation behavior of the iron hydrogenase active-site mimic [Fe2(u-adt)(CO)4(PMe3)2] (1; adt=N-benzyl-azadithiolate) has been investigated by spectroscopic, electrochemical, and computational methods. The combination of an adt bridge and electron-donating phosphine ligands allows protonation of either the adt nitrogen to give [Fe2(μ-Hadt)(CO)4(PMe3)2]+ ([1H]+), the Fe-Fe bond to give [Fe2-(μ-adt)(μ-H)(CO)4(PMe3)2]+ ([1Hy]+), or both sites simultaneously to give [Fe2(μ-Hadt)(μ-H)(CO)4(PMe3)2]2+ ([1HHy]2+). Complex 1 and its protonation products have been characterized in acetonitrile solution by IR, 1H, and 31PNMR spectroscopy. The solution structures of all protonation states feature a basal/basal orientation of the phosphine ligands, which contrasts with the basal/apical structure of 1 in the solid state. Density functional calculations have been performed on all protonation states and a comparison between calculated and experimental spectra confirms the structural assignments. The ligand protonated complex [1H]+ (pKa =12) is the initial, metastable protonation product while the hydride [1Hy]+ (pKa=15) is the thermodynamically stable singly protonated form. Tautomerization of cation [1H]+ to [1Hy]+ does not occur spontaneously. However, it can be catalyzed by HCl (k=2.2M-1s-1), which results in the selective formation of cation [1Hy]+. The protonations of the two basic sites have strong mutual effects on their basicities such that the hydride (pKa=8) and the ammonium proton (pKa=5) of the doubly protonated cationic complex [1HHy]2+ are considerably more acidic than in the singly protonated analogues. The formation of dication [1HHy]2+ from cation [1H]+ is exceptionally slow with perchloric or trifluoromethanesulfonic acid (k= 0.15 M-1s-1), while the dication is formed substantially faster (k > 102 M-1 s-1) with hydrobromic acid. Electrochemically, 1 undergoes irreversible reduction at -2.2V versus ferrocene, and this potential shifts to -1.6, - 1.1, and -1.0 V for the cationic complexes [1H]+, [1Hy]+, and [1HHy]2+, respectively, upon protonation. The doubly protonated form [1HHy]2+ is reduced at less negative potential than all previously reported hydrogenase models, although catalytic proton reduction at this potential is characterized by slow turnover.

    Keywords
    density functional calculations, electrochemistry, enzyme models, hydride ligands, tautomerism
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-95872 (URN)10.1002/chem.200700019 (DOI)000249294300005 ()17566128 (PubMedID)
    Available from: 2007-05-04 Created: 2007-05-04 Last updated: 2017-12-14Bibliographically approved
    3. Synthesis and characterization of dinuclear ruthenium complexes covalently linked to Ru(II) tris-bipyridine: an approach to mimics of the donor side of photosystem II
    Open this publication in new window or tab >>Synthesis and characterization of dinuclear ruthenium complexes covalently linked to Ru(II) tris-bipyridine: an approach to mimics of the donor side of photosystem II
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    2005 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 11, no 24, p. 7305-7314Article in journal (Refereed) Published
    Abstract [en]

    The structural rearrangements triggered by oxidation of the dinuclear Mn complex [Mn2(bpmp)(u-OAc)2]+ (bpmp = 2,6-bis[bis(2-pyridylmethyl)amino]methyl-4-methylphenol anion) in the presence of water have been studied by combinations of electrochemistry with IR spectroscopy and with electrospray ionization mass spectrometry (ESI-MS). The exchange of acetate bridges for water (D2O) derived ligands in different oxidation states could be monitored by mid-IR spectroscopy in CD3CN-D2O mixtures following the Vas(C-O) bands of bound acetate at 1594.4 cm-1 (II,II), 1592.0 cm-1 (II,III) and 1586.5 cm-1 (III,III). Substantial loss of bound acetate occurs at much lower water content (<0.5% v/v) in the III,III state than in the II,II and II,III states (>10%). The ligand-exchange reactions do not initially reduce the overall charge of the complex but facilitate further oxidation by proton-coupled electron transfer as the water-derived ligands are increasingly deprotonated in higher oxidation states. In the IR spectra deprotonation could be followed by the formation of acetic acid (DOAc, ~1725 cm-1, V(C-O)) from the released acetate (1573.6 cm-1, Vas(C-O)). By the on-line combination of an electrochemical flow cell with ESI-MS several product complexes could be identified. A di-u-oxo bridged III,IV dimer [Mn2(bpmp)(u-O)2]2+ (m/z 335.8) can be generated at potentials below the III,III/II,III couple of the di-u-acetato complex (0.61 V Vs. ferrocene). The ligand-exchange reactions allow for three metal-centered oxidation steps to occur from II,II to III,IV in a potential range of only 0.5 V, explaining the formation of a spin-coupled III,IV dimer by photo-oxidation with [Ru(bpy)3]3+ in previous EPR studies.

    Keywords
    electrochemistry, electron transfer, mixed-valent compounds, ruthenium cluster, sensitizers
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-95873 (URN)10.1002/chem.200500592 (DOI)16163754 (PubMedID)
    Available from: 2007-05-04 Created: 2007-05-04 Last updated: 2017-12-14
    4. Ligand exchange upon oxidation of a dinuclear Mn complex - Detection of structural changes by FT-IR spectroscopy and ESI-MS.
    Open this publication in new window or tab >>Ligand exchange upon oxidation of a dinuclear Mn complex - Detection of structural changes by FT-IR spectroscopy and ESI-MS.
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    2005 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, no 6, p. 1033-1041Article in journal (Refereed) Published
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-95874 (URN)
    Available from: 2007-05-04 Created: 2007-05-04 Last updated: 2017-12-14
    5. Synthesis and redox properties of a [meso-tris(4-nitrophenyl) corrolato]Mn(III) complex.
    Open this publication in new window or tab >>Synthesis and redox properties of a [meso-tris(4-nitrophenyl) corrolato]Mn(III) complex.
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    2005 (English)In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, no 9(6), p. 379-386Article in journal (Refereed) Published
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-95875 (URN)
    Available from: 2007-05-04 Created: 2007-05-04 Last updated: 2017-12-14
  • 187.
    Eilers, Gerriet
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Zettersten, Camilla
    Nyholm, Leif
    Hammarström, Leif
    Lomoth, Reiner
    Ligand exchange upon oxidation of a dinuclear Mn complex - Detection of structural changes by FT-IR spectroscopy and ESI-MS.2005In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, no 6, p. 1033-1041Article in journal (Refereed)
  • 188. Ekegren, J. K.
    et al.
    Modin, S. A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Alonso, D. A.
    Andersson, P. G.
    Multigram scale synthesis of auselful aza-Diels-Alder adduct in a one-step procedure2002In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 13, no 4, p. 447-449Article in journal (Refereed)
  • 189.
    Ekegren, Jenny
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Synthesis of New Chiral N, S- and N, O-Ligands. Evaluation in Asymetric Transfer Hydrogenation2002Licentiate thesis, monograph (Other scientific)
  • 190.
    Ekegren, Jenny
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Modin, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Alonso, Diego
    Andersson, Pher
    Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Multigram scale synthesis of a useful aza-Diels-Alder adduct in a one-step procedure2002In: Tetrahedron Asymmetry, no 13, p. 447-449Article in journal (Refereed)
  • 191. Ekegren, Jenny
    et al.
    Roth, Peter
    Källström, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Tarnai, Tibor
    Andersson, Pher
    Synthesis and evaluation of N,S-compounds as chiral ligands for transfer hydrogenation of acetophenone.2003In: Organic & Biomolecular Chemistry, ISSN 1477-0520, Vol. 1, no 2, p. 358-366Article in journal (Refereed)
  • 192.
    Ekegren, Jenny
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Roth, Peter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Källström, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Tarnai, Tibor
    Andersson, Pher
    Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Synthesis and evaluation of N,S-compounds as chiral ligands for transfer hydrogenation of acetophenone2003In: Org. Biomol. Chem, no 1, p. 358-366Article in journal (Refereed)
  • 193.
    Ekegren J.K, Roth P, Källström K, Tarnai T, Andersson P.G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
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