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  • Cobalt-Catalysed Alkene Hydrogenation: A Metallacycle Can Explain the Hydroxyl Activating Effect and the Diastereoselectivity 

    Morello, Glenn Robert; Zhong, Hongyu; Chirik, Paul J.; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-04)
    Bis(phosphine)cobalt dialkyl complexes have been reported to be highly active in the hydrogenation of tri-substituted alkenes bearing hydroxyl substituents. Alkene substrates containing ether, ester, or ketone substituents show minimal reactivity, indicating an activating effect of the hydroxyl group. The mechanistic details of bis(phosphine)cobalt-catalysed hydrogenation were recently evaluated ...
  • Stepwise Deoxygenation of Nitrite as a Route to Two Families of Ruthenium Corroles: Group 8 Periodic Trends and Relativistic Effects 

    Alemayehu, Abraham; Vazquez Lima, Hugo; Gagnon, Kevin J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-19)
    Given the many applications of ruthenium porphyrins, the rarity of ruthenium corroles and the underdeveloped state of their chemistry are clearly indicative of an area ripe for significant breakthroughs. The tendency of ruthenium corroles to form unreactive metal–metal-bonded dimers has been recognized as a key impediment in this area. Herein, by exposing free-base meso-tris(p-X-phenyl)corroles, ...
  • Exploring the role of L209 residue in the active site of NDM-1 a metallo-β-lactamase 

    Marcoccia, Francesca; Leiros, Hanna-Kirsti S.; Aschi, Massimiliano; Amicosante, Gianfranco; Perilli, Mariagrazia (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-02)
    Background:<br> New Delhi Metallo-β-Lactamase (NDM-1) is one of the most recent additions to the β-lactamases family. Since its discovery in 2009, NDM-1 producing Enterobacteriaceae have disseminated globally. With few effective antibiotics against NDM-1 producers, there is an urgent need to design new drug inhibitors through the help of structural and mechanistic information available from ...
  • Comparative conformational analyses and molecular dynamics studies of glycylglycine methyl ester and glycylglycine N -methylamide 

    Thakkar, Balmukund S.; Engh, Richard Alan (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-24)
    Compared to their amide analogs, peptidic esters have a lower propensity for intramolecular hydrogen bonding, and thus most likely quite different stable geometries. On the other hand, their similarity and facile conversion to peptides has led to their broad use in synthetic and biological applications. This dichotomy creates a need to understand their conformational properties. Here, we study the ...
  • Density Functional Studies on Secondary Amides: Role of Steric Factors in Cis/Trans Isomerization 

    Thakkar, Balmukund; Svendsen, John Sigurd Mjøen; Engh, Richard Alan (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-25)
    Cis/trans isomerization of amide bonds is a key step in a wide range of biological and synthetic processes. Occurring through C-N amide bond rotation, it also coincides with the activation of amides in enzymatic hydrolysis. In recently described QM studies of cis/trans isomerization in secondary amides using density functional methods, we highlighted that a peptidic prototype, such as glycylglycine ...
  • Modeled deposition of nitrogen and sulfur in Europe estimated by 14 air quality model systems: evaluation, effects of changes in emissions and implications for habitat protection 

    Vivanco, Marta García; Theobald, Mark R.; García-Gómez, Héctor; Garrido, Juan Luis; Prank, Marje; Aas, Wenche; Adani, Mario; Aluyz, Ummugulsum; Andersson, Camilla; Bellasio, Roberto; Bessagnet, Bertrand; Bianconi, Fabio; Bieser, Johannes; Brandt, Jørgen; Briganti, Gino; Cappelletti, Andrea; Curci, Gabriele; Christensen, Jesper H.; Colette, Augustin; Couvidat, Florian; Cuvelier, Cornelis; D'Isidoro, Massimo; Flemming, Johannes; Fraser, Andrea; Geels, Camilla; Hansen, Kaj M.; Hogrefe, Christian; Im, Ulas; Jorba, Oriol; Kitwiroon, Nutthida; Manders, Astrid; Mircea, Mihaela; Otero, Noelia; Pay, Maria-Teresa; Pozzoli, Luca; Solazzo, Efisio; Tsyro, Svetlana; Unal, Alper; Wind, Peter; Galmarini, Stefano (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-17)
    <p>The evaluation and intercomparison of air quality models is key to reducing model errors and uncertainty. The projects AQMEII3 and EURODELTA-Trends, in the framework of the Task Force on Hemispheric Transport of Air Pollutants and the Task Force on Measurements and Modelling, respectively (both task forces under the UNECE Convention on the Long Range Transport of Air Pollution, LTRAP), have brought ...
  • Enantioselective incorporation of CO2: status and potential 

    Vaitla, Janakiram; Guttormsen, Yngve; Mannisto, Jere K.; Nova, Ainara; Repo, Timo; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-09)
    CO<sub>2</sub> is a promising and sustainable carbon feedstock for organic synthesis. New catalytic protocols for efficient incorporation of CO<sub>2</sub>into organic molecules are continuously being reported. However, little progress has been made in the enantioselective conversion of CO<sub>2</sub>to form enantioenriched molecules. In order to allow CO<sub>2</sub>to become a versatile carbon ...
  • Geometric Energy Derivatives at the Complete Basis Set Limit: Application to the Equilibrium Structure and Molecular Force Field of Formaldehyde 

    Morgan, W. James; Matthews, Devin A; Ringholm, Magnus; Agarwal, Jay; Gong, Justin Z; Ruud, Kenneth; Allen, Wesley D.; Stanton, John F.; Schaefer, Henry F. III (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-23)
    Geometric energy derivatives which rely on core-corrected focal-point energies extrapolated to the complete basis set (CBS) limit of coupled cluster theory with iterative and noniterative quadruple excitations, CCSDTQ and CCSDT(Q), are used as elements of molecular gradients and, in the case of CCSDT(Q), expansion coefficients of an anharmonic force field. These gradients are used to determine the ...
  • A multi-model comparison of meteorological drivers of surface ozone over Europe 

    Otero, Noelia; Sillmann, Jana; Mar, Kathleen; Rust, Henning W.; Solberg, Sverre; Andersson, Camilla; Engardt, Magnuz; Bergström, Robert; Bessagnet, Bertrand; Colette, Augustin; Couvidat, Florian; Cuvelier, Cornelius; Tsyro, Svetlana; Fagerli, Hilde; Schaap, Martijn; Manders, Astrid; Mircea, Mihaela; Briganti, Gino; Cappelletti, Andrea; Adani, Mario; D'Isidoro, Massimo; Pay, María Teresa; Theobald, Mark; Vivanco, Marta G.; Wind, Peter Ariaan; Ojha, Narendra; Raffort, Valentin; Butler, Tim (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-24)
    The implementation of European emission abatement strategies has led to a significant reduction in the emissions of ozone precursors during the last decade. Ground-level ozone is also influenced by meteorological factors such as temperature, which exhibit interannual variability and are expected to change in the future. The impacts of climate change on air quality are usually investigated through ...
  • Benchmarking the Performance of Exchange-Correlation Functionals for Predicting Two-Photon Absorption Strengths 

    Beerepoot, Maarten; Alam, MD Mehboob; Bednarska, Joanna; Bartkowiak, Wojciech; Ruud, Kenneth; Zaleśny, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-31)
    The present work investigates the performance of exchange–correlation functionals in the prediction of two-photon absorption (2PA) strengths. For this purpose, we considered six common functionals used for studying 2PA processes and tested these on six organoboron chelates. The set consisted of two semilocal (PBE and BLYP), two hybrid (B3LYP and PBE0), and two range-separated (LC-BLYP and CAM-B3LYP) ...
  • Darmstadtium, roentgenium, and copernicium form strong bonds with cyanide 

    Demissie, Taye Beyene; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-05)
    We report the structures and properties of the cyanide complexes of three superheavy elements (darmstadtium, roentgenium, and copernicium) studied using two‐ and four‐component relativistic methodologies. The electronic and structural properties of these complexes are compared to the corresponding complexes of platinum, gold, and mercury. The results indicate that these superheavy elements form ...
  • The influence of sediment properties and experimental variables on the efficiency of electrodialytic removal of metals from sediment 

    Pedersen, Kristine Bondo; Lejon, Tore; Jensen, Pernille E.; Ottosen, Lisbeth M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-16)
    <p>Chemometrics was used to determine the influence of sediment properties and experimental settings for the electrodialytic removal (EDR) of Cu, Pb and Zn from six harbour sediments from Greenland and Norway. A Projection onto latent structures (PLS) model revealed that the most important sediment properties for achieving acidification (lag-phase, pH > 4), necessary for desorbing and mobilising ...
  • The MAR databases: development and implementation of databases specific for marine metagenomics 

    Klemetsen, Terje; Raknes, Inge A.; Fu, Juan; Agafonov, Alexander; Balasundaram, Sudhagar V.; Tartari, Giacomo; Robertsen, Espen; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-02)
    We introduce the marine databases; <i>MarRef, MarDB</i> and <i>MarCat</i> (https://mmp.sfb.uit.no/databases/), which are publicly available resources that promote marine research and innovation. These data resources, which have been implemented in the Marine Metagenomics Portal (MMP) (https://mmp.sfb.uit.no/), are collections of richly annotated and manually curated contextual (metadata) and sequence ...
  • Caffeine supplementation does not affect match activities and fatigue resistance during match play in young football players 

    Pettersen, Svein Arne; Krustrup, Peter; Bendiksen, Mads; Randers, Morten B.; Brito, Joao; Bangsbo, Jens; Yun, Jin; Mohr, Magni (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-30)
    The study examined the effect of caffeine supplementation on match activities and development of fatigue during a football match. In a randomised, double-blind cross-over design, two experimental football games separated by 7 days were organised between the junior teams of two professional football clubs (17.6 ± 1.1 years (±s), 71.7 ± 6.9 kg, 13.9% ± 5.0% body fat). The players ingested either a ...
  • An Acylation-Finkelstein Approach to Radioiodination of Bioactives: The Role of Amide Group Anchimeric Assistance 

    Fjellaksel, Richard; Dugalic, Damir; Demissie, Taye Beyene; Riss, Patrick; Hjelstuen, Ole Kristian; Sundset, Rune; Hansen, Jørn H (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-28)
    Herein, we report a straightforward sequential acylation‐Finkelstein approach to achieve iodination of amine containing bioactives. The utility was demonstrated by successful radiolabelling with <sup>123</sup>I in high radiochemical yield. Moreover, microwave‐assisted Finkelstein reaction can be employed to enhance conversion and reaction rates to obtain the desired iodides. The method is of interest ...
  • Electron and nuclear spin polarization in Rb-Xe spin-exchange optical hyperpolarization 

    Hanni, Matti; Lantto, Perttu; Repiský, Michal; Mareš, Jiří; Saam, Brian; Vaara, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03)
    Spin-exchange optical hyperpolarization of <sup>129</sup>Xe gas enhances the signal-to-noise ratio in nuclear magnetic resonance experiments. The governing parameter of the Rb-Xe spin-exchange process, the so-called enhancement factor, was recently reevaluated experimentally. However, the underlying hyperfine coupling and atomic interaction potential as functions of the internuclear distance of the ...
  • Carbon-carbon bonds with CO2: Insights from computational studies 

    Obst, Marc Ferry; Pavlovic, Ljiljana; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-17)
    In this mini-review, we provide an overview of recent computational studies on homogeneous transition metal-catalyzed carbon-carbon bond formation with CO2. We cover substitution and addition reactions involving different metals (mainly Ni, Rh, Cu) and substrates (alkanes, alkenes, alkynes, arenes) with focus on the mechanistic details. The CO2 insertion step is generally found to be rate-limiting. ...
  • Prevention of Marine Biofouling Using the Natural Allelopathic Compound Batatasin-III and Synthetic Analogues 

    Moodie, Lindon; Trepos, Rozenn; Cervin, Gunnar; Bråthen, Kari Anne; Lindgård, Bente; Reiersen, Rigmor; Cahill, Patrick; Pavia, Henrik; Hellio, Claire; Svenson, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-21)
    The current study reports the first comprehensive evaluation of a class of allelopathic terrestrial natural products as antifoulants in a marine setting. To investigate the antifouling potential of the natural dihydrostilbene scaffold, a library of 22 synthetic dihydrostilbenes with varying substitution patterns, many of which occur naturally in terrestrial plants, were prepared and assessed for ...
  • Interplay of twist angle and solvents with two-photon optical channel interference in aryl-substituted BODIPY dyes 

    Alam, MD Mehboob; Misra, Ramprasad; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-11)
    Channel interference plays a crucial role in understanding the physics behind multiphoton absorption processes. In this work, we study the role of channel interference and solvent effects on the two-photon absorption in aryl-substituted boron dipyrromethene (BODIPY) dyes, a class of intramolecular charge-transfer (ICT) molecules. For this purpose, we consider fourteen dyes of this class with various ...
  • The Elephant in the Room of Density Functional Theory Calculations 

    Jensen, Stig Rune; Saha, Santanu; Flores-Livas, Jose A; Huhn, William; Blum, Volker; Goedecker, Stefan; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-14)
    Using multiwavelets, we have obtained total energies and corresponding atomization energies for the GGA-PBE and hybrid-PBE0 density functionals for a test set of 211 molecules with an unprecedented and guaranteed μHartree accuracy. These quasi-exact references allow us to quantify the accuracy of standard all-electron basis sets that are believed to be highly accurate for molecules, such as Gaussian-type ...

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