Viser treff 294-313 av 527

    • Mechanistic Insights into Carbamate Formation from CO2 and Amines: The Role of Guanidine–CO2 Adducts, 

      Mannisto, Jere K.; Pavlovic, Ljiljana; Tiainen, Tony; Nieger, Martin; Sahari, Aleksi; Hopmann, Kathrin Helen; Repo, Timo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-02)
      Capture of CO<sub>2</sub> by amines is an attractive synthetic strategy for the formation of carbamates. Such reactions can be mediated by superbases, such as 1,1,3,3-tetramethylguanidine (TMG), with previous implications that zwitterionic superbase–CO<sub>2</sub> adducts are able to actively transfer the carboxylate group to various substrates. Here we report a detailed investigation of zwitterionic ...
    • Mechanistic Insights into Copper-Catalyzed Carboxylations 

      Obst, Marc; Gevorgyan, Ashot; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-02)
      The copper-NHC-catalyzed carboxylation of organoboranes with CO<sub>2</sub> was investigated using computational and experimental methods. The DFT and DLPNO-CCSD(T) results indicate that nonbenzylic substrates are converted via an inner-sphere carboxylation of an organocopper intermediate, whereas benzylic substrates may simultaneously proceed along both inner- and outer-sphere CO<sub>2</sub> insertion ...
    • Mechanistic Investigations of the Asymmetric Hydrogenation of Enamides with Neutral Bis(phosphine) Cobalt Precatalysts 

      Mendelsohn, Lauren N.; Pavlovic, Ljiljana; Zhong, Hongyu; Friedfeld, Max R.; Shevlin, Michael; Hopmann, Kathrin Helen; Chirik, Paul J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-11)
      The mechanism of the asymmetric hydrogenation of prochiral enamides by well-defined, neutral bis(phosphine) cobalt(0) and cobalt(II) precatalysts has been explored using(R,R)-<sup>iPr</sup>DuPhos ((R,R)-<sup>iPr</sup>DuPhos = (+)-1,2-bis[(2R,5R)-2,5-diisopropylphospholano]benzene) as a representative chiral bis(phosphine) ligand. A series of (R,R)-(<sup>iPr</sup>DuPhos)Co(enamide) (enamide = ...
    • A Mechanistic Study of the Cu-catalyzed N-arylation of Hydantoin with Aryl(TMP)iodonium Salts 

      Nova Flores, Ainara; Berntsen, Linn Neerbye (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-16)
      The use of diaryliodonium salts in organic reactions has rapidly increased in the last decade because of their efficiency in arylation reactions. Despite this, mechanistic investigations are still scarce, particularly for copper catalyzed N-arylation reactions. Recently, we published the use of the unsymmetrical aryl(TMP)iodonium salts (TMP=2,4,6-trimethoxyphenyl) for the selective Cu-catalyzed ...
    • Metallaaromaticity - a protean world 

      Cuyacot, Ben Joseph R.; Badri, Zahra; Ghosh, Abhik; Foroutan-Nejad, Cina (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-01)
      The nature of magnetically induced current densities (MICD) of metallabenzenes and related compounds has been examined with relativistic DFT calculations to assess the magnetic aromaticity of the molecules. The origin of the total MICD has been analyzed in terms of individual molecular orbital (MO) contributions. Our study reveals that the s-framework of the molecules always makes a diamagnetic ...
    • Metallo-β-Lactamase Inhibitor Phosphonamidate Monoesters 

      Palica, Katarzyna; Vorácová, Manuela; Skagseth, Susann; Andersson Rasmussen, Anna; Allander, Lisa; Hubert, Madlen; Sandegren, Linus; Leiros, Hanna-Kirsti S.; Andersson, Hanna; Erdélyi, Máté (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-25)
      Being the second leading cause of death and the leading cause of disability-adjusted life years worldwide, infectious diseases remain-contrary to earlier predictions-a major consideration for the public health of the 21st century. Resistance development of microbes to antimicrobial drugs constitutes a large part of this devastating problem. The most widely spread mechanism of bacterial resistance ...
    • Metallo-β-lactamase inhibitors by bioisosteric replacement: preparation, activity and binding 

      Skagseth, Susann; Akhter, Sundus; Paulsen, Marianne H; Muhammad, Zeeshan; Samuelsen, Ørjan; Leiros, Hanna-Kirsti S.; Bayer, Annette (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-14)
      Bacterial resistance is compromising the use of β-lactam antibiotics including carbapenems. The main resistance mechanism against β-lactams is hydrolysis of the β-lactam ring mediated by serine- or metallo-β-lactamases (MBLs). Although several inhibitors of MBLs have been reported, none has been developed into a clinically useful inhibitor. Mercaptocarboxylic acids are among the most prominent ...
    • Methanotroph populations and CH 4 oxidation potentials in High Arctic peat are altered by herbivory induced vegetation change 

      Rainer, Edda Marie; Seppey, Victor William Christophe; Tveit, Alexander Tøsdal; Svenning, Mette Marianne (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-08)
      Methane oxidizing bacteria (methanotrophs) within the genus <i>Methylobacter</i> constitute the biological filter for methane (CH<sub>4</sub>) in many Arctic soils. Multiple <i>Methylobacter</i> strains have been identified in these environments but we seldom know the ecological significance of the different strains. High-Arctic peatlands in Svalbard are heavily influenced by herbivory, leading to ...
    • Methyl 5-nitro-2-(phenylamino)pyridine-4-carboxylate 

      Hansen, Lars Kr; Tjosas, F; Tjosås, Freddy; Fiksdahl, A (Journal article; Tidsskriftartikkel; Peer reviewed, 2006)
    • The Methylococcus capsulatus (Bath) secreted protein, MopE*, binds both reduced and oxidized copper. 

      Ve, Thomas; Mathisen, Karina; Helland, Ronny; Karlsen, Odd Andre; Fjellbirkeland, Anne; Røhr, Åsmund Kjendseth; Andersson, K. Kristoffer; Pedersen, Rolf B.; Lillehaug, Johan R.; Jensen, Harald B (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Under copper limiting growth conditions the methanotrophic bacterium Methylococcus capsulatus (Bath) secrets essentially only one protein, MopE*, to the medium. MopE* is a copper-binding protein whose structure has been determined by X-ray crystallography. The structure of MopE* revealed a unique high affinity copper binding site consisting of two histidine imidazoles and one kynurenine, the latter ...
    • Microwave‐Assisted Synthesis of Heterocycles from Aryldiazoacetates 

      Kristoffersen, Tone; Elumalai, Vijayaragavan; Starck, Eliot; Cousin, Étienne; Hansen, Stephanie Ramona; Hansen, Jørn H (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-17)
      Herein, we describe a rapid microwave-assisted, metal-free synthesis of substituted quinoxalinones and quinoxalines using the carbene-mediated reaction between aryldiazo esters and 1,2-diamines. The reaction can encompass a range of substituents and structural variations to afford quinoxalin-2-ones in 14–80 % yield and corresponding quinoxalines in good to excellent yields upon oxidation (67–96 %). ...
    • MiMiC: A Novel Framework for Multiscale Modeling in Computational Chemistry 

      Olsen, Jógvan Magnus Haugaard; Bolnykh, Viacheslav; Meloni, Simone; Ippoliti, Emiliano; Bircher, Martin Peter; Carloni, Paolo; Rothlisberger, Ursula (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-18)
      We present a flexible and efficient framework for multiscale modeling in computational chemistry (MiMiC). It is based on a multiple-program multiple-data (MPMD) model with loosely coupled programs. Fast data exchange between programs is achieved through the use of MPI intercommunicators. This allows exploiting the existing parallelization strategies used by the coupled programs while maintaining a ...
    • MiMiC: Multiscale Modeling in Computational Chemistry 

      Bolnykh, Viacheslav; Olsen, Jógvan Magnus Haugaard; Meloni, Simone; Bircher, Martin P; Ippoliti, Emiliano; Carloni, Paolo; Rothlisberger, Ursula (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-20)
      Hybrid quantum mechanics/molecular mechanics (QM/MM) approaches are commonly used methods for investigating a plethora of chemical, biochemical, and biophysical processes that require explicit treatment of the electronic degrees of freedom when the system is too big to be entirely treated by QM methods alone (Warshel and Levitt, 1976; Senn and Thiel, 2009; Adhireksan et al., 2014; Campomanes et al., ...
    • miRNAs Predicted to Regulate Host Anti-viral Gene Pathways in IPNV-Challenged Atlantic Salmon Fry Are Affected by Viral Load, and Associated With the Major IPN Resistance QTL Genotypes in Late Infection 

      Woldemariam, Nardos Tesfaye; Agafonov, Oleg; Sindre, Hilde; Høyheim, Bjørn; Houston, Ross D.; Robledo, Diego; Bron, James E.; Andreassen, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-11)
      Infectious pancreatic necrosis virus (IPNV) infection has been a major problem in salmonid aquaculture. Marker-assisted selection of individuals with resistant genotype at the major IPN quantitative trait locus (IPN-QTL) has significantly reduced mortality in recent years. We have identified host miRNAs that respond to IPNV challenge in salmon fry that were either homozygous resistant (RR) or ...
    • Mobile group I introns at nuclear rDNA position L2066 harbor sense and antisense homing endonuclease genes intervened by spliceosomal introns 

      Lian, Kjersti; Furulund, Betty Martine Normann; Tveita, Anders Aune; Haugen, Peik; Johansen, Steinar Daae (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-08)
      Background: Mobile group I introns encode homing endonucleases that confer intron mobility initiated by a double-strand break in the intron-lacking allele at the site of insertion. Nuclear ribosomal DNA of some fungi and protists contain mobile group I introns harboring His-Cys homing endonuclease genes (HEGs). An intriguing question is how protein-coding genes embedded in nuclear ribosomal DNA ...
    • 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 ...
    • Molecular Characterization of Cold Adaptation of Membrane Proteins in the Vibrionaceae Core-Genome 

      Kahlke, Tim; Thorvaldsen, Steinar (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Cold-adaptation strategies have been studied in multiple psychrophilic organisms, especially for psychrophilic enzymes. Decreased enzyme activity caused by low temperatures as well as a higher viscosity of the aqueous environment require certain adaptations to the metabolic machinery of the cell. In addition to this, low temperature has deleterious effects on the lipid bilayer of bacterial membranes ...
    • A molecular phylogeny of wood-borers (Teredinidae) from Japanese Tsunami Marine Debris 

      Treneman, Nancy C.; Borges, Luisa M. S.; Shipway, Reuben; Raupach, Michael J.; Altermark, Bjørn; Carlton, James T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02)
      The family Teredinidae (shipworms) contains 70-plus species of boring bivalves specialized to live in and digest wood. Traditional means of species identification and taxonomy of this group encounter numerous challenges, often compounded by the diverse and dynamic nature of shipworm ecology and distribution. Modern integrative taxonomic methods are shedding new light on this complex group, from ...
    • Molecular quantum mechanical gradients within the polarizable embedding approach-Application to the internal vibrational Stark shift of acetophenone 

      List, Nanna Holmgaard; Beerepoot, Maarten T. P.; Olsen, Jógvan Magnus Haugaard; Gao, Bin; Ruud, Kenneth; Jensen, Hans Jørgen Aagaard; Kongsted, Jacob (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-21)
      We present an implementation of analytical quantum mechanical molecular gradients within the polarizable embedding (PE) model to allow for efficient geometry optimizations and vibrational analysis of molecules embedded in large, geometrically frozen environments. We consider a variational ansatz for the quantum region, covering (multiconfigurational) self-consistent-field and Kohn–Sham density ...
    • Molecular Structure of Copper and μ-Oxodiiron Octafluorocorrole Derivatives: Insights into Ligand Noninnocence 

      Thomas, Kolle E.; Settineri, Nicholas S.; Teat, Simon J.; Steene, Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-23)
      Single-crystal X-ray structures were obtained for the copper and μ-oxodiiron complexes of 2,3,7,8,12,13,17,18-octafluoro-5,10,15-triphenylcorrole, hereafter denoted as Cu[F8TPC] and {Fe[F8TPC]}2O. A comparison with the crystal structures of other undecasubstituted Cu corroles, including those with H, Ar, Br, I, and CF3 as β-substituents, showed that the degree of saddling increases in the order: H ...