Now showing items 401-420 of 581

    • One‐Pot Synthesis of a bis‐Pocket Corrole through a 14‐fold Bromination Reaction 

      Norheim, Hans-Kristian; Schneider, Christian; Gagnon, Kevin J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-14)
      A one-pot protocol, effecting 14-fold bromination with elemental bromine, has afforded copper beta-octabromo-meso-tris(2,6-dibromo-3,5-dimethoxyphenyl)corrole, a new bis-pocket metallocorrole. The Cu complex underwent smooth demetalation under reductive conditions, affording the free corrole ligand, which in turn could be readily complexed to Mn<sup>III</sup> and Au<sup>III</sup>.A single-crystal ...
    • The Dalton quantum chemistry program system 

      Aidas, Kestutis; Angeli, Celestino; Bak, Keld L.; Bakken, Vebjørn; Bast, Radovan; Boman, Linus; Christiansen, Ove; Cimiraglia, Renzo; Coriani, Sonja; Dahle, Pål; Dalskov, Erik K.; Ekström, Ulf Egil; Enevoldsen, Thomas; Eriksen, Janus J.; Ettenhuber, Patrick; Fernández, Berta; Ferrighi, Lara; Fliegl, Heike; Frediani, Luca; Hald, Kasper; Halkier, Asger; Hattig, Christof; Heiberg, Hanne; Helgaker, Trygve; Hennum, Alf Christian; Hettema, Hinne; Hjertenæs, Eirik; Høst, Stine; Høyvik, Ida Marie; Iozzi, Maria Francesca; Jansik, Brannislav; Jensen, Hans-Jørgen Aa.; Jonsson, Dan Johan; Jørgensen, Poul; Kauczor, Johanna; Kirpekar, Sheela; Kjærgaard, Thomas; Klopper, Wim; Knecht, Stefan; Kobayashi, Rika; Koch, Henrik; Kongsted, Jacob; Krapp, Andreas; Kristensen, Kasper; Ligabue, Andrea; Lutnæs, Ola B.; Melo, Juan I.; Mikkelsen, Kurt V.; Myhre, Rolf Heilemann; Neiss, Christian; Nielsen, Christian B.; Norman, Patrick; Olsen, Jeppe; Olsen, Jogvan Magnus H.; Osted, Anders; Packer, Martin J.; Pawlowski, Filip; Pedersen, Thomas Bondo; Provasi, Patricio F.; Reine, Simen Sommerfelt; Rinkevicius, Zilvinas; Ruden, Torgeir A.; Ruud, Kenneth; Rybkin, Vladimir V.; Salek, Pawel; Samson, Claire C. M.; Sanchez de Meras, Alfredo; Saue, Trond; Sauer, Stephan P. A.; Schimmelpfennig, Bernd; Sneskov, Kristian; Steindal, Arnfinn Hykkerud; Sylvester-Hvid, Kristian O.; Taylor, Peter R.; Teale, Andrew M.; Tellgren, Erik; Tew, David P.; Thorvaldsen, Andreas J.; Thøgersen, Lea; Vahtras, Olav; Watson, Mark A.; Wilson, David J. D.; Ziolkowski, Marcin; Ågren, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-05)
      Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree–Fock, Kohn–Sham, multiconfigurational self-consistent-field, Møller–Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients ...
    • A Dihydride Mechanism Can Explain the Intriguing Substrate Selectivity of Iron-PNP-Mediated Hydrogenation 

      Hopmann, Kathrin Helen; Morello, Glenn Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-24)
      Iron-PNP pincer complexes are efficient catalysts for the hydrogenation of aldehydes and ketones. A variety of hydrogenation mechanisms have been proposed for these systems, but there appears to be no clear consensus on a preferred pathway. We have employed high-level quantum chemical calculations to evaluate various mechanistic possibilities for iron-PNP catalysts containing either CH2, NCH3, ...
    • Averaged Solvent Embedding Potential Parameters for Multiscale Modeling of Molecular Properties 

      Beerepoot, Maarten; Steindal, Arnfinn Hykkerud; List, Nanna Holmgaard; Kongsted, Jacob; Olsen, Jógvan Magnus Haugaard (Journal article; Tidsskriftartikkel, 2016-03-03)
      We derive and validate averaged solvent parameters for embedding potentials to be used in polarizable embedding quantum mechanics/molecular mechanics (QM/MM) molecular property calculations of solutes in organic solvents. The parameters are solvent-specific atom-centered partial charges and isotropic polarizabilities averaged over a large number of geometries of solvent molecules. The use ...
    • The Blue–Violet Color of Pentamethylbismuth: A Visible Spin-Orbit Effect 

      Conradie, Jeanet; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-22)
      Two-component relativistic time-dependent density functional theory calculations with spin-orbit coupling predict yellow and orange–red absorption for BiPh5 and BiMe5, respectively, providing an excellent explanation for their respective violet and blue–violet colors. According to the calculations, the visible absorption is clearly attributable to a single transition from a ligand-based HOMO ...
    • Pan genome and CRISPR analyses of the bacterial fish pathogen Moritella viscosa 

      Karlsen, Christian; Hjerde, Erik; Klemetsen, Terje; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-20)
      Background: Winter-ulcer Moritella viscosa infections continue to be a significant burden in Atlantic salmon (Salmo salar L.) farming. M. viscosa comprises two main clusters that differ in genetic variation and phenotypes including virulence. Horizontal gene transfer through acquisition and loss of mobile genetic elements (MGEs) is a major driving force of bacterial diversification. To gain insight ...
    • The origin dependence of the material constants: the permittivity and the inverse permeability 

      Anelli, Marco; Jonsson, Dan Johan; Fliegl, Heike; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-26)
      New derivations of origin-independent expressions for the electric permittivity are presented, starting either from the response function of the current density that defines the absorption coefficient, or from the off-resonance single-photon scattering amplitude that leads to the Kramers–Heisenberg dispersion formula. The resulting expression for the permittivity is compared with earlier work ...
    • Open-ended formulation of self-consistent field response theory with the polarizable continuum model for solvation 

      Di Remigio, Roberto; Beerepoot, Maarten; Cornaton, Yann; Ringholm, Magnus; Steindal, Arnfinn Hykkerud; Ruud, Kenneth; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-15)
      The study of high-order absorption properties of molecules is a field of growing importance. Quantumchemical studies can help design chromophores with desirable characteristics. Given that most experiments are performed in solution, it is important to devise a cost-effective strategy to include solvation effects in quantum-chemical studies of these properties. We here present an open-ended ...
    • Visible-light photocatalytic double C–H Functionalization of indoles: a synergistic experimental and computational study 

      Erdenebileg, Uranbaatar; Demissie, Taye Beyene; Hansen, Jørn H (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-21)
      Herein is disclosed a novel visible-light photocatalytic double C–H functionalization of indoles. The reaction affords 2,3-difunctional- ized indoles in up to 84% yield, but the reaction rate depends strongly on electronic substituent effects. Mechanistic DFT studies and control experiments suggest that the secondary functionalization occurs through an independent photocatalytic oxidation ...
    • Isolation and complete genome sequence of the thermophilic Geobacillus sp. 12AMOR1 from an Arctic deep-sea hydrothermal vent site 

      Wissuwa, Juliane; Stokke, Runar; Fedøy, Anita-Elin; Lian, Kjersti; Smalås, Arne O.; Steen, Ida Helene (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-24)
      Members of the genus Geobacillus have been isolated from a wide variety of habitats worldwide and are the subject for targeted enzyme utilization in various industrial applications. Here we report the isolation and complete genome sequence of the thermophilic starch-degrading Geobacillus sp. 12AMOR1. The strain 12AMOR1 was isolated from deep-sea hot sediment at the Jan Mayen hydrothermal Vent ...
    • Characterization of a cold-active and salt tolerant esterase identified by functional screening of Arctic metagenomic libraries 

      De Santi, Concetta; Altermark, Bjørn; Pierechod, Marcin Miroslaw; Ambrosino, Luca; de Pascale, Donatella; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-19)
      Background: The use of metagenomics in enzyme discovery constitutes a powerful approach to access to genomes of unculturable community of microorganisms and isolate novel valuable biocatalysts for use in a wide range of biotechnological and pharmaceutical fields. Results: Here we present a novel esterase gene (lip3) identified by functional screening of three fosmid metagenomic libraries, ...
    • The structure of the metallo-β-lactamase VIM-2 in complex with a triazolylthioacetamide inhibitor 

      Christopeit, Tony; Yang, Ke-Wu; Yang, Shao-Kang; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11)
      The increasing number of pathogens expressing metallo-β-lactamases (MBLs), and in this way achieving resistance to β-lactam antibiotics, is a significant threat to global public health. A promising strategy to treat such resistant pathogens is the co-administration of MBL inhibitors together with β-lactam antibiotics. However, an MBL inhibitor suitable for clinical use has not yet been identified. ...
    • Demetalation of copper undecaarylcorroles: Molecular structures of a free-base undecaarylisocorrole and a gold undecaarylcorrole 

      Capar, Jan; Zonneveld, Job; Berg, Steffen; Isaksson, Johan; Gagnon, Kevin J.; Kolle, Ekaney Thomas; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-27)
      Copper undecaarylcorroles were found to undergo acid-induced demetalation with unusual ease under both reductive and nonreductive conditions. The resulting free-base undecaarylcorroles were found to be rather reactive, readily photooxygenating to yield 5/10-hydroxyisocorroles and open-chain tetrapyrroles. The use of nonreductive conditions led to 50-75% yields of undecaarylisocorroles, a new class ...
    • Four-component relativistic density functional theory with the polarisable continuum model: application to EPR parameters and paramagnetic NMR shifts 

      Di Remigio, Roberto; Repisky, Michal; Komorovsky, Stanislav; Hrobárik, Peter; Frediani, Luca; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-01)
      The description of chemical phenomena in solution is as challenging as it is im- portant for the accurate calculation of molecular properties. Here, we present the implementation of the polarizable continuum model (PCM) in the four-component Dirac–Kohn–Sham density functional theory framework, o ↵ ering a cost-e ↵ ective way to concurrently model solvent and relativistic e ↵ ects. The ...
    • Indirect NMR spin-spin coupling constants in diatomic alkali halides 

      Jaszuński, Michał; Antušek, Andrej; Demissie, Taye Beyene; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-28)
      We report the Nuclear Magnetic Resonance (NMR) spin–spin coupling constants for diatomic alkali halides MX, where M = Li, Na, K, Rb, or Cs and X = F, Cl, Br, or I. The coupling constants are determined by supplementing the non-relativistic coupled-cluster singles-and-doubles (CCSD) values with relativistic corrections evaluated at the four-component density-functional theory (DFT) level. These ...
    • Biochemical characterization of a family 15 carbohydrate esterase from a bacterial marine Arctic metagenome 

      De Santi, Concetta; Willassen, Nils Peder; Williamson, Adele Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Background The glucuronoyl esterase enzymes of wood-degrading fungi (Carbohydrate Esterase family 15; CE15) form part of the hemicellulolytic and cellulolytic enzyme systems that break down plant biomass, and have possible applications in biotechnology. Homologous enzymes are predicted in the genomes of several bacteria, however these have been much less studied than their fungal counterparts. ...
    • Interpreting the paramagnetic NMR spectra of potential Ru(III) metallodrugs: synergy between experiment and relativistic DFT calculations 

      Novotný, Jan; Sojka, Martin; Komorovsky, Stanislav; Nečas, Marek; Marek, Radek (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-16)
      Ruthenium-based compounds are potential candidates for use as anticancer metallodrugs. The central ruthenium atom can be in the oxidation state +2 (e.g., RAPTA, RAED) or +3 (e.g., NAMI, KP). In this study we focus on paramagnetic NAMI analogs of a general structure [4-R-pyH]+ <i>trans</i>-[Ru<sup>III</sup>Cl<sub>4</sub>(DMSO)(4-R-py)]<sup>−</sup>, where 4-R-py stands for a 4-substituted pyridine. ...
    • Electronic structure of small surfactants: a continuum solvation study 

      Mozgawa, Krzysztof; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-07-18)
      The e ect of surfaces and interfaces on the structure and properties of molecules is of a great interest in a number of biological and technological applications. Nevertheless, such an investigation is extremely challenging from an experimental point of view, due to the bidimensionality of the environment. In recent years, we have developed a framework to study molecules at surfaces ...
    • A Decade of Biochemical and Structural Studies of the DNA Repair Machinery of Deinococcus radiodurans: Major Findings, Functional and Mechanistic Insight and Challenges 

      Timmins, Joanna; Moe, Elin (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-27)
      The Deinococcus radiodurans bacterium is extremely resistant to ionising radiation and desiccation and can withstand a 200-fold higher radiation dose than most other bacteria with no loss of viability. The mechanisms behind this extreme resistance are not fully understood, but it is clear that several factors contribute to this phenotype. Efficient scavenging of reactive oxygen species and repair ...
    • Magnetic properties with multiwavelets and DFT: The complete basis set limit achieved 

      Jensen, Stig Rune; Flå, Tor; Jonsson, Dan Johan; Monstad, Rune Sørland; Ruud, Kenneth; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-11)
      Multiwavelets are emerging as an attractive alternative to traditional basis sets such as Gaussian-type orbitals and plane waves. One of their distinctive properties is the ability to reach the basis set limit (often a chimera for traditional approaches) reliably and consistently by fixing the desired precision ε. We present our multiwavelet implementation of the linear response formalism, applied ...