Now showing items 81-100 of 581

    • 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 ...
    • Phenol- and resorcinol-appended metallocorroles and their derivatization with fluorous tags 

      Alemayehu, Abraham; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-10)
      Boron tribromide-mediated demethylation of rhenium-oxo and gold meso-tris(4-methoxyphenyl)corrole and meso-tris(3,5-dimethoxyphenylcorrole), M[TpOMePC] and M[T(3,5-OMe)PC] (M = ReO, Au), have yielded the corresponding phenol- and resorcinol-appended metallocorroles, M[TpOHPC] and M[T(3,5-OH)PC], in good yields. The latter compounds proved insoluble in dichloromethane and chloroform but soluble in ...
    • Spin-vibronic interaction induced reverse intersystem crossing: A case study with TXO-TPA and TXO-PhCz molecules 

      Karak, Pijush; Ruud, Kenneth; Chakrabarti, Swapan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-01)
      We highlight the important roles the direct spin–orbit (DSO) coupling, the spin-vibronic (SV) coupling, and the dielectric constant of the medium play on the reverse intersystem crossing (RISC) mechanism of TXO-TPA and TXO-PhCz molecules. To understand this complex phenomenon, we have calculated the RISC rate constant, kRISC, using a time-dependent correlation function-based method within the framework ...
    • Porphyryne 

      Ghosh, Abhik; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-25)
      Density functional theory calculations with the B3LYP*-D3 method with large STO-QZ4P basis sets unambiguously predict a singlet ground state for Zn-porphyryne. However, the calculations also predict a low singlet–triplet gap of about 0.4 eV and a high adiabatic electron affinity of 2.4 eV. Accordingly, the reactivity of porphyryne species may be dominated by electron transfer, hydrogen abstraction, ...
    • DFT studies of the redox behavior of oligo(aza)pyridines and experimental CVs of 4′-substituted terpyridines 

      Mateyise, Nandisiwe Ghandi Sibongile; Conradie, Marrigje M.; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-17)
      The cyclic voltammograms of a series of substituted terpyridine ligands are presented, showing that reduction occur generally below −2 V versus the redox potential of ferrocene. Density functional theory (DFT) calculated energies and the theoretically calculated reduction potentials of a large series of substituted oligo(aza)pyridine ligands (terpyridine, bipyridine and phenanthroline) are determined ...
    • A unique class I polyhydroxyalkanoate synthase (PhaC) from Brevundimonas sp. KH11J01 exists as a functional trimer: A comparative study with PhaC from Cupriavidus necator H16 

      Assefa, Netsanet Gizaw; Hansen, Hilde; Altermark, Bjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-06)
      Polyhydroxyalkanoates (PHAs) are natural biodegradable polyesters that are produced by numerous prokaryotic microorganisms primarily as a carbon- and energy reserve. The PhaC enzyme catalyzes the last step in the PHA biosynthesis pathway and synthesizes PHA polymers from hydroxyalkanoic acids. A type I PhaC from a PHAproducing marine bacterium Brevundimonas sp. KH11J01 (BrPhaC) was identified, ...
    • 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 ...
    • Vibrational Corrections to NMR Spin-Spin Coupling Constants from Relativistic Four-Component DFT Calculations 

      Jakubowska, Katarzyna; Pecul, Magdalena; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-22)
      Zero-point vibrational (ZPV) corrections to the nuclear spin–spin coupling constants have been calculated using four-component Dirac–Kohn–Sham DFT for H<sub>2</sub>X (where X = O, S, Se, Te, Po), XH<sub>3</sub> (where X = N, P, As, Sb, Bi), and XH<sub>4</sub> (where X = C, Si, Ge, Sn, and Pb) molecules and for HC≡CPbH<sub>3</sub>. The main goal was to study the influence of relativistic effects on ...
    • Structural Organization of S516 Group I Introns in Myxomycetes 

      Furulund, Betty Martine Normann; Karlsen, Bård Ove; Babiak, Igor; Haugen, Peik; Johansen, Steinar Daae (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-25)
      Group I introns are mobile genetic elements encoding self-splicing ribozymes. Group I introns in nuclear genes are restricted to ribosomal DNA of eukaryotic microorganisms. For example, the myxomycetes, which represent a distinct protist phylum with a unique life strategy, are rich in nucleolar group I introns. We analyzed and compared 75 group I introns at position 516 in the small subunit ...
    • Iridium(VII)-Corrole Terminal Carbides Should Exist as Stable Compounds 

      Alemayehu, Abraham; Conradie, Jeanet; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-14)
      Scalar-relativistic DFT calculations with multiple exchangecorrelation functionals and large basis sets foreshadow the existence of stable iridium(VII)−corrole terminal carbide derivatives. For the parent compound Ir[Cor](C), OLYP/STO-TZ2P calculations predict a short Ir− C bond distance of 1.69 Å, a moderately domed macrocycle with no indications of ligand noninnocence, a surprisingly low ...
    • Effektive læringsstrategier: Innsikter, implementering og tverrfaglig erfaringsutveksling 

      Beerepoot, Maarten (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-18)
      Forskning på læring viser tydelig at noen læringsstrategier er mer effektive enn andre. To spesielt effektive læringsstrategier er å hente fram fra hukommelsen gjennom for eksempel testing (retrieval practice) og fordeling av læringen over en lengre periode med jevne mellomrom (distributed practice). Forskning viser imidlertid også at studenter i liten grad er bevisste på hva som er mest effektiv ...
    • QTAIM analysis dataset for non-covalent interactions in curan clusters 

      Malloum, Alhadji; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-21)
      Furan clusters are very important to understand the dynam- ics and properties of the furan solvent. They can be used combined with quantum cluster equilibrium theory to theo- retically determine the thermodynamics properties of the fu- ran solvent. To understand the structures of the furan clus- ters, one needs to understand the non-covalent interactions that hold the furan molecules together. ...
    • Twist-Bent Bonds Revisited: Adiabatic Ionization Potentials Demystify Enhanced Reactivity 

      Ghosh, Abhik; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-11)
      Explicit calculations of vertical and adiabatic ionization potentials of cyclopropane derivatives with modern DFT methods have underscored the possibility of unusually large reorganization energies (defined as the difference between vertical and adiabatic ionization potentials) of 0.5–1.0 eV for several compounds. Such is the case for ionization of the twist-bent σ-bond of trans-bicyclo[4.1.0]hept-3-ene ...
    • Review of DFT-simulated and experimental electrochemistry properties of the polypyridyl Row-1 Mn, Fe & Co, and Group-8 Fe, Ru and Os MLCT complexes 

      Von Eschwege, Karel G.; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-30)
      Ruthenium had up to date been pivotal in electro- and photocatalytic applications involving reduction of CO<sub>2</sub> and H<sub>2</sub>O, and dye-sensitized solar cells. Commercial applications would seek use of earth-abundant metals instead. Towards this goal, it is key to review the synthesis, electrochemical and spectroscopical properties of associated metal-to-ligand charge transfer complexes ...
    • Exact two-component Hamiltonians for relativistic quantum chemistry: Two-electron picture-change corrections made simple 

      Knecht, Stefan; Repisky, Michal; Jensen, Hans Jørgen Aagaard; Saue, Trond (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-19)
      Based on self-consistent field (SCF) atomic mean-field (amf) quantities, we present two simple yet computationally efficient and numerically accurate matrix-algebraic approaches to correct both scalar-relativistic and spin–orbit two-electron picture-change effects (PCEs) arising within an exact two-component (X2C) Hamiltonian framework. Both approaches, dubbed amfX2C and e(xtended)amfX2C, allow us ...
    • The four-component DFT method for the calculation of the EPR g-tensor using a restricted magnetically balanced basis and London atomic orbitals 

      Misenkova, Debora; Lemken, Florian; Repisky, Michal; Noga, Jozef; Malkina, Olga L.; Komorovsky, Stanislav (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-28)
      ABSTRACT Four-component relativistic treatments of the electron paramagnetic resonance g-tensor have so far been based on a common gauge origin and a restricted kinetically balanced basis. The results of such calculations are prone to exhibit a dependence on the choice of the gauge origin for the vector potential associated with uniform magnetic field and a related dependence on the basis set ...
    • Data to Understand the Nature of Non-Covalent Interactions in the Thiophene Clusters 

      Malloum, Alhadji; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-10)
      We have reported herein the data to understand the nature and number of non-covalent interactions that stabilize the structures of the thiophene clusters. In addition, we have also provided the optimized Cartesian coordinates of all the structures of the investigated thiophene clusters. Initially, the geometries have been generated using the ABCluster code which performs a global optimization to ...
    • Comparing Isoelectronic, Quadruple-Bonded Metalloporphyrin and Metallocorrole Dimers: Scalar-Relativistic DFT Calculations Predict a > 1-eV Range for Ionization Potential and Electron Affinity 

      Conradie, Jeanet; Vazquez-Lima, Hugo; Alemayehu, Abraham; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-21)
      A scalar-relativistic DFT study of isoelectronic, quadruple-bonded Group 6 metalloporphyrins (M = Mo, W) and Group 7 metallocorroles (M = Tc, Re) has uncovered dramatic differences in ionization potential (IP) and electron affinity (EA) among the compounds. Thus, both the IPs and EAs of the corrole derivatives are 1 eV or more higher than those of the porphyrin derivatives. These differences ...
    • Dimethylsulfoxide (DMSO) Clusters Dataset: DFT Relative Energies, Non-Covalent Interactions, and Cartesian Coordinates 

      Malloum, Alhadji; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-07)
      Theoretical understanding of dimethylsulfoxide (DMSO) liquid depends on the understanding of the DMSO clusters. In this work, we provide the structures and the energetics of the DMSO clusters. The structures have been generated using ABCluster and further optimized at the MP2/aug-ccpVDZ level of theory. The final structures have been optimized at two different levels of theory: PW6B95D3/aug-ccpVDZ ...
    • Electronic and structural data of 4’-substituted bis(2,2’;6’2’’-terpyridine)manganese in mono-, bis-, tris- and tetra-cationic states from DFT calculations 

      Conradie, Jeanet (Journal article; Tidsskriftartikkel, 2022-04-30)
      This data article provides density functional theory calculated structural (bond lengths and angles, coordinates of optimized geometries) and electronic (Mulliken spin population and character of frontier molecular orbitals) data of a series of 4’-substituted bis(2,2’;6’2’’-terpyridine)manganese complexes in four different oxidation states. The bis-cationic (n = 2) [Mn(tpy)<sub>2</sub>]<sup>2+</sup> ...