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norskInstitutt for kjemi: Recent submissions
Now showing items 421-440 of 581
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Analytic calculations of anharmonic infrared and Raman vibrational spectra
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-07)Using a recently developed recursive scheme for the calculation of high-order geometric derivatives of frequency-dependent molecular properties [Ringholm et al., J. Comp. Chem., 2014, 35, 622], we present the first analytic calculations of anharmonic infrared (IR) and Raman spectra including anharmonicity both in the vibrational frequencies and in the IR and Raman intensities. In the case of anharmonic ... -
How accurate is DFT for iridium-mediated chemistry?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-27)Iridium chemistry is versatile and widespread, with superior performance for reaction types such as enantioselective hydrogenation and C−H activation. In order to gain insight into the mechanistic details of such systems, density functional theory (DFT) studies are often employed. But how accurate is DFT for modeling iridium-mediated transformations in solution? We have evaluated how well DFT ... -
Non-nearest neighbour ICD in clusters
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-19)Interatomic Coulombic decay (ICD) is an electronic decay process of excited, ionized systems. It has been shown to occur in a multitude of small and large systems. The effects of more than one possible decay partner are discussed in detail illustrated by simulated ICD electron spectra of NeAr clusters and pure Ne clusters. Hereby, the mostly underestimated contribution of decay with non-nearest ... -
Studies Towards the Synthesis of DKP Analogues. Investigations of Bis-lactim Ether Reactivity with Aldehydes and Ketones
(Master thesis; Mastergradsoppgave, 2016-05-19)A group of molecules with the name diketopiperazines (DKP) are called so, because of their diketopiperazine ring as the core structural unit. Mainly there are 3 types of diketopiperazies which only differ in in the position of the keto group, one type has the keto groups in 2,3- position; another in 2,5-; and the third in 2,6- position. The 2,5- isomer has attracted great interest, because of compounds ... -
Characterization and structural analysis of class D β-lactamases: variants and mutants of OXA-type carbapenemases
(Master thesis; Mastergradsoppgave, 2016-05-18)The rise and spread of antibiotic resistant bacteria is posing a serious threat to the global health; antibiotic drugs are rendered ineffective and common infectious diseases become harder or impossible to treat. The beta-lactamase enzymes, with their ability to hydrolyze the beta-lactam antibiotics, are a major cause of resistant bacteria. The OXA-beta-lactamase enzymes are one of the most alarming ... -
An Insight into the Aliivibrio genus. A comparative study on relationships and traits of species within the genus Aliivibrio
(Master thesis; Mastergradsoppgave, 2016-05-18)Few studies have emphasized on the genus Aliivibrio as a whole and lags behind the better known Vibrio. Nevertheless, the Aliivibrio has for several decades been associated with species expressing bioluminescence like the Aliivibrio fischeri, but has also been linked to costly diseases in the fish farming industry such as Aliivibrio salmonicida. In an attempt to gain insight in the genus on a ... -
Novel antimicrobial peptides EeCentrocins 1, 2 and EeStrongylocin 2 from the Edible sea urchin Echinus esculentus have 6-br-trp post-translational modifications
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-23)The global problem of microbial resistance to antibiotics has resulted in an urgent need to develop new antimicrobial agents. Natural antimicrobial peptides are considered promising candidates for drug development. Echinoderms, which rely on innate immunity factors in the defence against harmful microorganisms, are sources of novel antimicrobial peptides. This study aimed to isolate and characterise ... -
Open-ended response theory with polarizable embedding: multiphoton absorption in biomolecular systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-19)We present the theory and implementation of an open-ended framework for electric response properties at the level of Hartree–Fock and Kohn–Sham density functional theory that includes effects from the molecular environment modeled by the polarizable embedding (PE) model. With this new state-of-the-art multiscale functionality, electric response properties to any order can be calculated for molecules ... -
Complete genome sequence of Halomonas sp. R5-57
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)The marine Arctic isolate Halomonas sp. R5-57 was sequenced as part of a bioprospecting project which aims to discover novel enzymes and organisms from low-temperature environments, with potential uses in biotechnological applications. Phenotypically, Halomonas sp. R5-57 exhibits high salt tolerance over a wide range of temperatures and has extra-cellular hydrolytic activities with several ... -
A polarizable continuum model for molecules at spherical diffuse interfaces
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-22)We present an extension of the Polarizable Continuum Model (PCM) to simulate solvent effects at diffuse interfaces with spherical symmetry, such as nanodroplets and micelles. We derive the form of the Green’s function for a spatially varying dielectric permittivity with spherical symmetry and exploit the integral equation formalism of the PCM for general dielectric environments to recast the solvation ... -
Fragment-Based Drug Discovery
(Journal article; Tidsskriftartikkel, 2015-06-13) -
Iron/Brønsted Acid Catalyzed Asymmetric Hydrogenation: Mechanism and Selectivity-Determining Interactions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-03)Hydrogenation catalysts involving abundant base metals such as cobalt or iron are promising alternatives to precious metal systems. Despite rapid progress in this field, base metal catalysts do not yet achieve the activity and selectivity levels of their precious metal counterparts. Rational improvement of base metal complexes is facilitated by detailed knowledge about their mechanisms and ... -
ASM Microbe 2016
(Journal article; Tidsskriftartikkel, 2016-09-12) -
Total synthesis of tubastrine and 3-dehydroxy tubastrine by microwave-assisted cross-coupling reactions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-03)The first syntheses of tubastrine and 3-dehydroxy tubastrine are described. The target compounds were prepared in four consecutive steps from commercially available starting materials. The central scaffold was formed by a microwave-assisted C–N cross-coupling reaction between 1,3-bis(<i>tert</i>-butoxycarbonyl)-guanidine and (<i>E</i>)-((4-(2-iodovinyl)-1,2-phenylene)bis(oxy))bis(<i>tert</i>-butyl ... -
Palladium(0)-Catalyzed Cross-Couplings of 2-Bromophosphinine
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013-05-21)A new Negishi-type cross-coupling of 2-bromophosphinine has been developed. The new method expands the scope of palladium-catalyzed couplings to monobromophosphinines, which have been considered as poor substrates so far. Moreover, aryl-, alkenyl-, and alkynylzinc bromides were found to be effective coupling partners. -
Experimental and four-component relativistic DFT studies of tungsten carbonyl complexes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-24)We present a theoretical and experimental study of the structure and nuclear magnetic resonance (NMR) parameters of the pentacarbonyltungsten complexes of η<sup>1</sup>-2-(trimethylstannyl)-4,5-dimethylphosphinine, η<sup>2</sup>-norbornene, and imidazolidine-2-thione. The three complexes have a pseudo-octahedral molecular structure with the six ligands bonded to the tungsten atom. The η<sup>1</sup ... -
Iridium-PHOX-mediated alkene hydrogenation: Isomerisation influences the stereochemical outcome
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-05-27)Recent experimental studies of iridium-phosphinooxazoline-mediated alkene hydrogenation indicated two dihydride species as resting states, with the minor isomer assumed to give rise to the major product enantiomer [Gruber and Pfaltz, Angew. Chem. Int. Ed. 2014, 53, 1896]. B3LYP-D2 calculations confirm the two dihydride intermediates as resting states but show that these species do not give rise to ... -
A combined quantum mechanics/molecular mechanics study of the one- and two-photon absorption in the green fluorescent protein
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012-02-01)We present for the first time a QM/MM study of the one- and two-photon absorption spectra of the GFP chromophore embedded in the full protein environment described by an advanced quantum mechanically derived polarizable force field. The calculations are performed on a crystal structure of the green fluorescent protein (GFP) using the polarizable embedding density functional theory (PE-DFT) scheme. ... -
Properties and distribution of a metallo-β-lactamase (ALI-1) from the fish pathogen Aliivibrio salmonicida LFI1238
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015)Objectives. To characterize the chromosome-encoded metallo-β-lactamase (MBL) from the psychrophilic, marine fish-pathogenic bacterium Aliivibrio salmonicida LFI1238 and check for the presence of the gene in other Aliivibrio isolates both connected to the fish-farming industry and from the environment. Methods. The MBL gene was cloned and intracellularly expressed in Escherichia coli. Kinetic ... -
Ligand noninnocence in FeNO corroles: insights from β-octabromocorrole complexes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-30)The first FeNO octabromocorroles have been synthesized including four β-octabromo-meso-tris(p-X-phenyl)corrole derivatives Fe[Br8TpXPC](NO) (X = CF3, H, CH3, OCH3) and the β-octabromo-meso-tris(pentafluorophenyl)corrole complex, Fe[Br8TPFPC](NO). The last complex, which proved amenable to single-crystal X-ray structure determination, exhibits the geometry parameters: Fe–N(O) 1.643(8) Å, N–O 1.158(9) ...
