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norskInstitutt for kjemi
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Automatisk rettet eksamen i generell kjemi
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-29)En god avsluttende eksamen vurderer i hvilken grad intendert læringsutbytte har blitt oppnådd på en objektiv, reproduserbar og helst autentisk måte. Det er imidlertid lite tilfredsstillende hvis en faglærer bruker mye tid på vurdering av læring framfor vurdering for læring underveis i semesteret. Derfor kan det være attraktivt å utforske muligheter med en digital automatisk rettet eksamen, spesielt ... -
Hyperspectral imaging and deep learning for parasite detection in white fish under industrial conditions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-11-09)Parasites in fish muscle present a significant problem for the seafood industry in terms of both quality and health and safety, but the low contrast between parasites and fish tissue makes them exceedingly difficult to detect. The traditional method to identify nematodes requires removing fillets from the production line for manual inspection on candling tables. This technique is slow, labor intensive ... -
Removal of per- and polyfluoroalkyl substances (PFAS) from water using magnetic cetyltrimethylammonium bromide (CTAB)-modified pine bark
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-09-02)Per- and polyfluoroalkyl substances (PFAS) have gained global attention in recent years due to their adverse effect on environment and human health. In this study, a novel and cost-effective sorbent was developed utilizing forestry by-product pine bark and tested for the removal of PFAS compounds from both synthetic solutions and contaminated groundwater. The synthesis of the adsorbent included two ... -
A conservative stochastic Dirac-Klein-Gordon system
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-04)Considered herein is a particular nonlinear dispersive stochastic system consisting of Dirac and Klein-Gordon equations. They are coupled by nonlinear terms due to the Yukawa interaction. We consider a case of homogeneous multiplicative noise that seems to be very natural from the perspective of the least action formalism. We are able to show existence and uniqueness of a corresponding Cauchy problem ... -
Fitting to magnetic forces improves the reliability of magnetic Moment Tensor Potentials
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-29)We developed a method for fitting machine-learning interatomic potentials with magnetic degrees of freedom, namely, magnetic Moment Tensor Potentials (mMTP). The main feature of our method consists in fitting mMTP to magnetic forces (negative derivatives of energies with respect to magnetic moments) as obtained spin-polarized density functional theory calculations. We test our method on the bcc Fe–Al ... -
Nickel Catalyzed Carbonylative Cross Coupling for Direct Access to Isotopically Labeled Alkyl Aryl Ketones
(Journal article; Tidsskriftartikkel, 2024-08-15)Here we present an effective nickel-catalyzed carbonylative cross-coupling for direct access to alkyl aryl ketones from readily accessible redox-activated tetrachlorophthalimide esters and aryl boronic acids. The methodology, which is run employing only 2.5 equivalents of CO and simple Ni(II) salts as the metal source, exhibits a broad substrate scope under mild conditions. Furthermore, this ... -
Computational Study of the Ir-Catalyzed Formation of Allyl Carbamates from CO2
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-05)We have employed computational methods to investigate the iridium-catalyzed allylic substitution leading to the formation of enantioenriched allyl carbamates from carbon dioxide (CO<sub>2</sub>). The reaction occurs in several steps, with initial formation of an iridium-allyl, followed by nucleophilic attack by the carbamate formed in situ from CO<sub>2</sub> and an amine. A detailed isomeric analysis ... -
Revisiting the mechanism of asymmetric Ni-catalyzed reductive carbo-carboxylation with CO2: The additives affect the product selectivity
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-25)The mechanistic details of the asymmetric Ni-catalyzed reductive cyclization/carboxylation of alkenes with CO2 have been revisited using DFT methods. Emphasis was put on the enantioselectivity and the mechanistic role of Lewis acid additives and in situ formed salts. Our results show that oxidative addition of the substrate is rate-limiting, with the formed Ni(II)-aryl intermediate preferring a ... -
Preparation of a high-coordinated-silicon-centered spiro-cyclic compound
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-10)Silicon compounds containing silicon–silicon bond with a variety of unusual oxidation states are quite important, because their high reactivity leads to the formation of a variety of silicon compounds. The isolation of such compounds with unusual oxidation states requires a resilient synthetic strategy. Herein, we report the synthesis of a silicon based spirocyclic compound containing a hyper-valent ... -
SARS-CoV2 Nsp1 is a metal-dependent DNA and RNA endonuclease
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-28)Over recent years, we have been living under a pandemic, caused by the rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). One of the major virulence factors of Coronaviruses is the Non-structural protein 1 (Nsp1), known to suppress the host cells protein translation machinery, allowing the virus to produce its own proteins, propagate and invade new cells. To ... -
Generating and grading 34 optimised norm-conserving Vanderbilt pseudopotentials for actinides and super-heavy elements in the PseudoDojo
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-07)In the last decades, material discovery has been a very active research field driven by the need to find new materials for many different applications. This has also included materials with heavy elements, beyond the stable isotopes of lead, as most actinides exhibit unique properties that make them useful in various applications. Furthermore, new heavy elements beyond actinides, collectively referred ... -
Tinned: A symbolic library for response theory and high-order derivatives
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-23)A symbolic C++ library—Tinned—has been developed for symbolic differentiation and manipulation in response theory. By recognizing different key building blocks in the density matrix-based (Thorvaldsen et al., J. Chem. Phys. 2008, 129, 214108) and coupled-cluster response theories, we have implemented their corresponding C++ symbolic classes, including but not limited to one- and two-electron ... -
Combination of separation and degradation methods after PFAS soil washing
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-26)The current study evaluated a three-stage treatment to remediate PFAS-contaminated soil. The treatment consisted of soil washing, foam fractionation (FF), and electrochemical oxidation (EO). The possibility of replacing the third stage, i.e., EO, with an adsorption process was also assessed. The contamination in the studied soils was dominated by perfluorooctane sulfonate (PFOS), with a concentration ... -
Inverse Hypercorroles
(Journal article; Tidsskriftartikkel, 2024-05-02)Ground-state and time-dependent density functional theory (TDDFT) calculations with the long-range-corrected, Coulomb-attenuating CAMY-B3LYP exchange-correlation functional and large, all-electron STO-TZ2P basis sets have been used to examine the potential “inverse hypercorrole” character of meso-p-nitrophenyl-appended dicyanidocobalt(III) corrole dianions. The effect is most dramatic for ... -
Electronic Structure of Metallophlorins: Lessons from Iridium and Gold Phlorin Derivatives
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-14)Phlorins have long remained underexplored relative to their fully conjugated counterparts, such as porphyrins, hydroporphyrins, and corroles. Herein, we have attempted to bridge that knowledge gap with a scalar-relativistic density functional theory (DFT) study of unsubstituted iridium and gold phlorin derivatives and a multitechnique experimental study of iridium-bispyridine and gold complexes of ... -
Kinetically-Controlled Ni-Catalyzed Direct Carboxylation of Unactivated Secondary Alkyl Bromides without Chain Walking
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-09)Herein, we report the direct carboxylation of unactivated secondary alkyl bromides enabled by the merger of photoredox and nickel catalysis, a previously inaccessible endeavor in the carboxylation arena. Site-selectivity is dictated by a kinetically controlled insertion of CO<sub>2</sub> at the initial C(sp<sup>3</sup> )−Br site by the rapid formation of Ni(I)−alkyl species, thus avoiding undesired ... -
Synthesis of Cryptophanes: Recent Advances
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-28)This review covers the latest developments in the synthesis of cryptophane host molecules since the publication of the last extensive review by Brotin and Dutasta in 2009. The literature has been categorized according to the synthetic method for generating the cryptophane core and we also emphasize emerging late-stage functionalization approaches. The synthetic strategies towards cryptophanes ... -
VAMPyR—A high-level Python library for mathematical operations in a multiwavelet representation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-26)Wavelets and multiwavelets have lately been adopted in quantum chemistry to overcome challenges presented by the two main families of basis sets: Gaussian atomic orbitals and plane waves. In addition to their numerical advantages (high precision, locality, fast algorithms for operator application, linear scaling with respect to system size, to mention a few), they provide a framework that narrows ... -
Asymmetric Boracarboxylation of Styrenes Using Carbon Dioxide
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-22)The boracarboxylation reaction has potential for the production of natural products and drug candidates, but the development of an asymmetric version of this transformation is challenging. We report an enantioselective boracarboxylation of styrenes, enabled by a copper catalyst containing chiral phosphines. Our experimental conditions provide yields between 31–76% and enantiomeric ratios from ... -
Hypsochlorins
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-19)Both the Soret and Q bands of chlorin e6 complexes blueshift on going from Zn to Pd to Pt as the coordinated metal, establishing the latter two complexes as hypsochlorins. DFT/TDDFT calculations indicate that the blueshifts appear to be related to the presence of the electronegative metal ion, which lowers the orbital energies of the HOMO and HOMO-1, while leaving the LUMOs relatively unaffected.
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