Institutt for kjemi: Recent submissions
Now showing items 201-220 of 623
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Generalization of Intrinsic Orbitals to Kramers-Paired Quaternion Spinors, Molecular Fragments, and Valence Virtual Spinors
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-08)Localization of molecular orbitals finds its importance in the representation of chemical bonding (and antibonding) and in the local correlation treatments beyond mean-field approximation. In this paper, we generalize the intrinsic atomic and bonding orbitals [G. Knizia, J. Chem. Theory Comput. 2013, 9, 11, 4834–4843] to relativistic applications using complex and quaternion spinors, as well as to ... -
Implementation of Relativistic Coupled Cluster Theory for Massively Parallel GPU-Accelerated Computing Architectures
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-09)In this paper, we report reimplementation of the core algorithms of relativistic coupled cluster theory aimed at modern heterogeneous high-performance computational infrastructures. The code is designed for parallel execution on many compute nodes with optional GPU coprocessing, accomplished via the new ExaTENSOR back end. The resulting ExaCorr module is primarily intended for calculations of molecules ... -
Understanding Hyperporphyrin Spectra: TDDFT Calculations on Diprotonated Tetrakis(p-aminophenyl)porphyrin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-29)A detailed TDDFT study (with all-electron STO-TZ2P basis sets and the COSMO solvation model) has been carried out on the effect of diprotonation on the UV−vis−NIR spectra of free-base tetraphenylporphyrin and tetrakis(p-aminophenyl)porphyrin. The diprotonated forms have been modeled as their bis-formate complexes, i.e., as so-called porphyrin diacids. The dramatic redshift of the Q-band of ... -
Phylogenetic Revision of the Genus Aliivibrio: Intra- and Inter-Species Variance Among Clusters Suggest a Wider Diversity of Species
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-18)Genus Aliivibrio is known to harbor species exhibiting bioluminescence as well as pathogenic behavior affecting the fish farming industry. Current phylogenetic understanding of Aliivibrio has largely remained dormant after reclassification disentangled it from the Vibrio genus in 2007. There is growing evidence of wider diversity, but until now the lack of genomes and selective use of type strains ... -
Regioselective formylation of rhenium-oxo and gold corroles: Substituent effects on optical spectra and redox potentials
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-28)Vilsmeier–Haack formylation of ReO and Au meso-triarylcorroles over 16–18 hours affords moderate to good yields (47–65%) of the ReO-3-formyl and Au-3,17-diformyl derivatives in a highly regioselective manner. Formylation was found to effect substantial upshifts for redox potentials (especially the reduction potentials) as well as significant to dramatic redshifts for both the Soret and Q bands. -
Mechanistic Insights into Copper-Catalyzed Carboxylations
(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 ... -
Phidianidine A and Synthetic Analogues as Naturally Inspired Marine Antifoulants
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-15)Stationary and slow-moving marine organisms regularly employ a natural product chemical defense to prevent being colonized by marine micro- and macroorganisms. While these natural antifoulants can be structurally diverse, they often display highly conserved chemistries and physicochemical properties, suggesting a natural marine antifouling pharmacophore. In our current report, we investigate the ... -
Anti-proliferative activity of a novel tricyclic triterpenoid acid from Commiphora africana resin against four human cancer cell lines
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-17)Myrrh, a resin derived from the damaged bark of Commiphora genus, has traditionally been used for treatment of various human diseases, such as amenorrhea, ache, tumors, fever, and stomach pains. In spite of this widespread use of the myrrh in Ethiopia, the pharmacological activity and chemical composition have not been studied in detail. A new tricyclic triterpene acid (3S,4S,14S,7E,17E,21Z)-3, ... -
Multiwavelets applied to metal–ligand interactions: Energies free from basis set errors
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-02)Transition metal-catalyzed reactions invariably include steps where ligands associate or dissociate. In order to obtain reliable energies for such reactions, sufficiently large basis sets need to be employed. In this paper, we have used high-precision multiwavelet calculations to compute the metal–ligand association energies for 27 transition metal complexes with common ligands, such as H2, CO, ... -
Simple, Axial Ligand-Mediated Route to Water-Soluble Iridium Corroles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-15)The synthesis and purification of water-soluble porphyrin-type compounds for photodynamic therapy and other medical applications is often a tedious exercise. Here, we have investigated the simple stratagem of adding a water-soluble axial ligand to the standard protocol for iridium insertion into simple meso-triarylcorroles. Early results showed that six-coordinate Ir[TpXPC](dna)2 derivatives, in ... -
Synthesis of Potential Metallo-β-Lactamase Inhibitors
(Master thesis; Mastergradsoppgave, 2012-06-04)Oppgaven omhandler syntesen av mulige metallo-beta-lactamaser inhibitorer. -
Novel DYRK1A Inhibitor Rescues Learning and Memory Deficits in a Mouse Model of Down Syndrome
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-17)Down syndrome (DS) is a complex genetic disorder associated with substantial physical, cognitive, and behavioral challenges. Due to better treatment options for the physical co-morbidities of DS, the life expectancy of individuals with DS is beginning to approach that of the general population. However, the cognitive deficits seen in individuals with DS still cannot be addressed pharmacologically. ... -
ThermoSlope: A Software for Determining Thermodynamic Parameters from Single Steady-State Experiments
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-26)The determination of the temperature dependence of enzyme catalysis has traditionally been a labourious undertaking. We have developed a new approach to the classical Arrhenius parameter estimation by fitting the change in velocity under a gradual change in temperature. The evaluation with a simulated dataset shows that the approach is valid. The approach is demonstrated as a useful tool by ... -
Anti-Colonization Effect of Au Surfaces with Self-Assembled Molecular Monolayers Functionalized with Antimicrobial Peptides on S. epidermidis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-10)Medical devices with an effective anti-colonization surface are important tools for combatting healthcare-associated infections. Here, we investigated the anti-colonization efficacy of antimicrobial peptides covalently attached to a gold model surface. The gold surface was modified by a self-assembled polyethylene glycol monolayer with an acetylene terminus. The peptides were covalently connected ... -
Synthesis of 5,7-diarylindoles via Suzuki-Miyaura coupling in water
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-16)The synthesis of novel 5,7-diaryl and diheteroaryl indoles has been explored via efficient double Suzuki–Miyaura coupling. The method notably employs a low catalyst loading of Pd(PPh<sub>3</sub>)<sub>4</sub> (1.5 mol%/coupling) and water as the reaction solvent to obtain 5,7-diarylated indoles without using N-protecting groups in up to 91% yield. The approach is also suitable for N-protected and ... -
Relativistic Four-Component DFT Calculations of Vibrational Frequencies
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-29)We investigate the effect of relativity on harmonic vibrational frequencies. Density functional theory (DFT) calculations using the four-component Dirac–Coulomb Hamiltonian have been performed for 15 hydrides (H<sub>2</sub>X, X = O, S, Se, Te, Po; XH<sub>3</sub>, X = N, P, As, Sb, Bi; and XH<sub>4</sub>, X = C, Si, Ge, Sn, Pb) as well as for HC≡CPbH<sub>3</sub>. The vibrational frequencies have been ... -
The Dog That Didn't Bark: A New Interpretation of Hypsoporphyrin Spectra and the Question of Hypsocorroles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-11)Nearly a half-century after Gouterman classified the UV–vis–NIR spectra of porphyrin derivatives as normal, hyper, or hypso, we propose a heretofore unsuspected “mechanism” underlying hypso spectra. Hypsoporphyrins, which exhibit blueshifted optical spectra relative to normal porphyrins (such as Zn porphyrins), typically involve dn transition metal ions, where n > 6. The spectral blueshifts have ... -
Synthesis, Spectroscopy, Electrochemistry and DFT of Electron-Rich Ferrocenylsubphthalocyanines
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-01)A series of novel ferrocenylsubphthalocyanine dyads Y-BSubPc(H)<sub>12</sub> with ferrocenylcarboxylic acids Y-H = (FcCH<sub>2</sub>CO<sub>2</sub>-H), (Fc(CH<sub>2</sub>)<sub>3</sub>CO<sub>2</sub>-H) or (FcCO(CH<sub>2</sub>)<sub>2</sub>CO<sub>2</sub>-H) in the axial position were synthesized from the parent Cl-BSubPc(H)<sub>12</sub> via an activated triflate-SubPc intermediate. UV/Vis data revealed ... -
X-ray absorption spectroscopy of exemplary platinum porphyrin and corrole derivatives: metal- versus ligand-centered oxidation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-30)A combination of Pt L<sub>3</sub>-edge X-ray absorption spectroscopy (EXAFS and XANES) and DFT (TPSS) calculations have been performed on powder samples of the archetypal platinum porphyrinoid complexes Pt<sup>II</sup>[TpCF<sub>3</sub>PP], Pt<sup>IV</sup>[TpCF<sub>3</sub>PP]Cl<sub>2</sub>, and Pt<sup>IV</sup>[TpCF<sub>3</sub>PC](Ar)(py), where TpCF<sub>3</sub>PP<sup>2-</sup> = meso-tetrakis(p-tr ... -
Ligand-Centered Triplet Diradical Supported by a Binuclear Palladium(II) Dipyrrindione
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-04)Oligopyrroles form a versatile class of redox-active ligands and electron reservoirs. Although the stabilization of radicals within oligopyrrolic π systems is more common for macrocyclic ligands, bidentate dipyrrindiones are emerging as compact platforms for one-electron redox chemistry in transition-metal complexes. We report the synthesis of a bis(aqua) palladium(II) dipyrrindione complex and its ...